phosphoacceptor receiver (REC) domain of response regulators (RRs) and pseudo response regulators (PRRs); Two-component systems (TCSs) involving a sensor and a response regulator are used by bacteria to adapt to changing environments. Processes regulated by two-component systems in bacteria include sporulation, pathogenicity, virulence, chemotaxis, and membrane transport. Response regulators (RRs) share the common phosphoacceptor REC domain and different effector/output domains such as DNA, RNA, ligand-binding, protein-binding, or enzymatic domains. Response regulators regulate transcription, post-transcription or post-translation, or have functions such as methylesterases, adenylate or diguanylate cyclase, c-di-GMP-specific phosphodiesterases, histidine kinases, serine/threonine protein kinases, and protein phosphatases, depending on their output domains. The function of some output domains are still unknown. TCSs are found in all three domains of life - bacteria, archaea, and eukaryotes, however, the presence and abundance of particular RRs vary between the lineages. Archaea encode very few RRs with DNA-binding output domains; most are stand-alone REC domains. Among eukaryotes, TCSs are found primarily in protozoa, fungi, algae, and green plants. REC domains function as phosphorylation-mediated switches within RRs, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  26 LLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVIgLSG-- 103
Cdd:cd00156    1 LIVDDDPAIRELLKSLLEREGYEVDTAADGEEALELLREERPDLVLLDLMMPGMDGLELLRKLRELPPDIPVIV-LTAka 79

                         90       100
                 ....*....|....*....|
gi 502831305 104 DPGMMAEAMAAGADAFMEKP 123
Cdd:cd00156   80 DEEDAVRALELGADDYLVKP 99

DNA-binding transcriptional activator KdpE; Provisional

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 502831305  24 TVLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIK 89
Cdd:PRK10529   3 NVLIVEDEQAIRRFLRTALEGDGMRVFEAETLQRGLLEAATRKPDLIILDLGLPDGDGIEFIRDLR 68

DNA-binding response regulator DpiB of citrate/malate metabolism [Transcription, Signal transduction mechanisms];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  23 LTVLLVEDSRFASEAVRLLCLRSG--ARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPaVIG 100
Cdd:COG4565    4 IRVLIVEDDPMVAELLRRYLERLPgfEVVGVASSGEEALALLAEHRPDLILLDIYLPDGDGLELLRELRARGPDVD-VIV 82

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|
gi 502831305 101 LSG--DPGMMAEAMAAGADAFMEKPLdSLVAFQARVLSVL 138
Cdd:COG4565   83 ITAarDPETVREALRAGVVDYLIKPF-TFERLREALERYL 121

phosphoacceptor receiver (REC) domain of response regulators (RRs) and pseudo response regulators (PRRs); Two-component systems (TCSs) involving a sensor and a response regulator are used by bacteria to adapt to changing environments. Processes regulated by two-component systems in bacteria include sporulation, pathogenicity, virulence, chemotaxis, and membrane transport. Response regulators (RRs) share the common phosphoacceptor REC domain and different effector/output domains such as DNA, RNA, ligand-binding, protein-binding, or enzymatic domains. Response regulators regulate transcription, post-transcription or post-translation, or have functions such as methylesterases, adenylate or diguanylate cyclase, c-di-GMP-specific phosphodiesterases, histidine kinases, serine/threonine protein kinases, and protein phosphatases, depending on their output domains. The function of some output domains are still unknown. TCSs are found in all three domains of life - bacteria, archaea, and eukaryotes, however, the presence and abundance of particular RRs vary between the lineages. Archaea encode very few RRs with DNA-binding output domains; most are stand-alone REC domains. Among eukaryotes, TCSs are found primarily in protozoa, fungi, algae, and green plants. REC domains function as phosphorylation-mediated switches within RRs, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  26 LLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVIgLSG-- 103
Cdd:cd00156    1 LIVDDDPAIRELLKSLLEREGYEVDTAADGEEALELLREERPDLVLLDLMMPGMDGLELLRKLRELPPDIPVIV-LTAka 79

                         90       100
                 ....*....|....*....|
gi 502831305 104 DPGMMAEAMAAGADAFMEKP 123
Cdd:cd00156   80 DEEDAVRALELGADDYLVKP 99

DNA-binding response regulator, OmpR family, contains REC and winged-helix (wHTH) domain [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  23 LTVLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPaVIGLS 102
Cdd:COG0745    2 PRILVVEDDPDIRELLADALEREGYEVDTAADGEEALELLEEERPDLILLDLMLPGMDGLEVCRRLRARPSDIP-IIMLT 80

                 .
gi 502831305 103 G 103
Cdd:COG0745   81 A 81

DNA-binding response regulator, ActR/RegA family, consists of REC and Fis-type HTH domains [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  24 TVLLVED-SRFASEAVRLLcLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVIgLS 102
Cdd:COG4567    6 SLLLVDDdEAFARVLARAL-ERRGFEVTTAASVEEALALLEQAPPDYAVLDLRLGDGSGLDLIEALRERDPDARIVV-LT 83

