The Phox Homology domain, a phosphoinositide binding module; The PX domain is a phosphoinositide (PI) binding module involved in targeting proteins to membranes. Proteins containing PX domains interact with PIs and have been implicated in highly diverse functions such as cell signaling, vesicular trafficking, protein sorting, lipid modification, cell polarity and division, activation of T and B cells, and cell survival. Many members of this superfamily bind phosphatidylinositol-3-phosphate (PI3P) but in some cases, other PIs such as PI4P or PI(3,4)P2, among others, are the preferred substrates. In addition to protein-lipid interaction, the PX domain may also be involved in protein-protein interaction, as in the cases of p40phox, p47phox, and some sorting nexins (SNXs). The PX domain is conserved from yeast to humans and is found in more than 100 proteins. The majority of PX domain-containing proteins are SNXs, which play important roles in endosomal sorting.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958658134   3 SPRHPVSAHAVALVQMERlqvdhtapvphpcpdclqrgkrelaklkemsplpflTQTFAFSVCWSDNSDTFARRSWEEFR 82
Cdd:cd06889     1 SPRHPVDVQGVGVMQKRR------------------------------------HKTYMFSVLWSDGSELFVYRSLEEFR 44

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958658134  83 QLQKTLKKIFPVEAGLLQRSERVLPKLPDAPLL-TRRGHTGRGLLRLRLLETYVRSLLATSQHIVTSSTLNSFFAPK 158
Cdd:cd06889    45 KLHKQLKEKFPVEAGLLRSSDRVLPKFKDAPSLgSLKGSTSRSLARLKLLETYCQELLRLDEKVSRSPEVIQFFAPQ 121

Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1958658134 271 QFCATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRYS 310
Cdd:cd12024     1 LYYATRAYEAQKEDELSVPAGVVVEVLQKSDNGWWLIRYN 40

The phosphoinositide binding Phox Homology domain of Nox Organizing protein 1; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. Nox Organizing protein 1 (NoxO1) is a critical regulator of enzyme kinetics of the nonphagocytic NADPH oxidase Nox1, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Nox1 is expressed in colon, stomach, uterus, prostate, and vascular smooth muscle cells. NoxO1, a homolog of the p47phox subunit of phagocytic NADPH oxidase, is involved in targeting activator subunits (such as NoxA1) to Nox1. It is co-localized with Nox1 in the membranes of resting cells and directs the subcellular localization of Nox1. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction. The PX domain of NoxO1 preferentially binds phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2], PI5P, and PI4P.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958658134   3 SPRHPVSAHAVALVQMERlqvdhtapvphpcpdclqrgkrelaklkemsplpflTQTFAFSVCWSDNSDTFARRSWEEFR 82
Cdd:cd06889     1 SPRHPVDVQGVGVMQKRR------------------------------------HKTYMFSVLWSDGSELFVYRSLEEFR 44

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958658134  83 QLQKTLKKIFPVEAGLLQRSERVLPKLPDAPLL-TRRGHTGRGLLRLRLLETYVRSLLATSQHIVTSSTLNSFFAPK 158
Cdd:cd06889    45 KLHKQLKEKFPVEAGLLRSSDRVLPKFKDAPSLgSLKGSTSRSLARLKLLETYCQELLRLDEKVSRSPEVIQFFAPQ 121

Second or C-terminal Src homology 3 domain of NADPH oxidase (Nox) Organizing protein 1; Nox Organizing protein 1 (NoxO1) is a critical regulator of enzyme kinetics of the nonphagocytic NADPH oxidase Nox1, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Nox1 is expressed in colon, stomach, uterus, prostate, and vascular smooth muscle cells. NoxO1 is involved in targeting activator subunits (such as NoxA1) to Nox1. It is co-localized with Nox1 in the membranes of resting cells and directs the subcellular localization of Nox1. NoxO1 contains an N-terminal Phox homology (PX) domain, tandem SH3 domains (N-SH3 and C-SH3), and a C-terminal proline-rich region (PRR). This model characterizes the second SH3 domain (or C-SH3) of NoxO1. The tandem SH3 domains of NoxO1 interact with the PRR of p22phox, which also complexes with Nox1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1958658134 271 QFCATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRYS 310
Cdd:cd12024     1 LYYATRAYEAQKEDELSVPAGVVVEVLQKSDNGWWLIRYN 40

SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

                          10        20        30
                  ....*....|....*....|....*....|...
gi 1958658134 277 AYEGSRPDELSVPSGARVHVLETSDRGWWLCRY 309
Cdd:pfam00018   5 DYTAQEPDELSFKKGDIIIVLEKSEDGWWKGRN 37

SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

                          10        20
                  ....*....|....*....|....*...
gi 1958658134 220 EILDILLRHPSGWWLVENKDQQTAWFPA 247
Cdd:pfam00018  20 DIIIVLEKSEDGWWKGRNKGGKEGLIPS 47

The phosphoinositide binding Phox Homology domain of Nox Organizing protein 1; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. Nox Organizing protein 1 (NoxO1) is a critical regulator of enzyme kinetics of the nonphagocytic NADPH oxidase Nox1, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Nox1 is expressed in colon, stomach, uterus, prostate, and vascular smooth muscle cells. NoxO1, a homolog of the p47phox subunit of phagocytic NADPH oxidase, is involved in targeting activator subunits (such as NoxA1) to Nox1. It is co-localized with Nox1 in the membranes of resting cells and directs the subcellular localization of Nox1. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction. The PX domain of NoxO1 preferentially binds phosphatidylinositol-3,5-bisphosphate [PI(3,5)P2], PI5P, and PI4P.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958658134   3 SPRHPVSAHAVALVQMERlqvdhtapvphpcpdclqrgkrelaklkemsplpflTQTFAFSVCWSDNSDTFARRSWEEFR 82
Cdd:cd06889     1 SPRHPVDVQGVGVMQKRR------------------------------------HKTYMFSVLWSDGSELFVYRSLEEFR 44

                          90       100       110       120       130       140       150
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1958658134  83 QLQKTLKKIFPVEAGLLQRSERVLPKLPDAPLL-TRRGHTGRGLLRLRLLETYVRSLLATSQHIVTSSTLNSFFAPK 158
Cdd:cd06889    45 KLHKQLKEKFPVEAGLLRSSDRVLPKFKDAPSLgSLKGSTSRSLARLKLLETYCQELLRLDEKVSRSPEVIQFFAPQ 121

Second or C-terminal Src homology 3 domain of NADPH oxidase (Nox) Organizing protein 1; Nox Organizing protein 1 (NoxO1) is a critical regulator of enzyme kinetics of the nonphagocytic NADPH oxidase Nox1, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Nox1 is expressed in colon, stomach, uterus, prostate, and vascular smooth muscle cells. NoxO1 is involved in targeting activator subunits (such as NoxA1) to Nox1. It is co-localized with Nox1 in the membranes of resting cells and directs the subcellular localization of Nox1. NoxO1 contains an N-terminal Phox homology (PX) domain, tandem SH3 domains (N-SH3 and C-SH3), and a C-terminal proline-rich region (PRR). This model characterizes the second SH3 domain (or C-SH3) of NoxO1. The tandem SH3 domains of NoxO1 interact with the PRR of p22phox, which also complexes with Nox1. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|
gi 1958658134 271 QFCATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRYS 310
Cdd:cd12024     1 LYYATRAYEAQKEDELSVPAGVVVEVLQKSDNGWWLIRYN 40

