Protein kinase C-related kinase homology region 1 (HR1) Rho-binding domain of vertebrate Cdc42-Interacting Protein 4 and FormiN Binding Protein 1-Like; CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. FNBP1L, also called Toca-1 (Transducer of Cdc42-dependent actin assembly 1), forms a complex with neural WASP; the complex induces the formation of filopodia and endocytic vesicles. FNBP1L is required for Cdc42-induced actin assembly and is essential for autophagy of intracellular pathogens. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. CIP4 and FNBP1L contain an N-terminal F-BAR domain, a central HR1 domain, and a C-terminal SH3 domain. HR1 domains are anti-parallel coiled-coil (ACC) domains that bind small GTPases from the Rho family; the HR1 domain of CIP4 binds Cdc42 and TC10. Translocation of CIP4 is facilitated by its binding to TC10 at the plasma membrane.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463 341 PPEQRRKKLQQRIDELNRELQKESDQKDALNKMKDVYEKNPQMGDPGSLQPKLAETMNNIDRLRMEIHKNEAWLSEVEGK 420
Cdd:cd11628   1 PPEQRRKRLQQKIDELSRELQKEMDQSEALMKMKDVYEKNPQMGDPASLQPQIAETASNIDRLRGELHKYEAWLAEAEGR 80

                .
gi 41581463 421 T 421
Cdd:cd11628  81 V 81

Protein kinase C-related kinase homology region 1 (HR1) Rho-binding domain of vertebrate Cdc42-Interacting Protein 4 and FormiN Binding Protein 1-Like; CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. FNBP1L, also called Toca-1 (Transducer of Cdc42-dependent actin assembly 1), forms a complex with neural WASP; the complex induces the formation of filopodia and endocytic vesicles. FNBP1L is required for Cdc42-induced actin assembly and is essential for autophagy of intracellular pathogens. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. CIP4 and FNBP1L contain an N-terminal F-BAR domain, a central HR1 domain, and a C-terminal SH3 domain. HR1 domains are anti-parallel coiled-coil (ACC) domains that bind small GTPases from the Rho family; the HR1 domain of CIP4 binds Cdc42 and TC10. Translocation of CIP4 is facilitated by its binding to TC10 at the plasma membrane.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463 341 PPEQRRKKLQQRIDELNRELQKESDQKDALNKMKDVYEKNPQMGDPGSLQPKLAETMNNIDRLRMEIHKNEAWLSEVEGK 420
Cdd:cd11628   1 PPEQRRKRLQQKIDELSRELQKEMDQSEALMKMKDVYEKNPQMGDPASLQPQIAETASNIDRLRGELHKYEAWLAEAEGR 80

                .
gi 41581463 421 T 421
Cdd:cd11628  81 V 81

Fes/CIP4, and EFC/F-BAR homology domain; Alignment extended from. Highly alpha-helical. The cytosolic endocytic adaptor proteins in fungi carry this domain at the N-terminus; several of these have been referred to as muniscin proteins. These N-terminal BAR, N-BAR, and EFC/F-BAR domains are found in proteins that regulate membrane trafficking events by inducing membrane tubulation. The domain dimerizes into a curved structure that binds to liposomes and either senses or induces the curvature of the membrane bilayer to cause biophysical changes to the shape of the bilayer; it also thereby recruits other trafficking factors, such as the GTPase dynamin. Most EFC/F-BAR domain-family members localize to actin-rich structures.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 41581463    10 QFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYCpKRSSKDEEPRFTSCVAFFNILNELNDYAGQRE 87
Cdd:pfam00611   1 GFKVLLKRLKQGIKLLEELASFLKERAEIEEEYAKKLQKLAKKFL-KKKKKPEDDGGTLKKAWDELLTETEQLAKQHL 77

Fes/CIP4 homology domain; Alignment extended from original report. Highly alpha-helical. Also known as the RAEYL motif or the S. pombe Cdc15 N-terminal domain.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463      1 MSWGTELWDQFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYcpkRSSKDEEPRFTS-CVAFFNILNEL 79
Cdd:smart00055   1 MGFWSELDDGFEALLSRLKNGLRLLEDLKKFMRERAKIEEEYAKKLQKLSKKL---RAVRDTEPEYGSlSKAWEVLLSET 77

                   ....*...
gi 41581463     80 NDYAGQRE 87
Cdd:smart00055  78 DALAKQHL 85

Uncharacterized conserved protein YgiM, contains N-terminal SH3 domain, DUF1202 family [General function prediction only];

