SPX domain; We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organizms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 323 RIRLFIESPLPSDDEEGDEAANADSVSLSDDASSRKSIEKQIIE-------LPATPTRRFSTIPEDGPEG-------ETK 388
Cdd:pfam03105  31 KIQRELESTPPSSSPSSSDSGSAASPSDSTTSLPLRDPLSRSSSldrafggLVPSPPSSSSSSSSDSSSSsnsssssSSS 110

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 389 EQKVKRQSEIRRKRGTRSREIViPLTADTQFLDTLTHALQNLSNIQTHQHDNFMLETESLCSAVA-----RASSPYASKN 463
Cdd:pfam03105 111 SPSLLRRLPSESDDSSESYETT-PLDSEDEFFERLDSELNKVNKFYKEKEEEFLERLEALNKQLEalrdfRIKLIRESKS 189

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 464 DLYVWREIFGLW-VEMQVFESQREKDRGELSIDESEarlKRFALELAKRGWIHDPNAPTPSKKGK--LVKLKIGSGPSSQ 540
Cdd:pfam03105 190 DLYRWREPFGLYsSDSSVFFSTSELDSGNSSESSVD---DEVEEELERNGWISPIKSKDKKKRPSeaLDKVKTPDRTLKG 266

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1730128243 541 GLQ----------NQTSATAIED-----FLRLNFALLDVKKFQRVNVEAARKILKKHDKRTALTASNDLRTFM 598
Cdd:pfam03105 267 FLDasrrdylnriNKVNLRKAKKklkkaFIELYRGLELLKSYSELNRTAFRKILKKFDKVTSLNASKDYMKEV 339

transcriptional regulator ICP4; Provisional

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243   57 RPEDDPASSTASSPKDktRPLDSSVDDR----DSAIADESGNSSEQEEDSTGRPKKLTPAGKWISDFSVDMIRRASSPGD 132
Cdd:PHA03307   207 PRRSSPISASASSPAP--APGRSAADDAgassSDSSSSESSGCGWGPENECPLPRPAPITLPTRIWEASGWNGPSSRPGP 284

                           90       100       110       120       130       140       150       160
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243  133 RTTAENTPIANARSSTQHPGASQRSSSATHHLDVPSS-----SKQRRYSDGVQELSASLEDSHLEP--NARGRASFNVGS 205
Cdd:PHA03307   285 ASSSSSPRERSPSPSPSSPGSGPAPSSPRASSSSSSSresssSSTSSSSESSRGAAVSPGPSPSRSpsPSRPPPPADPSS 364

                          170       180       190       200       210       220       230       240
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243  206 VPDPERGASIGRKDLAAMRKNRRPSDIDAPDHSEPRSHEPSPGhhdwTASKwreeakldwdPSSISLKAGATKLSPPPRD 285
Cdd:PHA03307   365 PRKRPRPSRAPSSPAASAGRPTRRRARAAVAGRARRRDATGRF----PAGR----------PRPSPLDAGAASGAFYARY 430

                   .
gi 1730128243  286 R 286
Cdd:PHA03307   431 P 431

SPX domain; We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organizms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 323 RIRLFIESPLPSDDEEGDEAANADSVSLSDDASSRKSIEKQIIE-------LPATPTRRFSTIPEDGPEG-------ETK 388
Cdd:pfam03105  31 KIQRELESTPPSSSPSSSDSGSAASPSDSTTSLPLRDPLSRSSSldrafggLVPSPPSSSSSSSSDSSSSsnsssssSSS 110

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 389 EQKVKRQSEIRRKRGTRSREIViPLTADTQFLDTLTHALQNLSNIQTHQHDNFMLETESLCSAVA-----RASSPYASKN 463
Cdd:pfam03105 111 SPSLLRRLPSESDDSSESYETT-PLDSEDEFFERLDSELNKVNKFYKEKEEEFLERLEALNKQLEalrdfRIKLIRESKS 189

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 464 DLYVWREIFGLW-VEMQVFESQREKDRGELSIDESEarlKRFALELAKRGWIHDPNAPTPSKKGK--LVKLKIGSGPSSQ 540
Cdd:pfam03105 190 DLYRWREPFGLYsSDSSVFFSTSELDSGNSSESSVD---DEVEEELERNGWISPIKSKDKKKRPSeaLDKVKTPDRTLKG 266

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1730128243 541 GLQ----------NQTSATAIED-----FLRLNFALLDVKKFQRVNVEAARKILKKHDKRTALTASNDLRTFM 598
Cdd:pfam03105 267 FLDasrrdylnriNKVNLRKAKKklkkaFIELYRGLELLKSYSELNRTAFRKILKKFDKVTSLNASKDYMKEV 339

SPX domain; We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organizms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243   1 MKFGKTYMETMAdpsfpAEWRNGALEYKHLKKLINGVVAELESIGLGADVLRELLIRPEDDPASSTASSPKDKTRPLDSS 80
Cdd:pfam03105   1 MKFGKELEENLV-----PEWRDAYLDYKQLKKLIKKIQRELESTPPSSSPSSSDSGSAASPSDSTTSLPLRDPLSRSSSL 75

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1730128243  81 VDDRDSAIADESGNSSEQEEDSTgrpkKLTPAGKWISDFSVDMIRRASSPGDR 133
Cdd:pfam03105  76 DRAFGGLVPSPPSSSSSSSSDSS----SSSNSSSSSSSSSPSLLRRLPSESDD 124

Zinc finger, C3HC4 type (RING finger); The C3HC4 type zinc-finger (RING finger) is a cysteine-rich domain of 40 to 60 residues that coordinates two zinc ions, and has the consensus sequence: C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C where X is any amino acid. Many proteins containing a RING finger play a key role in the ubiquitination pathway.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1730128243 688 CAICTSVAWRPVR-LDCSHLFCLRCLVKLQRQGKDDCPLC 726
Cdd:pfam00097   1 CPICLEEPKDPVTlLPCGHLFCSKCIRSWLESGNVTCPLC 40

Domain found in Syg1, Pho81, XPR1, and related proteins; This region has been named the SPX domain after (Syg1, Pho81 and XPR1). This domain is found at the amino terminus of a variety of proteins. In the yeast protein Syg1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors Pho81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2. NUC-2 contains several ankyrin repeats. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with xenotropic and polytropic murine leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signaling and result in cell toxicity and death. The similarity between Syg1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, S. cerevisiae, and many other diverse organisms.