Src homology 3 domains of the p47phox subunit of NADPH oxidase and similar domains; This family is composed of the tandem SH3 domains of p47phox subunit of NADPH oxidase and Nox Organizing protein 1 (NoxO1), the four SH3 domains of Tks4 (Tyr kinase substrate with four SH3 domains), the five SH3 domains of Tks5, the SH3 domain of obscurin, Myosin-I, and similar domains. Most members of this group also contain Phox homology (PX) domains, except for obscurin and Myosin-I. p47phox and NoxO1 are regulators of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox) and nonphagocytic NADPH oxidase Nox1, respectively. They play roles in the activation of their respective NADPH oxidase, which catalyzes the transfer of electrons from NADPH to molecular oxygen to form superoxide. Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Obscurin is a giant muscle protein that plays important roles in the organization and assembly of the myofibril and the sarcoplasmic reticulum. Type I myosins (Myosin-I) are actin-dependent motors in endocytic actin structures and actin patches. They play roles in membrane traffic in endocytic and secretory pathways, cell motility, and mechanosensing. Myosin-I contains an N-terminal actin-activated ATPase, a phospholipid-binding TH1 (tail homology 1) domain, and a C-terminal extension which includes an F-actin-binding TH2 domain, an SH3 domain, and an acidic peptide that participates in activating the Arp2/3complex. The SH3 domain of myosin-I is required for myosin-I-induced actin polymerization. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*.
gi 1958658134 197 SMRCLQPFHTLDTKDRPFhtQAKEILDILLRHPSGWWLVENKDQQtAWFPAPYLEE 252
Cdd:cd11856     1 SYVAIADYEAQGDDEISL--QEGEVVEVLEKNDSGWWYVRKGDKE-GWVPASYLEP 53

The phosphoinositide binding Phox Homology domain of Bem1p; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions such as cell signaling, vesicular trafficking, protein sorting, and lipid modification, among others. Members of this subfamily bear similarity to Saccharomyces cerevisiae Bem1p, containing two Src Homology 3 (SH3) domains at the N-terminus, a central PX domain, and a C-terminal PB1 domain. Bem1p is a scaffolding protein that is critical for proper Cdc42p activation during bud formation in yeast. During budding and mating, Bem1p migrates to the plasma membrane where it can serve as an adaptor for Cdc42p and some other proteins. Bem1p also functions as an effector of the G1 cyclin Cln3p and the cyclin-dependent kinase Cdc28p in promoting vacuolar fusion. The PX domain is involved in targeting of proteins to PI-enriched membranes, and may also be involved in protein-protein interaction. The PX domain of Bem1p specifically binds phosphatidylinositol-4-phosphate (PI4P).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1958658134  67 SDNSDTFARRSWEEFRQLQKTLKKIFPVEAGLlQRSERVLPKLP--------DAPLLTRRghtgrgllrlRLLETYVRSL 138
Cdd:cd06890    24 SDGKTRYLCRYYQDFYKLHIALLDLFPAEAGR-NSSKRILPYLPgpvtdvvnDSISLKRL----------NDLNEYLNEL 92

                          90       100
                  ....*....|....*....|
gi 1958658134 139 LATSQHIVTSSTLNSFFAPK 158
Cdd:cd06890    93 INLPAYIQTSEVVRDFFANR 112

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30
                   ....*....|....*....|....*....|....*.
gi 1958658134  274 ATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRY 309
Cdd:smart00326   7 ALYDYTAQDPDELSFKKGDIITVLEKSDDGWWKGRL 42

Src Homology 3 domain superfamily; Src Homology 3 (SH3) domains are protein interaction domains that bind proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. Thus, they are referred to as proline-recognition domains (PRDs). SH3 domains are less selective and show more diverse specificity compared to other PRDs. They have been shown to bind peptide sequences that lack the PxxP motif; examples include the PxxDY motif of Eps8 and the RKxxYxxY sequence in SKAP55. SH3 domain containing proteins play versatile and diverse roles in the cell, including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies, among others. Many members of this superfamily are adaptor proteins that associate with a number of protein partners, facilitating complex formation and signal transduction.

                          10        20        30
                  ....*....|....*....|....*....|....*....
gi 1958658134 271 QFCATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRY 309
Cdd:cd00174     1 YARALYDYEAQDDDELSFKKGDIITVLEKDDDGWWEGEL 39

First Src homology 3 domain of Tyrosine kinase substrate with five SH3 domains; Tks5, also called SH3 and PX domain-containing protein 2A (SH3PXD2A) or Five SH (FISH), is a scaffolding protein and Src substrate that is localized in podosomes, which are electron-dense structures found in Src-transformed fibroblasts, osteoclasts, macrophages, and some invasive cancer cells. It binds and regulates some members of the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. It is required for podosome formation, degradation of the extracellular matrix, and cancer cell invasion. Tks5 contains an N-terminal Phox homology (PX) domain and five SH3 domains. This model characterizes the first SH3 domain of Tks5. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|....*
gi 1958658134 217 QAKEILDILLRHPSGWWLVENKDQQtAWFPAPYLE 251
Cdd:cd12074    19 QAGEVVDVIEKNESGWWFVSTAEEQ-GWVPATYLE 52