                        10        20        30        40
                ....*....|....*....|....*....|....*....|...
gi 41581463 497 GTLamKEGEVLYIIEEDkgDGWTRARRQNGEEGYVPTSYIDVT 539
Cdd:COG3103  28 GTL--PKGEKVTVLGRS--GGWYKVRYSNGKTGWVSSRYLTVT 66

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Cdc42-Interacting Protein 4 and similar proteins; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. Members of this subfamily typically contain an N-terminal F-BAR domain and a C-terminal SH3 domain. In addition, some members such as FNBP1L contain a central Cdc42-binding HR1 domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463   5 TELWDQFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYCPKRSSKDEEpRFTSCVAFFNILNELNDYAG 84
Cdd:cd07653   1 TELWDQFDNLEKHTQKGIDFLERYGKFVKERAAIEQEYAKKLRKLVKKYLPKKKEEDEY-SFSSVKAFRSILNEVNDIAG 79

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463  85 QREVVAEEMAHRVYGELMRYAHDLKTERKMHLQEGRKAQQYLDMCWKQMDNSKKKFERECREAEKAQQSYERLDNDTNAT 164
Cdd:cd07653  80 QHELIAENLNSNVCKELKTLISELRQERKKHLSEGSKLQQKLESSIKQLEKSKKAYEKAFKEAEKAKQKYEKADADMNLT 159

                       170       180       190       200       210       220       230       240
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463 165 KADVEKAKQQLNLRTHMADENKNEYAAQLQNFNGEQHKHFYVVIPQIYKQLQEMDERRTIKLSECYRGFADSERKVIPII 244
Cdd:cd07653 160 KADVEKAKANANLKTQAAEEAKNEYAAQLQKFNKEQRQHYSTDLPQIFDKLQELDEKRINRTVELLLQAAEIERKVIPII 239

                       250
                ....*....|.
gi 41581463 245 SKCLEGMILAA 255
Cdd:cd07653 240 AKCLDGIKKAG 250

Protein kinase C-related kinase homology region 1 (HR1) Rho-binding domain of vertebrate Cdc42-Interacting Protein 4 and FormiN Binding Protein 1-Like; CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. FNBP1L, also called Toca-1 (Transducer of Cdc42-dependent actin assembly 1), forms a complex with neural WASP; the complex induces the formation of filopodia and endocytic vesicles. FNBP1L is required for Cdc42-induced actin assembly and is essential for autophagy of intracellular pathogens. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. CIP4 and FNBP1L contain an N-terminal F-BAR domain, a central HR1 domain, and a C-terminal SH3 domain. HR1 domains are anti-parallel coiled-coil (ACC) domains that bind small GTPases from the Rho family; the HR1 domain of CIP4 binds Cdc42 and TC10. Translocation of CIP4 is facilitated by its binding to TC10 at the plasma membrane.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463 341 PPEQRRKKLQQRIDELNRELQKESDQKDALNKMKDVYEKNPQMGDPGSLQPKLAETMNNIDRLRMEIHKNEAWLSEVEGK 420
Cdd:cd11628   1 PPEQRRKRLQQKIDELSRELQKEMDQSEALMKMKDVYEKNPQMGDPASLQPQIAETASNIDRLRGELHKYEAWLAEAEGR 80

                .
gi 41581463 421 T 421
Cdd:cd11628  81 V 81

Protein kinase C-related kinase homology region 1 (HR1) Rho-binding domain of Formin Binding Protein 17; FBP17, also called FormiN Binding Protein 1 (FNBP1), is involved in dynamin-mediated endocytosis. It is recruited to clathrin-coated pits late in the endocytosis process and may play a role in the invagination and scission steps. FBP17 binds in vivo to tankyrase, a protein involved in telomere maintenance and mitogen activated protein kinase (MAPK) signaling. It also binds to the Fas ligand and may be implicated in the inflammatory response. FBP17 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain, central HR1 domain, and a C-terminal SH3 domain. HR1 domains are anti-parallel coiled-coil (ACC) domains that bind small GTPases from the Rho family; the HR1 domain of the related protein, CIP4, binds Cdc42 and TC10. Translocation of CIP4 is facilitated by its binding to TC10 at the plasma membrane.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 41581463 342 PEQRRKKLQQRIDELNRELQKESDQKDALNKMKDVYEKNPQMGDPGSLQPKLAETMNNIDRLRMEIHKNEAWLSEVE 418
Cdd:cd11629   1 PEQRRKKLQQKVDELNKDIQKEMDQRDALTKMKDVYIKNPQMGDPASVDHRLEEITQNIEKLRVEVQKFEGWLAEVE 77