                          10        20        30
                  ....*....|....*....|....*....|...
gi 1730128243 552 EDFLRLNFALLDVKKFQRVNVEAARKILKKHDK 584
Cdd:cd14447   111 KELVESYSELEELERFVELNYTAFRKILKKYDK 143

SPX domain; We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organizms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 323 RIRLFIESPLPSDDEEGDEAANADSVSLSDDASSRKSIEKQIIE-------LPATPTRRFSTIPEDGPEG-------ETK 388
Cdd:pfam03105  31 KIQRELESTPPSSSPSSSDSGSAASPSDSTTSLPLRDPLSRSSSldrafggLVPSPPSSSSSSSSDSSSSsnsssssSSS 110

                          90       100       110       120       130       140       150       160
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 389 EQKVKRQSEIRRKRGTRSREIViPLTADTQFLDTLTHALQNLSNIQTHQHDNFMLETESLCSAVA-----RASSPYASKN 463
Cdd:pfam03105 111 SPSLLRRLPSESDDSSESYETT-PLDSEDEFFERLDSELNKVNKFYKEKEEEFLERLEALNKQLEalrdfRIKLIRESKS 189

                         170       180       190       200       210       220       230       240
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243 464 DLYVWREIFGLW-VEMQVFESQREKDRGELSIDESEarlKRFALELAKRGWIHDPNAPTPSKKGK--LVKLKIGSGPSSQ 540
Cdd:pfam03105 190 DLYRWREPFGLYsSDSSVFFSTSELDSGNSSESSVD---DEVEEELERNGWISPIKSKDKKKRPSeaLDKVKTPDRTLKG 266

                         250       260       270       280       290       300       310
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1730128243 541 GLQ----------NQTSATAIED-----FLRLNFALLDVKKFQRVNVEAARKILKKHDKRTALTASNDLRTFM 598
Cdd:pfam03105 267 FLDasrrdylnriNKVNLRKAKKklkkaFIELYRGLELLKSYSELNRTAFRKILKKFDKVTSLNASKDYMKEV 339

HC subclass of RING (RING-HC) finger and its variants; The RING finger is a specialized type of Zn-finger of 40 to 60 residues that binds two atoms of zinc. It is defined by the "cross-brace" motif that chelates zinc atoms by eight amino acid residues, typically Cys or His, arranged in a characteristic spacing. Canonical RING motifs have been categorized into two major subclasses, RING-HC (C3HC4-type) and RING-H2 (C3H2C3-type), according to their Cys/His content. There are also many variants of RING fingers. Some have a different Cys/His pattern. Some lack a single Cys or His residue at typical Zn ligand positions, especially, the fourth or eighth zinc ligand is prevalently exchanged for an Asp, which can chelate Zn in a RING finger as well. This family corresponds to the HC subclass of RING (RING-HC) fingers that are characterized by containing C3HC4-type canonical RING-HC fingers or noncanonical RING-HC finger variants, including C4C4-, C3HC3D-, C2H2C4-, and C3HC5-type modified RING-HC fingers. The canonical RING-HC finger has been defined as C-X2-C-X(9-39)-C-X(1-3)-H-X(2-3)-C-X2-C-X(4-48)-C-X2-C. It binds two Zn ions in a unique "cross-brace" arrangement, which distinguishes it from tandem zinc fingers and other similar motifs. RING-HC fingers can be found in a group of diverse proteins with a variety of cellular functions, including oncogenesis, development, viral replication, signal transduction, the cell cycle, and apoptosis. Many of them are ubiquitin-protein ligases (E3s) that serve as scaffolds for binding to ubiquitin-conjugating enzymes (E2s, also referred to as ubiquitin carrier proteins or UBCs) in close proximity to substrate proteins, which enables efficient transfer of ubiquitin from E2 to the substrates.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1730128243 686 YSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDDCPLC 726
Cdd:cd16449     1 LECPICLERLKDPVLLPCGHVFCRECIRRLLESGSIKCPIC 41

RING finger, HC subclass, found in RING finger protein 151 (RNF151) and similar proteins; RNF151 is a testis-specific RING finger protein that interacts with dysbindin, a synaptic and microtubular protein that binds brain snapin, a SNARE-binding protein that mediates intracellular membrane fusion in both neuronal and non-neuronal cells. Thus, it may be involved in acrosome formation of spermatids by interacting with multiple proteins participating in membrane biogenesis and microtubule organization. RNF151 contains a C3HC4-type RING finger domain, a putative nuclear localization signal (NLS), and a TNF receptor associated factor (TRAF)-type zinc finger domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVK-LQRQGKddCPLCRAP 729
Cdd:cd16547     2 DDLICSICHGVLRCPVRLSCSHIFCKKCILQwLKRQET--CPCCRKE 46

Variant RING finger, HC subclass (C4C4-type), found in retinoblastoma-binding protein 6 (RBBP6) and similar proteins; RBBP6, also known as proliferation potential-related protein, protein P2P-R, retinoblastoma-binding Q protein 1 (RBQ-1), or p53-associated cellular protein of testis (PACT), is a nuclear E3 ubiquitin-protein ligase involved in multiple processes, such as the control of gene expression, mitosis, cell differentiation, and cell apoptosis. It plays a role in both promoting and inhibiting apoptosis in many human cancers, including esophageal, lung, hepatocellular, and colon cancers, familial myeloproliferative neoplasms, as well as in human immunodeficiency virus-associated nephropathy (HIVAN). It functions as an Rb- and p53-binding protein that plays an important role in chaperone-mediated ubiquitination and possibly in protein quality control. It acts as a scaffold protein to promote the assembly of the p53/TP53-MDM2 complex, resulting in an increase of MDM2-mediated ubiquitination and degradation of p53/TP53, and leading to both apoptosis and cell growth. It is also a double-stranded RNA-binding protein that plays a role in mRNA processing by regulating the human polyadenylation machinery and modulating expression of mRNAs with AU-rich 3' untranslated regions (UTRs). Moreover, RBBP6 ubiquitinates and destabilizes the transcriptional repressor ZBTB38 that negatively regulates transcription and levels of the MCM10 replication factor on chromatin. Furthermore, RBBP6 is involved in tunicamycin-induced apoptosis by mediating protein kinase (PKR) activation. RBBP6 contains an N-terminal ubiquitin-like domain and a C4C4-type RING finger, whose overall folding is similar to that of the typical C3HC4-type RING-HC finger. RBBP6 interacts with chaperones Hsp70 and Hsp40 through its N-terminal ubiquitin-like domain. It promotes the ubiquitination of p53 by Hdm2 in an E4-like manner through its RING finger. It also interacts directly with the pro-proliferative transcription factor Y-box-binding protein-1 (YB-1) via its RING finger.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1730128243 684 DDYSCAICTSVAWRPVRLDC-SHLFCLRCLVKLQRQGKDDCPLCRAPgaVKSAD 736
Cdd:cd16620     2 DELKCPICKDLMKDAVLTPCcGNSFCDECIRTALLEEDFTCPTCKEP--DVSPD 53