Src homology 3 domains; Src homology 3 (SH3) domains bind to target proteins through sequences containing proline and hydrophobic amino acids. Pro-containing polypeptides may bind to SH3 domains in 2 different binding orientations.

                           10        20        30        40        50
                   ....*....|....*....|....*....|....*....|....*....|....*...
gi 1958658134  194 EAQSMRCLQPFHTLDTKDRPFhtQAKEILDILLRHPSGWWLVENKDQQTAWFPAPYLE 251
Cdd:smart00326   1 EGPQVRALYDYTAQDPDELSF--KKGDIITVLEKSDDGWWKGRLGRGKEGLFPSNYVE 56

First Src homology 3 domain of Tyrosine kinase substrate (Tks) proteins; Tks proteins are Src substrates and scaffolding proteins that play important roles in the formation of podosomes and invadopodia, the dynamic actin-rich structures that are related to cell migration and cancer cell invasion. Vertebrates contain two Tks proteins, Tks4 (Tyr kinase substrate with four SH3 domains) and Tks5 (Tyr kinase substrate with five SH3 domains), which display partially overlapping but non-redundant functions. Both associate with the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. Tks5 interacts with N-WASP and Nck, while Tks4 is essential for the localization of MT1-MMP (membrane-type 1 matrix metalloproteinase) to invadopodia. Tks proteins contain an N-terminal Phox homology (PX) domain and four or five SH3 domains. This model characterizes the first SH3 domain of Tks proteins. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|....*
gi 1958658134 217 QAKEILDILLRHPSGWWLVENKDQQtAWFPAPYLE 251
Cdd:cd12015    19 RAGDVVDVIEKNENGWWFVSLEDEQ-GWVPATYLE 52

N-terminal Src Homology 3 domain of Ct10 Regulator of Kinase adaptor proteins; CRK adaptor proteins consists of SH2 and SH3 domains, which bind tyrosine-phosphorylated peptides and proline-rich motifs, respectively. They function downstream of protein tyrosine kinases in many signaling pathways started by various extracellular signals, including growth and differentiation factors. Cellular CRK (c-CRK) contains a single SH2 domain, followed by N-terminal and C-terminal SH3 domains. It is involved in the regulation of many cellular processes including cell growth, motility, adhesion, and apoptosis. CRK has been implicated in the malignancy of various human cancers. The N-terminal SH3 domain of CRK binds a number of target proteins including DOCK180, C3G, SOS, and cABL. The CRK family includes two alternatively spliced protein forms, CRKI and CRKII, that are expressed by the CRK gene, and the CRK-like (CRKL) protein, which is expressed by a distinct gene (CRKL). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1958658134 199 RCLQPFHTLDTKDRPFhtQAKEILDILLRHPSGWWLVENKDQQTAWFPAPYLEE 252
Cdd:cd11758     4 RALFDFPGNDDEDLPF--KKGEILTVIRKPEEQWWNARNSEGKTGMIPVPYVEK 55

Src homology 3 domain of Type I fungal Myosins; Type I myosins (myosin-I) are actin-dependent motors in endocytic actin structures and actin patches. They play roles in membrane traffic in endocytic and secretory pathways, cell motility, and mechanosensing. Saccharomyces cerevisiae has two myosins-I, Myo3 and Myo5, which are involved in endocytosis and the polarization of the actin cytoskeleton. Myosin-I contains an N-terminal actin-activated ATPase, a phospholipid-binding TH1 (tail homology 1) domain, and a C-terminal extension which includes an F-actin-binding TH2 domain, an SH3 domain, and an acidic peptide that participates in activating the Arp2/3complex. The SH3 domain of myosin-I is required for myosin-I-induced actin polymerization. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|....
gi 1958658134 220 EILDILLRHPSGWWLVENKDQQT-AWFPAPYLEE 252
Cdd:cd11858    22 DIVYIVQKEDNGWWLAKKLDESKeGWVPAAYLEE 55