                 .
gi 502831305 103 G 103
Cdd:COG4567   84 G 84

Two-component response regulator, PleD family, consists of two REC domains and a diguanylate cyclase (GGDEF) domain [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  23 LTVLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKA-AGPGSPAVIGL 101
Cdd:COG3706    2 ARILVVDDDPTNRKLLRRLLEAAGYEVVEAADGEEALELLQEHRPDLILLDLEMPDMDGLELCRRLRAdPRTADIPIIFL 81

                         90       100       110
                 ....*....|....*....|....*....|....*
gi 502831305 102 SG--DPGMMAEAMAAGADAFMEKPLDSLVaFQARV 134
Cdd:COG3706   82 TAldDEEDRARALEAGADDYLTKPFDPEE-LLARV 115

phosphoacceptor receiver (REC) domain of type 4 fimbriae expression regulatory protein PilR and similar proteins; Pseudomonas aeruginosa PilR is the response regulator of the PilS/PilR two-component regulatory system (PilSR TCS) that acts in conjunction with sigma-54 to regulate the expression of type 4 pilus (T4P) major subunit PilA. In addition, the PilSR TCS regulates flagellum-dependent swimming motility and pilus-dependent twitching motility. PilR contains an N-terminal REC domain, a central sigma-54 interaction domain, and a C-terminal Fis-type helix-turn-helix DNA-binding domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 502831305  25 VLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSP-AVI 99
Cdd:cd19926    1 VLVVDDEPDIRELLEITLGRMGLDVRSARNVKEARELLASEPYDLCLTDMRLPDGSGLELVQHIQQRLPQTPvAVI 76

phosphoacceptor receiver (REC) domain of KdpE-like OmpR family response regulators; KdpE is a component of the KdpD/KdpE two-component system (TCS) and is activated when histidine kinase KdpD senses a drop in external K+ concentration or upshift in ionic osmolarity, resulting in the expression of a heterooligomeric transporter KdpFABC. In addition, the KdpD/KdpE TCS is also an adaptive regulator involved in the virulence and intracellular survival of pathogenic bacteria. KdpE is a member of the OmpR family of DNA-binding response regulators that contain REC and winged helix-turn-helix (wHTH) DNA-binding output effector domains. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 502831305  25 VLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIK 89
Cdd:cd17620    1 ILVIEDEPQIRRFLRTALEAHGYRVFEAETGQEGLLEAATRKPDLIILDLGLPDMDGLEVIRRLR 65

phosphoacceptor receiver (REC) domain of PmrA-like OmpR family response regulators; This subfamily contains various OmpR family response regulators including PmrA, BasR, QseB, tctD, and RssB, which are components of two-component regulatory systems (TCSs). The PmrA/PmrB TCS controls transcription of genes that are involved in lipopolysaccharide modification in the outer membrane of bacteria, increasing bacterial resistance to host-derived antimicrobial peptides. The BasS/BasR TCS functions as an iron- and zinc-sensing transcription regulator. The QseB/QseC TCS activates the flagella regulon by activating transcription of FlhDC. The RssA/RssB TCS regulates swarming behavior in Serratia marcescens. OmpR family DNA-binding response regulators contain N-terminal receiver (REC) and C-terminal DNA-binding winged helix-turn-helix effector domains. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 502831305  25 VLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVI 99
Cdd:cd17624    1 ILLVEDDALLGDGLKTGLRKAGYAVDWVRTGAEAEAALASGPYDLVILDLGLPDGDGLDLLRRWRRQGQSLPVLI 75

phosphoacceptor receiver (REC) domain of MtPhoP-like OmpR family response regulators; Mycobacterium tuberculosis PhoP (MtPhoP) is part of the PhoP/PhoR two-component system that is involved in phosphate control by stimulating expression of genes involved in scavenging, transport and mobilization of phosphate, and repressing the utilization of nitrogen sources. Also included in this subfamily is Mycobacterium tuberculosis transcriptional regulatory protein TcrX, part of the two-component regulatory system TcrY/TcrX that may be involved in virulence. Members of this subfamily belong to the OmpR family of DNA-binding response regulators, which are characterized by a REC domain and a winged helix-turn-helix (wHTH) DNA-binding output effector domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 502831305  24 TVLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAV 98
Cdd:cd17615    1 RVLVVDDEPNITELLSMALRYEGWDVETAADGAEALAAAREFRPDAVVLDIMLPDMDGLEVLRRLRADGPDVPVL 75