Src Homology 3 domain of Cdc42-Interacting Protein 4; This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4), Formin Binding Protein 17 (FBP17), FormiN Binding Protein 1-Like (FNBP1L), and similar proteins. CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. It functions downstream of Cdc42 in PDGF-dependent actin reorganization and cell migration, and also regulates the activity of PDGFRbeta. It uses Src as a substrate in regulating the invasiveness of breast tumor cells. CIP4 may also play a role in the pathogenesis of Huntington's disease. Members of this subfamily typically contain an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain, a central Cdc42-binding HR1 domain, and a C-terminal SH3 domain. The SH3 domain of CIP4 associates with Gapex-5, a Rab31 GEF. 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 41581463 484 HCKAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11911   1 TCTALYDFDGTSEGTLSMEEGEILLVLEEDGGDGWTRVRKNNGDEGYVPTSYIEV 55

Src Homology 3 domain of Cdc42-Interacting Protein 4, Bzz1 and similar domains; This subfamily is composed of Cdc42-Interacting Protein 4 (CIP4) and similar proteins such as Formin Binding Protein 17 (FBP17) and FormiN Binding Protein 1-Like (FNBP1L), as well as yeast Bzz1 (or Bzz1p). CIP4 and FNBP1L are Cdc42 effectors that bind Wiskott-Aldrich syndrome protein (WASP) and function in endocytosis. CIP4 and FBP17 bind to the Fas ligand and may be implicated in the inflammatory response. CIP4 may also play a role in phagocytosis. Bzz1 is also a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Members of this subfamily contain an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain as well as at least one C-terminal SH3 domain. Bzz1 contains a second SH3 domain at the C-terminus. 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 41581463 484 HCKAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11777   1 ECKALYAFVGSSEGTISMTEGEKLSLVEEDKGDGWTRVRRDTGEEGYVPTSYIRI 55

The Extended FES-CIP4 Homology (FCH) or F-BAR (FCH and Bin/Amphiphysin/Rvs) domain, a dimerization module that binds and bends membranes; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. F-BAR domain containing proteins, also known as Pombe Cdc15 homology (PCH) family proteins, include Fes and Fer tyrosine kinases, PACSINs/Syndapins, FCHO, PSTPIP, CIP4-like proteins and srGAPs. Many members also contain an SH3 domain and play roles in endocytosis. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules. These tubules have diameters larger than those observed with N-BARs. The F-BAR domains of some members such as NOSTRIN and Rgd1 are important for the subcellular localization of the protein.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463  10 QFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYCPKRSSKDeeprfTSCVAFFNILNELNDYAGQ-REV 88
Cdd:cd07610   1 GFELLEKRTELGLDLLKDLREFLKKRAAIEEEYAKNLQKLAKKFSKKPESGK-----TSLGTSWNSLREETESAATvHEE 75

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463  89 VAEEMAHRVYGELMRYAHDLKTERKMHLQEGRKAQQYLDMCWKqmdNSKKKFERECREAEKAQQSY--ERLDNDTNATKA 166
Cdd:cd07610  76 LSEKLSQLIREPLEKVKEDKEQARKKELAEGEKLKKKLQELWA---KLAKKADEEYREQVEKLNPAqsEYEEEKLNKIQA 152

                       170       180       190       200
                ....*....|....*....|....*....|....*....|....*
gi 41581463 167 DvekaKQQLNLRTHMADENKNEYAaqlqNFNGEQHKHFYVVIPQI 211
Cdd:cd07610 153 E----QEREEERLEILKDNLKNYI----NAIKEIPQKIQQELEQS 189

First Src Homology 3 domain of Bzz1 and similar domains; Bzz1 (or Bzz1p) is a WASP/Las17-interacting protein involved in endocytosis and trafficking to the vacuole. It physically interacts with type I myosins and functions in the early steps of endocytosis. Together with other proteins, it induces membrane scission in yeast. Bzz1 contains an N-terminal F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs), a central coiled-coil, and two C-terminal SH3 domains. This model represents the first C-terminal SH3 domain. 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 41581463 486 KAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11912   3 KVLYDYTASGDDEVSISEGEEVTVLEPDDGSGWTKVRNGSGEEGLVPTSYIEI 55