First Src homology 3 domain of Tyrosine kinase substrate with five SH3 domains; Tks5, also called SH3 and PX domain-containing protein 2A (SH3PXD2A) or Five SH (FISH), is a scaffolding protein and Src substrate that is localized in podosomes, which are electron-dense structures found in Src-transformed fibroblasts, osteoclasts, macrophages, and some invasive cancer cells. It binds and regulates some members of the ADAMs family of transmembrane metalloproteases, which function as sheddases and mediators of cell and matrix interactions. It is required for podosome formation, degradation of the extracellular matrix, and cancer cell invasion. Tks5 contains an N-terminal Phox homology (PX) domain and five SH3 domains. This model characterizes the first SH3 domain of Tks5. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|.
gi 1958658134 271 QFCATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRYSE 311
Cdd:cd12074     1 QYVVVSNYEKQENSEISLQAGEVVDVIEKNESGWWFVSTAE 41

Src homology 3 domain of Phospholipase C (PLC) gamma; PLC catalyzes the hydrolysis of phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] to produce Ins(1,4,5)P3 and diacylglycerol (DAG) in response to various receptors. Ins(1,4,5)P3 initiates the calcium signaling cascade while DAG functions as an activator of PKC. PLCgamma catalyzes this reaction in tyrosine kinase-dependent signaling pathways. It is activated and recruited to its substrate at the membrane. Vertebrates contain two forms of PLCgamma, PLCgamma1, which is widely expressed, and PLCgamma2, which is primarily found in haematopoietic cells. PLCgamma contains a Pleckstrin homology (PH) domain followed by an elongation factor (EF) domain, two catalytic regions of PLC domains that flank two tandem SH2 domains, followed by a SH3 domain and C2 domain. The SH3 domain of PLCgamma1 directly interacts with dynamin-1 and can serve as a guanine nucleotide exchange factor (GEF). It also interacts with Cbl, inhibiting its phosphorylation and activity. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|....*.
gi 1958658134 274 ATQAYEGSRPDELSVPSGARVHVLETSDRGWWLCRY 309
Cdd:cd11825     4 ALYDYRAQRPDELSFCKHAIITNVEKEDGGWWRGDY 39

Second Src Homology 3 domain of Nck2 adaptor protein; Nck2 (also called Nckbeta or Growth factor receptor-bound protein 4, Grb4) plays a crucial role in connecting signaling pathways of tyrosine kinase receptors and important effectors in actin dynamics and cytoskeletal remodeling. It binds neuronal signaling proteins such as ephrinB and Disabled-1 (Dab-1) exclusively. Nck adaptor proteins regulate actin cytoskeleton dynamics by linking proline-rich effector molecules to protein tyrosine kinases and phosphorylated signaling intermediates. They contain three SH3 domains and a C-terminal SH2 domain. They function downstream of the PDGFbeta receptor and are involved in Rho GTPase signaling and actin dynamics. Vertebrates contain two Nck adaptor proteins: Nck1 (also called Nckalpha) and Nck2, which show partly overlapping functions but also bind distinct targets. The second SH3 domain of Nck appears to prefer ligands containing the APxxPxR motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity, preferentially a PxxP motif. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|....
gi 1958658134 277 AYEGSRPDELSVPSGARVHVLETSDRGWWLCRYS 310
Cdd:cd11902     8 AYVAEREDELSLVKGSRVTVMEKCSDGWWRGSYN 41