Ring finger; E3 ubiquitin-protein ligase activity is intrinsic to the RING domain of c-Cbl and is likely to be a general function of this domain; Various RING fingers exhibit binding activity towards E2 ubiquitin-conjugating enzymes (Ubc' s)

                           10        20        30        40
                   ....*....|....*....|....*....|....*....|
gi 1730128243  688 CAICTSVAWR-PVRLDCSHLFCLRCLVKLQRQGKDDCPLC 726
Cdd:smart00184   1 CPICLEEYLKdPVILPCGHTFCRSCIRKWLESGNNTCPIC 40

SPX domain; We have named this region the SPX domain after SYG1, Pho81 and XPR1. This 180 residue long domain is found at the amino terminus of a variety of proteins. In the yeast protein SYG1, the N-terminus directly binds to the G-protein beta subunit and inhibits transduction of the mating pheromone signal. Similarly, the N-terminus of the human XPR1 protein binds directly to the beta subunit of the G-protein heterotrimer leading to increased production of cAMP. These findings suggest that all the members of this family are involved in G-protein associated signal transduction. The N-termini of several proteins involved in the regulation of phosphate transport, including the putative phosphate level sensors PHO81 from Saccharomyces cerevisiae and NUC-2 from Neurospora crassa, are also members of this family. The SPX domain of S. cerevisiae low-affinity phosphate transporters Pho87 and Pho90 auto-regulates uptake and prevents efflux. This SPX dependent inhibition is mediated by the physical interaction with Spl2 NUC-2 contains several ankyrin repeats pfam00023. Several members of this family are annotated as XPR1 proteins: the xenotropic and polytropic retrovirus receptor confers susceptibility to infection with murine xenotropic and polytropic leukaemia viruses (MLV). Infection by these retroviruses can inhibit XPR1-mediated cAMP signalling and result in cell toxicity and death. The similarity between SYG1, phosphate regulators and XPR1 sequences has been previously noted, as has the additional similarity to several predicted proteins, of unknown function, from Drosophila melanogaster, Arabidopsis thaliana, Caenorhabditis elegans, Schizosaccharomyces pombe, and Saccharomyces cerevisiae, and many other diverse organizms. In addition, given the similarities between XPR1 and SYG1 and phosphate regulatory proteins, it has been proposed that XPR1 might be involved in G-protein associated signal transduction and may itself function as a phosphate sensor.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1730128243   1 MKFGKTYMETMAdpsfpAEWRNGALEYKHLKKLINGVVAELESIGLGADVLRELLIRPEDDPASSTASSPKDKTRPLDSS 80
Cdd:pfam03105   1 MKFGKELEENLV-----PEWRDAYLDYKQLKKLIKKIQRELESTPPSSSPSSSDSGSAASPSDSTTSLPLRDPLSRSSSL 75

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1730128243  81 VDDRDSAIADESGNSSEQEEDSTgrpkKLTPAGKWISDFSVDMIRRASSPGDR 133
Cdd:pfam03105  76 DRAFGGLVPSPPSSSSSSSSDSS----SSSNSSSSSSSSSPSLLRRLPSESDD 124

RING finger, HC subclass, found in tripartite motif-containing protein TRIM65 and similar proteins; TRIM65 is an E3 ubiquitin-protein ligase that interacts with the innate immune receptor MDA5, enhancing its ability to stimulate interferon-beta signaling. It functions as a potential oncogenic protein that negatively regulates p53 through ubiquitination, providing insight into the development of novel approaches targeting TRIM65 for non-small cell lung carcinoma (NSCLC) treatment, and also overcoming chemotherapy resistance. Moreover, TRIM65 negatively regulates microRNA-driven suppression of mRNA translation by targeting TNRC6 proteins for ubiquitination and degradation. TRIM65 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*....
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQ---GKDDCPLCRAP 729
Cdd:cd16609     2 EELTCSICLGLYQDPVTLPCQHSFCRACIEDHWRQkdeGSFSCPECRAP 50

second RING finger, HC subclass, found in the LON peptidase N-terminal domain and RING finger protein family; The LON peptidase N-terminal domain and RING finger protein family includes LONRF1 (also known as RING finger protein 191 or RNF191), LONRF2 (also known as RING finger protein 192, RNF192, or neuroblastoma apoptosis-related protease), LONRF3 (also known as RING finger protein 127 or RNF127), which are characterized by containing two C3HC4-type RING-HC fingers, four tetratricopeptide (TPR) repeats, and an ATP-dependent protease La (LON) substrate-binding domain at the C-terminus. Their biological functions remain unclear. This model corresponds to the second RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1730128243 685 DYSCAICTSVAWRPVRLDCSHLFCLRCLVK-LQRQGKddCPLCRAP 729
Cdd:cd16514     1 DLECSLCLRLLYEPVTTPCGHTFCRACLERcLDHSPK--CPLCRTS 44

RING finger, HC subclass, found in RING finger protein 125 (RNF125); RNF125, also known as T-cell RING activation protein 1 (TRAC-1), is an E3 ubiquitin-protein ligase that is predominantly expressed in lymphoid cells, and functions as a positive regulator of T cell activation. It also down-modulates HIV replication and inhibits pathogen-induced cytokine production. It negatively regulates type I interferon signaling, which conjugates Lys(48)-linked ubiquitination to retinoic acid-inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. Further, RNF125 conjugates ubiquitin to melanoma differentiation-associated gene 5 (MDA5), a family protein of RIG-I. It thus acts as a negative regulator of RIG-I signaling, and is a direct target of miR-15b in the context of Japanese encephalitis virus (JEV) infection. Moreover, RNF125 binds to and ubiquitinates JAK1, prompting its degradation and inhibition of receptor tyrosine kinase (RTK) expression. It also negatively regulates p53 function through physical interaction and ubiquitin-mediated proteasome degradation. Mutations in RNF125 may lead to overgrowth syndromes (OGS). RNF125, together with three closely related proteins: RNF114, RNF138 and RNF166, forms a novel family of ubiquitin ligases with a C3HC4-type RING-HC finger, a C2HC-, and two C2H2-type zinc fingers, as well as a ubiquitin interacting motif (UIM). The UIM of RNF125 binds K48-linked poly-ubiquitin chains and is, together with the RING domain, required for auto-ubiquitination.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1730128243 685 DYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDDCPLCRA 728
Cdd:cd16542     1 NFDCAVCLEVLHQPVRTRCGHVFCRPCIATSLRNNTWTCPYCRA 44