Src Homology 3 domain of Sorting Nexin 9 and similar proteins; Sorting nexins (SNXs) are Phox homology (PX) domain containing proteins that are involved in regulating membrane traffic and protein sorting in the endosomal system. SNXs differ from each other in their lipid-binding specificity, subcellular localization and specific function in the endocytic pathway. This subfamily consists of SH3 domain containing SNXs including SNX9, SNX18, SNX33, and similar proteins. SNX9 is localized to plasma membrane endocytic sites and acts primarily in clathrin-mediated endocytosis, while SNX18 is localized to peripheral endosomal structures, and acts in a trafficking pathway that is clathrin-independent but relies on AP-1 and PACS1. 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 41581463 485 CKAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11763   2 VRALYDFDSQPSGELSLRAGEVLTITRQDVGDGWLEGRNSRGEVGLFPSSYVEI 55

Fes/CIP4 homology domain; Alignment extended from original report. Highly alpha-helical. Also known as the RAEYL motif or the S. pombe Cdc15 N-terminal domain.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463      1 MSWGTELWDQFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYcpkRSSKDEEPRFTS-CVAFFNILNEL 79
Cdd:smart00055   1 MGFWSELDDGFEALLSRLKNGLRLLEDLKKFMRERAKIEEEYAKKLQKLSKKL---RAVRDTEPEYGSlSKAWEVLLSET 77

                   ....*...
gi 41581463     80 NDYAGQRE 87
Cdd:smart00055  78 DALAKQHL 85

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        40
                  ....*....|....*....|....*....|....*....|....*...
gi 41581463   486 KAIYPFDGHNEGTLAMKEGEVLYIIeEDKGDGWTRARRQNGEEGYVPT 533
Cdd:pfam00018   1 VALYDYTAQEPDELSFKKGDIIIVL-EKSEDGWWKGRNKGGKEGLIPS 47

Third Src Homology 3 domain of Nck adaptor proteins; This group contains the third SH3 domain of Nck, the first SH3 domain of Caenorhabditis elegans Ced-2 (Cell death abnormality protein 2), and similar domains. 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 (also called Nckbeta or Growth factor receptor-bound protein 4, Grb4), which show partly overlapping functions but also bind distinct targets. Their SH3 domains are involved in recruiting downstream effector molecules, such as the N-WASP/Arp2/3 complex, which when activated induces actin polymerization that results in the production of pedestals, or protrusions of the plasma membrane. The third SH3 domain of Nck appears to prefer ligands with a PxAPxR motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity, preferentially a PxxP motif. Ced-2 is a cell corpse engulfment protein that interacts with Ced-5 in a pathway that regulates the activation of Ced-10, a Rac small GTPase.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKGD-GWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11767   4 ALYPFTGENDEELSFEKGERLEIIEKPEDDpDWWKARNALGTTGLVPRNYVEV 56

Src Homology 3 domain of Nephrocystin (or Nephrocystin-1); Nephrocystin contains an SH3 domain involved in signaling pathways that regulate cell adhesion and cytoskeletal organization. It is a protein that in humans is associated with juvenile nephronophthisis, an inherited kidney disease characterized by renal fibrosis that lead to chronic renal failure in children. It is localized in cell-cell junctions in renal duct cells, and is known to interact with Ack1, an activated Cdc42-associated kinase. 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 41581463 485 CKAIYPFDGHNEGTLAMKEGEVLYIIEEdKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11770   2 YEALSDFQAEQEGDLSFKKGEVLRIISK-RADGWWLAENSKGNRGLVPKTYLKV 54

Third Src Homology 3 domain of the fungal endocytic adaptor protein Sla1p; Sla1p facilitates endocytosis by playing a role as an adaptor protein in coupling components of the actin cytoskeleton to the endocytic machinery. It interacts with Abp1p, Las17p and Pan1p, which are activator proteins of actin-related protein 2/3 (Arp2/3). Sla1p contains multiple domains including three SH3 domains, a SAM (sterile alpha motif) domain, and a Sla1 homology domain 1 (SHD1), which binds to the NPFXD motif that is found in many integral membrane proteins such as the Golgi-localized Arf-binding protein Lsb5p and the P4-ATPases, Drs2p and Dnf1p. The third SH3 domain of Sla1p can bind ubiquitin while retaining the ability to bind proline-rich ligands; monoubiquitination of target proteins signals internalization and sorting through the endocytic pathway. 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 41581463 486 KAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQ-NGEEGYVPTSYIDV 538
Cdd:cd11775   4 KVLYDFDAQSDDELTVKEGDVVYILDDKKSKDWWMVENVsTGKEGVVPASYIEI 57