Src homology 3 domain of Myosins Ie, If, and similar proteins; Myosins Ie (MyoIe) and If (MyoIf) are nonmuscle, unconventional, long tailed, class I myosins containing an N-terminal motor domain and a myosin tail with TH1, TH2, and SH3 domains. MyoIe interacts with the endocytic proteins, dynamin and synaptojanin-1, through its SH3 domain; it may play a role in clathrin-dependent endocytosis. In the kidney, MyoIe is critical for podocyte function and normal glomerular filtration. Mutations in MyoIe is associated with focal segmental glomerulosclerosis, a disease characterized by massive proteinuria and progression to end-stage kidney disease. MyoIf is predominantly expressed in the immune system; it plays a role in immune cell motility and innate immunity. Mutations in MyoIf may be associated with the loss of hearing. The MyoIf gene has also been found to be fused to the MLL (Mixed lineage leukemia) gene in infant acute myeloid leukemias (AML). SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1958658134 189 AIHSLEAQsmrclqpfhtlDTKDRPFhtQAKEILDILLRHPSGWWLVENKDQQtAWFPAPYLEE 252
Cdd:cd11827     4 ALYAYDAQ-----------DTDELSF--NEGDIIEILKEDPSGWWTGRLRGKE-GLFPGNYVEK 53

Second Src Homology 3 domain of Nck1 adaptor protein; Nck1 (also called Nckalpha) plays a crucial role in connecting signaling pathways of tyrosine kinase receptors and important effectors in actin dynamics and cytoskeletal remodeling. It binds and activates RasGAP, resulting in the downregulation of Ras. It is also involved in the signaling of endothilin-mediated inhibition of cell migration. Nck adaptor proteins regulate actin cytoskeleton dynamics by linking proline-rich effector molecules to protein tyrosine kinases and phosphorylated signaling intermediates. They contain three SH3 domains and a C-terminal SH2 domain. They function downstream of the PDGFbeta receptor and are involved in Rho GTPase signaling and actin dynamics. Vertebrates contain two Nck adaptor proteins: Nck1 (also called Nckalpha) and Nck2, which show partly overlapping functions but also bind distinct targets. The second SH3 domain of Nck appears to prefer ligands containing the APxxPxR motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity, preferentially a PxxP motif. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

                          10        20        30
                  ....*....|....*....|....*....|...
gi 1958658134 278 YEGSRPDELSVPSGARVHVLETSDRGWWLCRYS 310
Cdd:cd11901    10 YTAEREDELSLVKGTKVIVMEKCSDGWWRGSYN 42

Third Src Homology 3 domain (SH3C) of CD2-associated protein; CD2AP, also called CMS (Cas ligand with Multiple SH3 domains) or METS1 (Mesenchyme-to-Epithelium Transition protein with SH3 domains), is a cytosolic adaptor protein that plays a role in regulating the cytoskeleton. It is critical in cell-to-cell union necessary for kidney function. It also stabilizes the contact between a T cell and antigen-presenting cells. It is primarily expressed in podocytes at the cytoplasmic face of the slit diaphragm and serves as a linker anchoring podocin and nephrin to the actin cytoskeleton. CD2AP contains three SH3 domains, a proline-rich region, and a C-terminal coiled-coil domain. All of these domains enable CD2AP to bind various protein partners and assemble complexes that have been implicated in many different functions. This alignment model represents the third SH3 domain (SH3C) of CD2AP. SH3C has been shown to bind ubiquitin. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1958658134 270 RQFC-ATQAYEGSRPDELSVPSGARVHVL--ETSDRGWW 305
Cdd:cd12056     1 KEYCkALFHYEGTNEDELDFKEGEIILIIskDTGEPGWW 39

The phosphoinositide binding Phox Homology Domain of Class II Phosphoinositide 3-Kinases; The PX domain is a phosphoinositide (PI) binding module present in many proteins with diverse functions. The Phosphoinositide 3-Kinase (PI3K) family of enzymes catalyzes the phosphorylation of the 3-hydroxyl group of the inositol ring of phosphatidylinositol. PI3Ks play an important role in a variety of fundamental cellular processes, including cell motility, the Ras pathway, vesicle trafficking and secretion, immune cell activation and apoptosis. They are also involved in the regulation of clathrin-mediated membrane trafficking as well as ATP-dependent priming of neurosecretory granule exocytosis. PI3Ks are divided into three main classes (I, II, and III) based on their substrate specificity, regulation, and domain structure. Class II PI3Ks preferentially use PI as a substrate to produce PI3P, but can also phosphorylate PI4P to produce PI(3,4)P2. They function as monomers and do not associate with any regulatory subunits. Class II enzymes contain an N-terminal Ras binding domain, a lipid binding C2 domain, a PI3K homology domain of unknown function, an ATP-binding cataytic domain, a PX domain, and a second C2 domain at the C-terminus. Class II PI3Ks include three vertebrate isoforms (alpha, beta, and gamma), the Drosophila PI3K_68D, and similar proteins.