RING finger, HC subclass, found in RING finger protein 146 (RNF146) and similar proteins; RNF146, also known as dactylidin, or iduna, is a cytoplasmic E3 ubiquitin-protein ligase that is responsible for PARylation-dependent ubiquitination (PARdU). It displays neuroprotective property due to its inhibition of Parthanatos, a PAR dependent cell death, via binding with Poly(ADP-ribose) (PAR). It also modulates PAR polymerase-1 (PARP-1)-mediated oxidative cell injury in cardiac myocytes. Moreover, RNF146 mediates tankyrase-dependent degradation of axin, thereby positively regulating Wnt signaling. It also facilitates DNA repair and protects against cell death induced by DNA damaging agents or gamma-irradiation by translocating to the nucleus after cellular injury and promoting the ubiquitination and degradation of various nuclear proteins involved in DNA damage repair. Furthermore, RNF146 is implicated in neurodegenerative disease and cancer development. It regulates the development and progression of non-small cell lung cancer (NSCLC) by enhancing cell growth, invasion, and survival. RNF146 contains an N-terminal C3HC4-type RING-HC finger followed by a WWE domain with a poly(ADP-ribose) (PAR) binding motif at the tail.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|...
gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKdDCPLCRAP 729
Cdd:cd16546     2 ECPICLQTCIHPVKLPCGHIFCYLCVKGVAWQSK-RCALCRQE 43

RING finger, HC subclass, found in tripartite motif-containing protein TRIM58 and similar proteins; TRIM58, also known as protein BIA2, is an erythroid E3 ubiquitin-protein ligase induced during late erythropoiesis. It binds and ubiquitinates the intermediate chain of the microtubule motor dynein (DYNC1LI1/DYNC1LI2), stimulating the degradation of the dynein holoprotein complex. It may participate in the erythroblast enucleation process through regulation of nuclear polarization. TRIM58 belongs to the C-IV subclass of TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|..
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVKL------QRQGKDDCPLCRAP 729
Cdd:cd16606     1 EEARCPVCLDFLQEPVSVDCGHSFCLRCISEFceksdsAQGGVYACPQCRGP 52

RING finger, HC subclass, found in RING finger and transmembrane domain-containing protein RNFT1, RNFT2, and similar proteins; Both RNFT1 and RNFT2 are multi-pass membrane proteins containing a C3HC4-type RING-HC finger. Their biological roles remain unclear.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCL-VKLQRQgkDDCPLCR 727
Cdd:cd16532     2 ICPICQDEFKDPVVLRCKHIFCEDCVsEWFERE--RTCPLCR 41

RING finger, HC subclass, found in tripartite motif-containing proteins, TRIM7, TRIM11 and TRIM27, and similar proteins; TRIM7, TRIM11 and TRIM27, closely related tripartite motif-containing proteins, belong to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox2, and a coiled coil region, as well as a SPRY/B30.2 domain positioned C-terminal to the RBCC domain. TRIM7, also known as glycogenin-interacting protein (GNIP) or RING finger protein 90 (RNF90), is an E3 ubiquitin-protein ligase that mediates c-Jun/AP-1 activation by Ras signalling. Its phosphorylation and activation by MSK1 in response to direct activation by the Ras-Raf-MEK-ERK pathway can stimulate TRIM7 E3 ubiquitin ligase activity in mediating Lys63-linked ubiquitination of the AP-1 coactivator RACO-1, leading to RACO-1 protein stabilization. Moreover, TRIM7 binds and activates glycogenin, the self-glucosylating initiator of glycogen biosynthesis. TRIM11, also known as protein BIA1, or RING finger protein 92 (RNF92), is an E3 ubiquitin-protein ligase involved in the development of the central nervous system. It is overexpressed in high-grade gliomas and promotes proliferation, invasion, migration and glial tumor growth. TRIM11 acts as a potential therapeutic target for congenital central hypoventilation syndrome (CCHS) by mediating the degradation of CCHS-associated polyalanine-expanded Phox2b. TRIM11 modulates the function of neurogenic transcription factor Pax6 through the ubiquitin-proteosome system, and thus plays an essential role for Pax6-dependent neurogenesis. It also binds to and destabilizes a key component of the activator-mediated cofactor complex (ARC105), humanin, a neuroprotective peptide against Alzheimer's disease-relevant insults, and further regulates ARC105 function in transforming growth factor beta (TGFbeta) signaling. Moreover, TRIM11 negatively regulates retinoic acid-inducible gene-I (RIG-I)-mediated interferon-beta (IFNbeta) production and antiviral activity by targeting TANK-binding kinase-1 (TBK1). It may contribute to the endogenous restriction of retroviruses in cells. It enhances N-tropic murine leukemia virus (N-MLV) entry by interfering with Ref1 restriction. It also suppresses the early steps of human immunodeficiency virus HIV-1 transduction, resulting in decreased reverse transcripts. TRIM27, also known as RING finger protein 76 (RNF76), RET finger protein (RFP), or zinc finger protein RFP, is a nuclear E3 ubiquitin-protein ligase that is highly expressed in testis and in various tumor cell lines. Expression of TRIM27 is associated with prognosis of colon and endometrial cancers. TRIM27 was first identified as a fusion partner of the RET receptor tyrosine kinase. It functions as a transcriptional repressor and associates with several proteins involved in transcriptional activity, such as enhancer of polycomb 1 (Epc1), a member of the Polycomb group proteins, and Mi-2beta, a main component of the nucleosome remodeling and deacetylase (NuRD) complex, and the cell cycle regulator retinoblastoma protein (RB1). It also interacts with HDAC1, leading to downregulation of thioredoxin binding protein 2 (TBP-2), which inhibits the function of thioredoxin. Moreover, TRIM27 mediates Pax7-induced ubiquitination of MyoD in skeletal muscle atrophy. In addition, it inhibits muscle differentiation by modulating serum response factor (SRF) and Epc1. TRIM27 promotes a non-canonical polyubiquitination of PTEN, a lipid phosphatase that catalyzes PtdIns(3,4,5)P3 (PIP3) to PtdIns(4,5)P2 (PIP2). It is an IKKepsilon-interacting protein that regulates IkappaB kinase (IKK) function and negatively regulates signaling involved in the antiviral response and inflammation. TRIM27 also forms a protein complex with MBD4 or MBD2 or MBD3, and thus plays an important role in the enhancement of transcriptional repression through MBD proteins in tumorigenesis, spermatogenesis, and embryogenesis. It is a component of an estrogen receptor 1 (ESR1) regulatory complex that is involved in estrogen receptor-mediated transcription in MCF-7 cells.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVKL--QRQGKDDCPLCRAP 729
Cdd:cd16594     4 EELTCPICLDYFTDPVTLDCGHSFCRACIARCweEPETSASCPQCRET 51