Src Homology 3 domain of Tec-like Protein Tyrosine Kinases; The Tec (Tyrosine kinase expressed in hepatocellular carcinoma) subfamily is composed of Tec, Btk, Bmx (Etk), Itk (Tsk, Emt), Rlk (Txk), and similar proteins. They are cytoplasmic (or nonreceptor) tyr kinases containing Src homology protein interaction domains (SH3, SH2) N-terminal to the catalytic tyr kinase domain. Most Tec subfamily members (except Rlk) also contain an N-terminal pleckstrin homology (PH) domain, which binds the products of PI3K and allows membrane recruitment and activation. In addition, some members contain the Tec homology (TH) domain, which contains proline-rich and zinc-binding regions. Tec kinases are expressed mainly by haematopoietic cells, although Tec and Bmx are also found in endothelial cells. B-cells express Btk and Tec, while T-cells express Itk, Txk, and Tec. Collectively, Tec kinases are expressed in a variety of myeloid cells such as mast cells, platelets, macrophages, and dendritic cells. Each Tec kinase shows a distinct cell-type pattern of expression. The function of Tec kinases in lymphoid cells have been studied extensively. They play important roles in the development, differentiation, maturation, regulation, survival, and function of B-cells and T-cells. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEeDKGDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd11768   4 ALYDFQPIEPGDLPLEKGEEYVVLD-DSNEHWWRARDKNGNEGYIPSNYV 52

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Schizosaccharomyces pombe Cdc15, and similar proteins; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. This subfamily is composed of Schizosaccharomyces pombe Cdc15 and Imp2, and similar proteins. These proteins contain an N-terminal F-BAR domain and a C-terminal SH3 domain. S. pombe Cdc15 and Imp2 play both distinct and overlapping roles in the maintenance and strengthening of the contractile ring at the division site, which is required in cell division. Cdc15 is a component of the actomyosin ring and is required in normal cytokinesis. Imp2 colocalizes with the medial ring during septation and is required for normal septation. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463  31 FVKERIEIEQNYAKQLRNLVKKYcpkrSSKDEEprfTSCVAFFNIL-NELNDYAGQREVVAEEMAHRVYGELMRYAHDLK 109
Cdd:cd07651  27 FYKERASIEEEYAKRLEKLSRKS----LGGSEE---GGLKNSLDTLrLETESMAKSHLKFAKQIRQDLEEKLAAFASSYT 99

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463 110 TERKM---HLQEGRKAQQyldMCWKQMDNSKKKFEREC---------------REAEKAQQSYERLDNDTNATKADVEKA 171
Cdd:cd07651 100 QKRKKiqsHMEKLLKKKQ---DQEKYLEKAREKYEADCskinsytlqsqltwgKELEKNNAKLNKAQSSINSSRRDYQNA 176

                       170       180
                ....*....|....*....|....*
gi 41581463 172 KQQLnLRTHmaDENKNEYAAQLQNF 196
Cdd:cd07651 177 VKAL-RELN--EIWNREWKAALDDF 198

Src homology 3 domain of Src kinase-like Protein Tyrosine Kinases; Src subfamily members include Src, Lck, Hck, Blk, Lyn, Fgr, Fyn, Yrk, Yes, and Brk. Src (or c-Src) proteins are cytoplasmic (or non-receptor) PTKs which are anchored to the plasma membrane. They contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). However, Brk lacks the N-terminal myristoylation sites. Src proteins are involved in signaling pathways that regulate cytokine and growth factor responses, cytoskeleton dynamics, cell proliferation, survival, and differentiation. They were identified as the first proto-oncogene products, and they regulate cell adhesion, invasion, and motility in cancer cells, and tumor vasculature, contributing to cancer progression and metastasis. Src kinases are overexpressed in a variety of human cancers, making them attractive targets for therapy. They are also implicated in acute inflammatory responses and osteoclast function. Src, Fyn, Yes, and Yrk are widely expressed, while Blk, Lck, Hck, Fgr, Lyn, and Brk show a limited expression pattern. This subfamily also includes Drosophila Src42A, Src oncogene at 42A (also known as Dsrc41) which accumulates at sites of cell-cell or cell-matrix adhesion, and participates in Drosphila development and wound healing. It has been shown to promote tube elongation in the tracheal system, is essential for proper cell-cell matching during dorsal closure, and regulates cell-cell contacts in developing Drosophila eyes. The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKGDgWTRARRQN-GEEGYVPTSY 535
Cdd:cd11845   4 ALYDYEARTDDDLSFKKGDRLQILDDSDGD-WWLARHLStGKEGYIPSNY 52