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gi 1958658134  69 NSDTFARRSWEEFRQLQKTLKKIFPVEAgllqrservLPKLPDAPLLTRRGHTGRGLLRLRLLETYVRSLLATSQHIVTS 148
Cdd:cd06883    29 TEPSFVFRTFEEFQELHNKLSLLFPSLK---------LPSFPARVVLGRSHIKQVAERRKIELNSYLKSLFNASPEVAES 99

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gi 1958658134 149 STLNSFFAP 157
Cdd:cd06883   100 DLVYTFFHP 108

SH3 domain; SH3 (Src homology 3) domains are often indicative of a protein involved in signal transduction related to cytoskeletal organization. First described in the Src cytoplasmic tyrosine kinase. The structure is a partly opened beta barrel.

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gi 1958658134 220 EILDILLRHPSGWWLVENKDQQTAWFPA 247
Cdd:pfam00018  20 DIIIVLEKSEDGWWKGRNKGGKEGLIPS 47

The Phox Homology domain, a phosphoinositide binding module; The PX domain is a phosphoinositide (PI) binding module involved in targeting proteins to membranes. Proteins containing PX domains interact with PIs and have been implicated in highly diverse functions such as cell signaling, vesicular trafficking, protein sorting, lipid modification, cell polarity and division, activation of T and B cells, and cell survival. Many members of this superfamily bind phosphatidylinositol-3-phosphate (PI3P) but in some cases, other PIs such as PI4P or PI(3,4)P2, among others, are the preferred substrates. In addition to protein-lipid interaction, the PX domain may also be involved in protein-protein interaction, as in the cases of p40phox, p47phox, and some sorting nexins (SNXs). The PX domain is conserved from yeast to humans and is found in more than 100 proteins. The majority of PX domain-containing proteins are SNXs, which play important roles in endosomal sorting.

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gi 1958658134  60 FAFSVCWSDNSDTFARRSWEEFRQLQKTLKKIFPveagllqrsERVLPKLPDAPLLT---------RRGHTgrgllrlrl 130
Cdd:cd06093    20 YIIEVTTQGGEEWTVYRRYSDFEELHEKLKKKFP---------GVILPPLPPKKLFGnldpefieeRRKQL--------- 81

                          90       100
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gi 1958658134 131 lETYVRSLLAtSQHIVTSSTLNSFF 155
Cdd:cd06093    82 -EQYLQSLLN-HPELRNSEELKEFL 104

First or N-terminal Src homology 3 domain of the p47phox subunit of NADPH oxidase, also called Neutrophil Cytosolic Factor 1; p47phox, or NCF1, is a cytosolic subunit of the phagocytic NADPH oxidase complex (also called Nox2 or gp91phox), which plays a key role in the ability of phagocytes to defend against bacterial infections. NADPH oxidase catalyzes the transfer of electrons from NADPH to oxygen during phagocytosis forming superoxide and reactive oxygen species. p47phox is required for activation of NADH oxidase and plays a role in translocation. It contains an N-terminal Phox homology (PX) domain, tandem SH3 domains (N-SH3 and C-SH3), a polybasic/autoinhibitory region, and a C-terminal proline-rich region (PRR). This model characterizes the first SH3 domain (or N-SH3) of p47phox. In its inactive state, the tandem SH3 domains interact intramolecularly with the autoinhibitory region; upon activation, the tandem SH3 domains are exposed through a conformational change, resulting in their binding to the PRR of p22phox and the activation of NADPH oxidase. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.

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gi 1958658134 217 QAKEILDILLRHPSGWWLVENKDQQtAWFPAPYLE 251
Cdd:cd12021    19 KTGDVVEVVEKSENGWWFCQLKAKR-GWVPASYLE 52