RING finger, HC subclass, found in Equid alphaherpesvirus 1 (Equine herpesvirus 1/EHV-1) regulatory protein and similar proteins; EHV-1 regulatory protein belongs to the Vmw110 (IPC0) protein family. It contains a typical C3HC4-type RING-HC finger and binds zinc stably.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1730128243 687 SCAICTSVAW-RPVRLDCSHLFCLRCLVKLQRQgKDDCPLCRAP 729
Cdd:cd23130     2 VCPICLDDPEdEAITLPCLHQFCYTCILRWLQT-SPTCPLCKTP 44

RING finger, HC subclass, found in Arabidopsis thaliana RING membrane-anchor proteins (AtRMAs) and similar proteins; AtRMAs, including AtRma1, AtRma2, and AtRma3, are endoplasmic reticulum (ER)-localized Arabidopsis homologs of human outer membrane of the ER-anchor E3 ubiquitin-protein ligase, RING finger protein 5 (RNF5). AtRMAs possess E3 ubiquitin ligase activity, and may play a role in the growth and development of Arabidopsis. The AtRMA1 and AtRMA3 genes are predominantly expressed in major tissues, such as cotyledons, leaves, shoot-root junction, roots, and anthers, while AtRMA2 expression is restricted to the root tips and leaf hydathodes. AtRma1 probably functions with the Ubc4/5 subfamily of E2. AtRma2 is likely involved in the cellular regulation of ABP1 expression levels through interacting with auxin binding protein 1 (ABP1). AtRMA proteins contain an N-terminal C3HC4-type RING-HC finger and a trans-membrane-anchoring domain in their extreme C-terminal region.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*
gi 1730128243 686 YSCAICTSVAWRPVRLDCSHLFCLRCLVK-LQRQGK-DDCPLCRA 728
Cdd:cd16745     1 FECNICLDLAQDPVVTLCGHLFCWPCLHKwLRRQSSqPECPVCKA 45

RING finger, HC subclass, found in Mus musculus tripartite motif-containing protein 43 (TRIM43) and similar propteins; This subfamily includes TRIM43A, TRIM43B and TRIM43C, which are expressed specifically in mouse preimplantation embryos. They contain a typical C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*...
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDD--CPLCRAP 729
Cdd:cd23133     2 ETLTCSICQGIFMNPVYLRCGHKFCEACLLLFQEDIKFPayCPMCRQP 49

RING finger, HC subclass, found in tripartite motif-containing protein 31 (TRIM31) and similar proteins; TRIM31 is an E3 ubiquitin-protein ligase that primarily localizes to the cytoplasm, but is also associated with the mitochondria. It can negatively regulate cell proliferation and may be a potential biomarker of gastric cancer as it is overexpressed from the early stage of gastric carcinogenesis. TRIM31 is downregulated in non-small cell lung cancer and serves as a potential tumor suppressor. It interacts with p52 (Shc) and inhibits Src-induced anchorage-independent growth. TRIM31 belongs to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by an N-terminal RBCC (RING, Bbox, and coiled coil) domain, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as an uncharacterized region positioned C-terminal to the RBCC domain.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQ--GKDDCPLC 726
Cdd:cd16582     3 ICPICLDILQKPVTIDCGHNFCLQCITQIGETscGFFKCPLC 44

RING finger, HC subclass, found in RING finger protein 170 (RNF170) and similar proteins; RNF170, also known as putative LAG1-interacting protein, is an endoplasmic reticulum (ER) membrane-bound E3 ubiquitin-protein ligase that mediates ubiquitination-dependent degradation of type-I inositol 1,4,5-trisphosphate (IP3) receptors (ITPR1) via the endoplasmic-reticulum-associated protein degradation (ERAD) pathway. A point mutation (arginine to cysteine at position 199) in the RNF170 gene is linked with autosomal-dominant sensory ataxia (ADSA), a disease characterized by neurodegeneration in the posterior columns of the spinal cord. RNF170 contains a C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1730128243 685 DYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGK----DDCPLCR 727
Cdd:cd16553     1 DMECPICLQDARFPVETNCGHLFCGPCIITYWRHGSwlgaVSCPVCR 47

Ring finger domain;

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....
gi 1730128243 687 SCAICT---SVAWRPVRLDCSHLFCLRCLVKLQRQGKDdCPLCR 727
Cdd:pfam13639   2 ECPICLeefEEGDKVVVLPCGHHFHRECLDKWLRSSNT-CPLCR 44

RING finger, HC subclass, found in tripartite motif-containing protein 47 (TRIM47) and similar proteins; TRIM47, also known as gene overexpressed in astrocytoma protein (GOA) or RING finger protein 100 (RNF100), belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain. It plays an important role in the process of dedifferentiation that is associated with astrocytoma tumorigenesis. This subfamily also includes RING finger protein 135 (RNF135). RNF135, also known as RIG-I E3 ubiquitin ligase (REUL) or Riplet, is a widely expressed E3 ubiquitin-protein ligase that consists of an N-terminal C3HC4-type RING-HC finger and C-terminal B30.2/SPRY and PRY motifs, but lacks the B-box and coiled-coil domains that are also typically present in TRIM proteins. RNF135 serves as a specific retinoic acid-inducible gene-I (RIG-I)-interacting protein that ubiquitinates RIG-I and specifically stimulates RIG-I-mediated innate antiviral activity to produce antiviral type-I interferon (IFN) during the early phase of viral infection. It also has been identified as a bio-marker and therapy target of glioblastoma. It associates with the ERK signal transduction pathway and plays a role in glioblastoma cell proliferation, migration and cell cycle.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCLVKL---QRQGKDDCPLCRAP 729
Cdd:cd16604     2 SCPICLDLLKDPVTLPCGHSFCMGCLGALwgaGRGGRASCPLCRQT 47