Src homology 3 domain of SH3 protein interacting with Nck, 90 kDa (SPIN90); SPIN90 is also called NCK interacting protein with SH3 domain (NCKIPSD), Dia-interacting protein (DIP), 54 kDa vimentin-interacting protein (VIP54), or WASP-interacting SH3-domain protein (WISH). It is an F-actin binding protein that regulates actin polymerization and endocytosis. It associates with the Arp2/3 complex near actin filaments and determines filament localization at the leading edge of lamellipodia. SPIN90 is expressed in the early stages of neuronal differentiation and plays a role in regulating growth cone dynamics and neurite outgrowth. It also interacts with IRSp53 and regulates cell motility by playing a role in the formation of membrane protrusions. SPIN90 contains an N-terminal SH3 domain, a proline-rich domain, and a C-terminal VCA (verprolin-homology and cofilin-like acidic) domain. 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 41581463 486 KAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDgWTRARRQNGEEGYVPTSYI 536
Cdd:cd11849   3 RALYDFKSAEPNTLSFSEGETFLLLERSNAH-WWLVTNHSGETGYVPANYV 52

Src Homology 3 domain of fungal peroxisomal membrane protein Pex13p; Pex13p, located in the peroxisomal membrane, contains two transmembrane regions and a C-terminal SH3 domain. It binds to the peroxisomal targeting type I (PTS1) receptor Pex5p and the docking factor Pex14p through its SH3 domain. It is essential for both PTS1 and PTS2 protein import pathways into the peroxisomal matrix. Pex13p binds Pex14p, which contains a PxxP motif, in a classical fashion to the proline-rich ligand binding site of its SH3 domain. It binds the WxxxF/Y motif of Pex5p in a novel site that does not compete with Pex14p binding. 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 41581463 485 CKAIYPFDGHN-EGTLAMKEGEVLYIIE----EDKGDGWTRARRQNGEEGYVPTSYIDV 538
Cdd:cd11771   2 CRALYDFTPENpEMELSLKKGDIVAVLSktdpLGRDSEWWKGRTRDGRIGWFPSNYVEV 60

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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKGdGWTRARRqNGEEGYVPTSYID 537
Cdd:cd11856   4 AIADYEAQGDDEISLQEGEVVEVLEKNDS-GWWYVRK-GDKEGWVPASYLE 52

Src Homology 3 domain of metazoan osteoclast stimulating factor 1; OSTF1, also named OSF or SH3P2, is a signaling protein containing SH3 and ankyrin-repeat domains. It acts through a Src-related pathway to enhance the formation of osteoclasts and bone resorption. It also acts as a negative regulator of cell motility. 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 41581463 486 KAIYPFDGHNEGTLAMKEGEVLYIIEEDKgDGWTRArRQNGEEGYVPTSYI 536
Cdd:cd11772   3 RALYDYEAQHPDELSFEEGDLLYISDKSD-PNWWKA-TCGGKTGLIPSNYV 51

First Src Homology 3 domain of the fungal endocytic adaptor protein Sla1p; Sla1p facilitates endocytosis by playing a role as an adaptor protein in coupling components of the actin cytoskeleton to the endocytic machinery. It interacts with Abp1p, Las17p and Pan1p, which are activator proteins of actin-related protein 2/3 (Arp2/3). Sla1p contains multiple domains including three SH3 domains, a SAM (sterile alpha motif) domain, and a Sla1 homology domain 1 (SHD1), which binds to the NPFXD motif that is found in many integral membrane proteins such as the Golgi-localized Arf-binding protein Lsb5p and the P4-ATPases, Drs2p and Dnf1p. 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 41581463 485 CKAIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQN-----GEEGYVPTSY 535
Cdd:cd11773   2 YKALYDYEPQTEDELTIQEDDILYLLEKSDDDWWKVKLKVNssdddEPVGLVPATY 57

Src homology 3 domain of Lyn Protein Tyrosine Kinase; Lyn is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. Lyn is expressed in B lymphocytes and myeloid cells. It exhibits both positive and negative regulatory roles in B cell receptor (BCR) signaling. Lyn, as well as Fyn and Blk, promotes B cell activation by phosphorylating ITAMs (immunoreceptor tyr activation motifs) in CD19 and in Ig components of BCR. It negatively regulates signaling by its unique ability to phosphorylate ITIMs (immunoreceptor tyr inhibition motifs) in cell surface receptors like CD22 and CD5. Lyn also plays an important role in G-CSF receptor signaling by phosphorylating a variety of adaptor molecules. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEdKGDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd12004   4 ALYPYDGIHEDDLSFKKGEKLKVIEE-HGEWWKARSLTTKKEGFIPSNYV 52