second phosphoacceptor receiver (REC) domain of Dictyostelium discoideum hybrid signal transduction histidine kinase D and similar domains; Dictyostelium discoideum hybrid signal transduction histidine kinase D (DhkD) is a large protein that contains two histidine kinase (HK) and two REC domains on the intracellular side of a single pass transmembrane domain, and extracellular PAS and PAC domains that likely are involved in ligand binding. This model represents the second REC domain and similar domains. DhkD activates the cAMP phosphodiesterase RegA to ensure proper prestalk and prespore patterning, tip formation, and the vertical elongation of the mound into a finger, in Dictyostelium discoideum. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  25 VLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPG-SPAVIGLSG 103
Cdd:cd17580    1 ILVVDDNEDAAEMLALLLELEGAEVTTAHSGEEALEAAQRFRPDVILSDIGMPGMDGYELARRLRELPWLaNTPAIALTG 80

phosphoacceptor receiver (REC) domain of photosynthetic apparatus regulatory protein RegA; Rhodobacter sphaeroides RegA, also called response regulator PrrA, is the DNA binding regulatory protein of a redox-responsive two-component regulatory system RegB/RegA that is involved in transactivating anaerobic expression of the photosynthetic apparatus. It contains a REC domain and a DNA-binding helix-turn-helix output domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  24 TVLLVEDSR-FASEAVRLLcLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVIgLS 102
Cdd:cd17563    2 SLLLVDDDEvFAERLARAL-ERRGFEVETAHSVEEALALAREEKPDYAVLDLRLGGDSGLDLIPPLRALQPDARIVV-LT 79

                 .
gi 502831305 103 G 103
Cdd:cd17563   80 G 80

Two-component response regulator, AmiR/NasT family, consists of REC and RNA-binding antiterminator (ANTAR) domains [Signal transduction mechanisms, Transcription];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 502831305  22 GLTVLLVEDSRFASEAVRLLCLRSG-ARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGspAVIG 100
Cdd:COG3707    3 GLRVLVVDDEPLRRADLREGLREAGyEVVAEAADGEDAVELVRELKPDLVIVDIDMPDRDGLEAARQISEERPA--PVIL 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 502831305 101 LSGDpgmmaeamaaGADAFMEKpldslvAFQARVLSVLPPDVRPAGVRP 149
Cdd:COG3707   81 LTAY----------SDPELIER------ALEAGVSAYLVKPLDPEDLLP 113

two-component system response regulator PmrA;

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 502831305  25 VLLVEDSRFASEAVRLLCLRSGARIRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGPGSPAVI 99
Cdd:PRK10643   3 ILIVEDDTLLLQGLILALQTEGYACDCASTAREAEALLESGHYSLVVLDLGLPDEDGLHLLRRWRQKKYTLPVLI 77

phosphoacceptor receiver (REC) domain of citrate family two-component system response regulators; This family includes Lactobacillus paracasei MaeR, Escherichia coli DcuR and DpiA, Klebsiella pneumoniae CitB, as well as Bacillus DctR, MalR, and CitT. These are all response regulators of two-component systems (TCSs) from the citrate family, and are involved in the transcriptional regulation of genes associated with L-malate catabolism (MaeRK), citrate-specific fermentation (DpiAB, CitAB), plasmid inheritance (DpiAB), anaerobic fumarate respiratory system (DcuRS), and malate transport/utilization (MalKR). REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 502831305  23 LTVLLVEDSRFASEA-VRLLCLRSGAR-IRRADCLRSAHRHLATYRPNVVVVDMGLPDGSGADLIRHIKAAGP 93
Cdd:cd19925    1 INVLIVEDDPMVAEIhRAYVEQVPGFTvIGTAGTGEEALKLLKERQPDLILLDIYLPDGNGLDLLRELRAAGH 73

phosphoacceptor receiver (REC) domain of nitrogen assimilation regulatory protein NtrX and similar proteins; NtrX is part of the two-component regulatory system NtrY/NtrX that is involved in the activation of nitrogen assimilatory genes such as Gln. It is phosphorylated by the histidine kinase NtrY and interacts with sigma-54. NtrX is a member of the NtrC family, characterized by a domain architecture containing an N-terminal REC domain, followed by a central sigma-54 interaction/ATPase domain, and a C-terminal DNA binding domain. NtrC family response regulators are sigma54-dependent transcriptional activators. Also included in this subfamily is Aquifex aeolicus NtrC4. The ability of the central domain to hydrolyze ATP and thus to interact effectively with a complex of RNA polymerase, sigma54, and promoter, is controlled by the phosphorylation status of the REC domain. REC domains function as phosphorylation-mediated switches within response regulators, but some also transfer phosphoryl groups in multistep phosphorelays.

                         10        20        30
                 ....*....|....*....|....*....|....*...
gi 502831305  66 RPNVVVVDMGLPDGSGADLIRHIKAAGPGSPaVIGLSG 103
Cdd:cd17550   42 RPDLVLLDIWLPDMDGLELLKEIKEKYPDLP-VIMISG 78