RING finger, HC subclass, found in ubiquitin-like PHD and RING finger domain-containing proteins, UHRF1 and UHRF2, and similar proteins; UHRF1 is a unique chromatin effector protein that integrates the recognition of both histone PTMs and DNA methylation. It is essential for cell proliferation and plays a critical role in the development and progression of many human carcinomas, such as laryngeal squamous cell carcinoma (LSCC), gastric cancer (GC), esophageal squamous cell carcinoma (ESCC), colorectal cancer, prostate cancer, and breast cancer. UHRF1 acts as a transcriptional repressor through its binding to histone H3 when it is unmodified at Arg2. Its overexpression in human lung fibroblasts results in downregulation of expression of the tumor suppressor pRB. It also plays a role in transcriptional repression of the cell cycle regulator p21. Moreover, UHRF1-dependent repression of transcription factors can facilitate the G1-S transition. It interacts with Tat-interacting protein of 60 kDa (TIP60) and induces degradation-independent ubiquitination of TIP60. It is also an N-methylpurine DNA glycosylase (MPG)-interacting protein that binds MPG in a p53 status-independent manner in the DNA base excision repair (BER) pathway. In addition, UHRF1 functions as an epigenetic regulator that is important for multiple aspects of epigenetic regulation, including maintenance of DNA methylation patterns and recognition of various histone modifications. UHRF2 was originally identified as a ubiquitin ligase acting as a small ubiquitin-like modifier (SUMO) E3 ligase that enhances zinc finger protein 131 (ZNF131) SUMOylation, but does not enhance ZNF131 ubiquitination. It also ubiquitinates PCNP, a PEST-containing nuclear protein. Moreover, UHRF2 functions as a nuclear protein involved in cell-cycle regulation and has been implicated in tumorigenesis. It interacts with cyclins, CDKs, p53, pRB, PCNA, HDAC1, DNMTs, G9a, methylated histone H3 lysine 9, and methylated DNA. It interacts with the cyclin E-CDK2 complex, ubiquitinates cyclins D1 and E1, induces G1 arrest, and is involved in the G1/S transition regulation. Furthermore, UHRF2 is a direct transcriptional target of the transcription factor E2F-1 in the induction of apoptosis. It recruits HDAC1 and binds to methyl-CpG. UHRF2 also participates in the maturation of Hepatitis B virus (HBV) by interacting with the HBV core protein and promoting its degradation. Both UHRF1 and UHRF2 contain an N-terminal ubiquitin-like domain (UBL), a tandem Tudor domain (TTD), a plant homeodomain (PHD) finger, a SET- and RING-associated (SRA) domain, and a C-terminal C3HC4-type RING-HC finger.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 1730128243 686 YSCAICTSVAWRPVRLDCSHLFCLRClvkLQRQGKDD---CPLCRA 728
Cdd:cd16613     1 FTCICCQELVYKPITTPCKHNICKSC---LQRSFKAEvytCPACRH 43

RING finger, HC subclass, found in tripartite motif-containing protein 40 (TRIM40) and similar proteins; TRIM40, also known as probable E3 NEDD8-protein ligase or RING finger protein 35 (RNF35), is highly expressed in the gastrointestinal tract including the stomach, small intestine, and large intestine. It enhances neddylation of inhibitor of nuclear factor kappaB kinase subunit gamma (IKKgamma), inhibits the activity of nuclear factor-kappaB (NF-kappaB)-mediated transcription, and thus prevents inflammation-associated carcinogenesis in the gastrointestinal tract. TRIM40 belongs to the C-V subclass of the TRIM (tripartite motif) family of proteins that are defined by an N-terminal RBCC (RING, Bbox, and coiled coil) domain, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as an uncharacterized region positioned C-terminal to the RBCC domain.

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                  ....*....|....*....|....*....|....*....|....*.
gi 1730128243 688 CAICTSVAWRPVRLDCSHLFCLRCLV----KLQRQGKDDCPLCRAP 729
Cdd:cd16583     8 CPICQEPLKEAVSTDCGHLFCRMCLTqhakKASASGVFSCPVCRKP 53

RING finger, HC subclass, found in RING finger protein RNF5, RNF185 and similar proteins; RNF5 and RNF185 are E3 ubiquitin-protein ligases that are anchored to the outer membrane of the endoplasmic reticulum (ER). RNF5 acts at early stages of cystic fibrosis (CF) transmembrane conductance regulator (CFTR) biosynthesis, and functions as a target for therapeutic modalities to antagonize mutant CFTR proteins in CF patients carrying the F508del allele. RNF185 controls the degradation of CFTR and CFTR F508del allele in a RING- and proteasome-dependent manner, but does not control that of other classical endoplasmic reticulum-associated degradation (ERAD) model substrates. Moreover, both RNF5 and RNF185 play important roles in cell adhesion and migration through the modulation of cell migration by ubiquitinating paxillin. Arabidopsis thaliana RING membrane-anchor proteins (AtRMAs) are also included in this family. They possess E3 ubiquitin-protein ligase activity and may play a role in the growth and development of Arabidopsis. All members of this family contain a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....
gi 1730128243 686 YSCAICTSVAWRPVRLDCSHLFCLRCLVK-LQRQGKD-DCPLCR 727
Cdd:cd16534     1 FECNICLDTASDPVVTMCGHLFCWPCLYQwLETRPDRqTCPVCK 44

RING finger, HC subclass, found in tripartite motif-containing protein 26 (TRIM26) and similar proteins; TRIM26, also known as acid finger protein (AFP), RING finger protein 95 (RNF95), or zinc finger protein 173 (ZNF173), is an E3 ubiquitin-protein ligase that negatively regulates interferon-beta production and antiviral response through polyubiquitination and degradation of nuclear transcription factor IRF3. It functions as an important regulator for RNA virus-triggered innate immune response by bridging TBK1 to NEMO (NF-kappaB essential modulator, also known as IKKgamma) and mediating TBK1 activation. It also acts as a novel tumor suppressor of hepatocellular carcinoma by regulating cancer cell proliferation, colony forming ability, migration, and invasion. TRIM26 belongs the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, a B-box, and two coiled coil domains, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|
gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLV----KLQRQGKDDCPLCRAP 729
Cdd:cd16598     3 EEVTCSICLDYLRDPVTIDCGHNFCRSCITdycpISGGHERPVCPLCRKP 52