Src Homology 3 domain of Bruton's tyrosine kinase; BTK is a cytoplasmic (or nonreceptor) tyr kinase containing Src homology protein interaction domains (SH3, SH2) N-terminal to the catalytic tyr kinase domain. It also contains an N-terminal pleckstrin homology (PH) domain, which binds the products of PI3K and allows membrane recruitment and activation, and the Tec homology (TH) domain with proline-rich and zinc-binding regions. Btk is expressed in B-cells, and a variety of myeloid cells including mast cells, platelets, neutrophils, and dendrictic cells. It interacts with a variety of partners, from cytosolic proteins to nuclear transcription factors, suggesting a diversity of functions. Stimulation of a diverse array of cell surface receptors, including antigen engagement of the B-cell receptor (BCR), leads to PH-mediated membrane translocation of Btk and subsequent phosphorylation by Src kinase and activation. Btk plays an important role in the life cycle of B-cells including their development, differentiation, proliferation, survival, and apoptosis. Mutations in Btk cause the primary immunodeficiency disease, X-linked agammaglobulinaemia (XLA) in humans. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVlYIIEEDKGDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd11906   5 ALYDYTPMNAQDLQLRKGEE-YVILEESNLPWWRARDKNGREGYIPSNYV 53

Src homology 3 domain of Nitric Oxide Synthase TRaffic INducer; Nostrin is expressed in endothelial and epithelial cells and is involved in the regulation, trafficking and targeting of endothelial NOS (eNOS). It facilitates the endocytosis of eNOS by coordinating the functions of dynamin and the Wiskott-Aldrich syndrome protein (WASP). Increased expression of Nostrin may be correlated to preeclampsia. Nostrin contains an N-terminal F-BAR domain and a C-terminal SH3 domain. 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 41581463 485 CKAIYPFDGHNEGTLAMKEGEVLYIIEEDKgDGWTRArRQNGEEGYVPTSYIDV 538
Cdd:cd11823   2 CKALYSYTANREDELSLQPGDIIEVHEKQD-DGWWLG-ELNGKKGIFPATYVEE 53

Src homology 3 domain of Blk Protein Tyrosine Kinase; Blk is a member of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. It is expressed specifically in B-cells and is involved in pre-BCR (B-cell receptor) signaling. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDkGDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd12009   4 AQYDFVPSNERDLQLKKGEKLQVLKSD-GEWWLAKSLTTGKEGYIPSNYV 52

Src Homology 3 domain of Epidermal growth factor receptor kinase substrate 8 and similar proteins; This group is composed of Eps8 and Eps8-like proteins including Eps8-like 1-3, among others. These proteins contain N-terminal Phosphotyrosine-binding (PTB), central SH3, and C-terminal effector domains. Eps8 binds either Abi1 (also called E3b1) or Rab5 GTPase activating protein RN-tre through its SH3 domain. With Abi1 and Sos1, it becomes part of a trimeric complex that is required to activate Rac. Together with RN-tre, it inhibits the internalization of EGFR. The SH3 domains of Eps8 and similar proteins recognize peptides containing a PxxDY motif, instead of the classical PxxP motif. SH3 domains are protein interaction domains that usually bind to proline-rich ligands with moderate affinity and selectivity. 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 41581463 486 KAIYPFDGHNEGTLAMKEGEVLYIIeeDKGDGWTRARRQNGEEGYVP 532
Cdd:cd11764   3 RVLYDFTARNSKELSVLKGEYLEVL--DDSRQWWKVRNSRGQVGYVP 47

Second C-terminal Src homology 3 domain of Dynamin Binding Protein, also called Tuba, and similar domains; DNMBP or Tuba is a cdc42-specific guanine nucleotide exchange factor (GEF) that contains four N-terminal SH3 domains, a central RhoGEF [or Dbl homology (DH)] domain followed by a Bin/Amphiphysin/Rvs (BAR) domain, and two C-terminal SH3 domains. It provides a functional link between dynamin, Rho GTPase signaling, and actin dynamics. It plays an important role in regulating cell junction configuration. The C-terminal SH3 domains of DNMBP bind to N-WASP and Ena/VASP proteins, which are key regulatory proteins of the actin cytoskeleton. Also included in this subfamily is the second C-terminal SH3 domain of Rho guanine nucleotide exchange factor 37 (ARHGEF37), whose function is still unknown. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIE--EDKG-DGWTRArRQNGEEGYVPTSYID 537
Cdd:cd11800   4 ALYTFEARSPGELSVTEGQVVTVLEkhDLKGnPEWWLV-EDRGKQGYVPSNYLA 56