RING finger, HC subclass, found in really interesting new gene proteins RING1, RING2 and similar proteins; RING1, also known as polycomb complex protein RING1, RING finger protein 1 (RNF1), or RING finger protein 1A (RING1A), is a transcriptional repressor that is associated with the Polycomb group (PcG) protein complex involved in stable repression of gene activity. RING2, also known as huntingtin-interacting protein 2-interacting protein 3, HIP2-interacting protein 3, protein DinG, RING finger protein 1B (RING1B), RING finger protein 2 (RNF2), or RING finger protein BAP-1, is an E3 ubiquitin-protein ligase that interacts with both nucleosomal DNA and an acidic patch on histone H4 to achieve the specific monoubiquitination of K119 on histone H2A (H2AK119ub), thereby playing a central role in histone code and gene regulation. Both RING1 and RING2 are core components of polycomb repressive complex 1 (PRC1) that functions as an E3-ubuiquitin ligase transferring the mono-ubuiquitin mark to the C-terminal tail of Histone H2A at K118/K119. PRC1 is also capable of chromatin compaction, a function not requiring histone tails, and this activity appears important in gene silencing. RING2 acts as the main E3 ubiquitin ligase on histone H2A of the PRC1 complex, while RING1 may rather act as a modulator of RNF2/RING2 activity. Members of this family contain a C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....*....|....*...
gi 1730128243 685 DYSCAICTSVAWRP-VRLDCSHLFCLRCLVKLQRQGKDDCPLCRAPGAVKSADRHNMN 741
Cdd:cd16531     1 ELMCPICLGIIKNTmTVKECLHRFCAECIEKALRLGNKECPTCRKHLPSRRSLRPDPN 58

RING finger, HC subclass, found in Saccharomyces cerevisiae radiation sensitivity protein 18 (RAD18) and similar proteins; RAD18, also called RING-type E3 ubiquitin transferase RAD18, acts as a postreplication repair E3 ubiquitin-protein ligase that associates with the E2 ubiquitin conjugating enzyme UBC2/RAD6 to form the UBC2-RAD18 ubiquitin ligase complex involved in postreplicative repair (PRR) of damaged DNA. The UBC2-RAD18 complex cooperates with RAD5 and the UBC13-MMS2 dimer to attach mono-ubiquitin chains on 'Lys-164' of POL30, which is necessary for PRR. The UBC2-RAD18 complex is also involved in prevention of spontaneous mutations caused by 7,8-dihydro-8-oxoguanine. RAD18 is an E3 RING-finger protein belonging to the UBC2/RAD6 epistasis group. It contains a typical C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|...
gi 1730128243 688 CAICTSVAWRPVRLDCSHLFCLRCLVK-LQRQGKddCPLCRAP 729
Cdd:cd23148     6 CHICKDLLKAPMRTPCNHTFCSFCIRThLNNDAR--CPLCKAE 46

RING finger, HC subclass, found in Casitas B-lineage lymphoma (Cbl) proteins; The Cbl adaptor protein family contains a small class of RING-type E3 ubiquitin ligases with oncogenic activity, which is represented by three mammalian members, c-Cbl, Cbl-b and Cbl-c, as well as two invertebrate Cbl-family proteins, D-Cbl in Drosophila and Sli-1 in C. elegans. Cbl proteins function as potent negative regulators of various signaling cascades in a wide range of cell types. They play roles in ubiquitinating activated tyrosine kinases and targeting them for degradation. D-Cbl associates with the Drosophila epidermal growth factor receptor (EGFR) and overexpression of D-Cbl in the eye of Drosophila embryos inhibits EGFR-dependent photoreceptor cell development. Sli-1 is a negative regulator of the Let-23 receptor tyrosine kinase, an EGFR homolog, in vulva development. Cbl proteins in this subfamily consist of a highly conserved N-terminal half that includes a tyrosine-kinase-binding domain (TKB, also known as the phosphotyrosine binding PTB domain, composed of a four helix-bundle, a Ca2+ binding EF-hand and a highly variant SH2 domain) and a C3HC4-type RING-HC finger, both of which are required for Cbl-mediated downregulation of RTKs, and a divergent C-terminal region.

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                  ....*....|....*....|....*....|....*....|.
gi 1730128243 688 CAICTSVAwRPVRLD-CSHLFCLRCLVKLQRQGKDDCPLCR 727
Cdd:cd16502     4 CKICAEND-KDVRIEpCGHLLCTPCLTSWQDSDGQTCPFCR 43

RING finger, H2 subclass, found in 43 kDa receptor-associated protein of the synapse (Rapsyn) and similar proteins; Rapsyn, also known as acetylcholine receptor (AChR)-associated 43 kDa protein or RING finger protein 205 (RNF205), is a 43 kDa postsynaptic protein that plays an essential role in the clustering and maintenance of AChR in the postsynaptic membrane of the motor endplate. AChRs enable the transport of rapsyn from the Golgi complex to the plasma membrane through a molecule-specific interaction. Rapsyn also mediates subsynaptic anchoring of protein kinase A (PKA) type I in close proximity to the postsynaptic membrane, which is essential for synapse maintenance. Its mutations in humans cause endplate AChR deficiency and myasthenic syndrome. Rapsyn contains an N-terminal myristoylation signal required for membrane association, seven tetratricopeptide repeats (TPRs) that subserve rapsyn self-association, a coiled-coil domain responsible for the binding of determinants within the long cytoplasmic loop of each AChR subunit, a C3H2C3-type RING-H2 finger that binds to the cytoplasmic domain of beta-dystroglycan and to S-NRAP and links rapsyn to the subsynaptic cytoskeleton, and a serine phosphorylation site.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*..
gi 1730128243 685 DYSCAIC-TSVAWRPVRLD---CSHLFCLRCLVKLQRQGKDDCPLCR 727
Cdd:cd16478     1 ELFCGMCgESIGEKNEQLQalpCSHIFHLKCLQTNLRGGTRGCPNCR 47

RING finger, HC subclass, found in Ret finger protein-like 4B (RFPL4B) and similar proteins; RFPL4B, also called RING finger protein 211 (RNF211), is an uncharacterized RING finger protein containing a typical C3HC4-type RING-HC finger.

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                  ....*....|....*....|....*....|....*....|....
gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDD---CPLCR 727
Cdd:cd16623    10 TCPICLDFFSHPISLSCAHIFCFDCIQKWMTKREDSiltCPLCR 53

RING finger, HC subclass, found in Saccharomyces cerevisiae increased recombination centers protein 20 (IRC20) and similar proteins; IRC20 is an uncharacterized ATP-dependent helicase that is probably involved in a pathway contributing to genomic integrity. IRC20 contains a typical C3HC4-type RING-HC finger.

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gi 1730128243 685 DYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQgKDDCPLCR 727
Cdd:cd23135     3 KLSCSICFSEIRSGAILKCGHFFCLSCIASWLRE-KSTCPLCK 44

RING finger, HC subclass, found in RING finger protein 168 (RNF168) and similar proteins; RNF168 is an E3 ubiquitin-protein ligase that promotes noncanonical K27 ubiquitination to signal DNA damage. It, together with RNF8, functions as a DNA damage response (DDR) factor that promotes a series of ubiquitylation events on substrates, such as H2A and H2AX with H2AK13/15 ubiquitylation, facilitates recruitment of repair factors p53-binding protein 1 (53BP1) or the RAP80-BRCA1 complex to sites of double-strand breaks (DSBs), and inhibits homologous recombination (HR) in cells deficient in the tumor suppressor BRCA1. RNF168 also promotes H2A neddylation, which antagonizes ubiquitylation of H2A and regulates DNA damage repair. Moreover, RNF168 forms a functional complex with RAD6A or RAD6B during the DNA damage response. RNF168 contains an N-terminal C3HC4-type RING-HC finger that catalyzes H2A-K15ub and interacts with H2A, and two MIU (motif interacting with ubiquitin) domains responsible for the interaction with K63 linked poly-ubiquitin.

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gi 1730128243 688 CAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDDCPLCR 727
Cdd:cd16550     3 CPICLEILVEPVTLPCNHTLCMPCFQSTVEKASLCCPLCR 42

RING finger, HC subclass, found in bifunctional apoptosis regulator (BAR); BAR, also known as RING finger protein 47, was originally identified as an inhibitor of Bax-induced apoptosis. It participates in the block of apoptosis induced by TNF-family death receptors (extrinsic pathway) and mitochondria-dependent apoptosis (intrinsic pathway). BAR is predominantly expressed by neurons in the central nervous system and is involved in the regulation of neuronal survival. It is an endoplasmic reticulum (ER)-associated RING-type E3 ubiquitin ligase that interacts with BI-1 protein and post-translationally regulates its stability, as well as functioning in ER stress. BAR contains an N-terminal C3HC4-type RING-HC finger, a SAM domain, a coiled-coil domain, and a C-terminal transmembrane (TM) domain. This model corresponds to the RING-HC finger responsible for the binding of ubiquitin conjugating enzymes (E2s).

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gi 1730128243 685 DYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQG-KDDCPLCR 727
Cdd:cd16497     1 EFLCHCCYDLLVNPTTLNCGHSFCRHCLALWWKSSkKTECPECR 44

RING finger, HC subclass, found in checkpoint with forkhead and RING finger domains protein (CHFR); CHFR, also known as RING finger protein 196 (RNF196), is a checkpoint protein that delays entry into mitosis in response to stress. It functions as an E3 ubiquitin ligase that ubiquitinates and degrades its target proteins, such as Aurora-A, Plk1, Kif22, and PARP-1, which are critical for proper mitotic transitions. It also plays an important role in cell cycle progression and tumor suppression, and is negatively regulated by SUMOylation-mediated proteasomal ubiquitylation. Moreover, CHFR is involved in the early stage of the DNA damage response, which mediates the crosstalk between ubiquitination and poly-ADP-ribosylation. CHFR contains a fork head associated (FHA) domain and a C3HC4-type RING-HC finger.

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gi 1730128243 684 DDYSCAICTSVAWRPVRLD-CSHLFCLRCLVKLQRQGKDDCPLCRAPgaVKSADRHN 739
Cdd:cd16503     1 ENLTCSICQDLLHDCVSLQpCMHNFCAACYSDWMERSNTECPTCRAT--VQRVNKNH 55

RING finger, HC subclass, found in tripartite motif-containing protein 39 (TRIM39) and similar proteins; TRIM39, also known as RING finger protein 23 (RNF23) or testis-abundant finger protein, is an E3 ubiquitin-protein ligase that plays a role in controlling DNA damage-induced apoptosis through inhibition of the anaphase promoting complex (APC/C), a multiprotein ubiquitin ligase that controls multiple cell cycle regulators, including cyclins, geminin, and others. TRIM39 also functions as a regulator of several key processes in the proliferative cycle. It directly regulates p53 stability. It modulates cell cycle progression and DNA damage responses via stabilizing p21. Moreover, TRIM39 negatively regulates the nuclear factor kappaB (NFkappaB)-mediated signaling pathway through stabilization of Cactin, an inhibitor of NFkappaB- and Toll-like receptor (TLR)-mediated transcription, which is induced by inflammatory stimulants such as tumor necrosis factor alpha. Furthermore, TRIM39 is a MOAP-1-binding protein that can promote apoptosis signaling through stabilization of MOAP-1 via the inhibition of its poly-ubiquitination process. TRIM39 belongs to the C-IV subclass of the TRIM (tripartite motif) family of proteins that are defined by their N-terminal RBCC (RING, Bbox, and coiled coil) domains, including three consecutive zinc-binding domains, a C3HC4-type RING-HC finger, Bbox1 and Bbox2, and a coiled coil region, as well as a B30.2/SPRY (SplA and ryanodine receptor) domain positioned C-terminal to the RBCC domain.

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gi 1730128243 687 SCAICTSVAWRPVRLDCSHLFCLRCLVKLQRQGKDD--CPLC 726
Cdd:cd16601     3 SCSLCKEYLKDPVIIECGHNFCRACITRFWEELDGDfpCPQC 44

Modified RING finger, HC subclass (C3HC3D-type), found in ligand of numb protein X 2 (LNX2); LNX2, also known as numb-binding protein 2, or PDZ domain-containing RING finger protein 1 (PDZRN1), is a PDZ domain-containing RING-type E3 ubiquitin ligase responsible for the ubiquitination and degradation of Numb, a component of the Notch signaling pathway that functions in the specification of cell fates during development and is known to control cell numbers during neurogenesis in vertebrates. It interacts with contactin-associated protein 4 (Caspr4, also known as CNTNAP4) in a PDZ domain-dependent manner, which modulates the proliferation and neuronal differentiation of neural progenitor cells (NPCs). LNX2 contains an N-terminal modified C3HC3D-type RING-HC finger, a NPAF motif for Numb/ Numblike-LNX interaction, and four PDZ domains necessary for the binding of substrates, including ErbB2, RhoC, the presynaptic protein CAST, the melanoma/cancer-testis antigen MAGEB18 and several proteins associated with cell junctions, such as JAM4 and the Coxsackievirus and adenovirus receptor (CAR).

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gi 1730128243 684 DDYSCAICTSVAWRPVRLDCSHLFCLRCLVKLQrQGKDDCPLCRA 728
Cdd:cd16780     2 DDLVCHICLQPLLQPLDTPCGHTFCFKCLRNFL-QEKDFCPLDRK 45