Src homology 3 domain of Fyn and Yrk Protein Tyrosine Kinases; Fyn and Yrk (Yes-related kinase) are members of the Src subfamily of proteins, which are cytoplasmic (or non-receptor) PTKs. Fyn, together with Lck, plays a critical role in T-cell signal transduction by phosphorylating ITAM (immunoreceptor tyr activation motif) sequences on T-cell receptors, ultimately leading to the proliferation and differentiation of T-cells. In addition, Fyn is involved in the myelination of neurons, and is implicated in Alzheimer's and Parkinson's diseases. Yrk has been detected only in chickens. It is primarily found in neuronal and epithelial cells and in macrophages. It may play a role in inflammation and in response to injury. Src kinases contain an N-terminal SH4 domain with a myristoylation site, followed by SH3 and SH2 domains, a tyr kinase domain, and a regulatory C-terminal region containing a conserved tyr. They are activated by autophosphorylation at the tyr kinase domain, but are negatively regulated by phosphorylation at the C-terminal tyr by Csk (C-terminal Src Kinase). The SH3 domain of Src kinases contributes to substrate recruitment by binding adaptor proteins/substrates, and regulation of kinase activity through an intramolecular interaction. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd12006   5 ALYDYEARTEDDLSFHKGEKFQILNSSEGDWWEARSLTTGETGYIPSNYV 54

Src Homology 3 domain of Interleukin-2-inducible T-cell Kinase; ITK (also known as Tsk or Emt) is a cytoplasmic (or nonreceptor) tyr kinase containing Src homology protein interaction domains (SH3, SH2) N-terminal to the catalytic tyr kinase domain. It also contains an N-terminal pleckstrin homology (PH) domain, which binds the products of PI3K and allows membrane recruitment and activation, and the Tec homology (TH) domain, which contains proline-rich and zinc-binding regions. ITK is expressed in T-cells and mast cells, and is important in their development and differentiation. Of the three Tec kinases expressed in T-cells, ITK plays the predominant role in T-cell receptor (TCR) signaling. It is activated by phosphorylation upon TCR crosslinking and is involved in the pathway resulting in phospholipase C-gamma1 activation and actin polymerization. It also plays a role in the downstream signaling of the T-cell costimulatory receptor CD28, the T-cell surface receptor CD2, and the chemokine receptor CXCR4. In addition, ITK is crucial for the development of T-helper(Th)2 effector responses. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKgDGWTRARRQNGEEGYVPTSYI 536
Cdd:cd11908   5 ALYDYQTNDPQELALRYNEEYHLLDSSE-IHWWRVQDKNGHEGYVPSSYL 53

The F-BAR (FES-CIP4 Homology and Bin/Amphiphysin/Rvs) domain of Slit-Robo GTPase Activating Proteins; F-BAR domains are dimerization modules that bind and bend membranes and are found in proteins involved in membrane dynamics and actin reorganization. Slit-Robo GTPase Activating Proteins (srGAPs) are Rho GAPs that interact with Robo1, the transmembrane receptor of Slit proteins. Slit proteins are secreted proteins that control axon guidance and the migration of neurons and leukocytes. Vertebrates contain three isoforms of srGAPs, all of which are expressed during embryonic and early development in the nervous system but with different localization and timing. srGAPs contain an N-terminal F-BAR domain, a Rho GAP domain, and a C-terminal SH3 domain. F-BAR domains form banana-shaped dimers with a positively-charged concave surface that binds to negatively-charged lipid membranes. They can induce membrane deformation in the form of long tubules.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463   5 TELWDQFDSLDKHTQWGIDFLERYAKFVKERIEIEQNYAKQLRNLVKKYCPK----RSSKDEEPRFTSCVAFFNILNE-- 78
Cdd:cd07656   1 QQLSEQLKCLDLRTEAQVQLLADLQDYFRRRAEIELEYSRSLEKLADRFSSKhkneKSKREDWSLLSPVNCWNTLLVQtk 80

                        90       100       110       120       130       140       150       160
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 41581463  79 --------LND-YAG---QREVVAEEMAHRVY-----------GELMRYAHDLKTERK---MHLQEGRKAQQYLdmcwKQ 132
Cdd:cd07656  81 qesrdhstLSDiYSNnlvQRLGQMSEDLQRISkkcreigsqlhDELLRVLNELQTAMKtyhTYHAESKSAERKL----KE 156

                       170       180       190       200       210       220       230
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 41581463 133 MDNSKKKFERECREAEKAQQSYERLDNDTNATKADVEKAKQQlnlrthmADENKNEYAAQLQNFNGEQHKHF 204
Cdd:cd07656 157 AEKQEEKQEQSPEKKLERSRSSKKIEKEVEKRQAKYSEAKLK-------CTKARNEYLLNLAAANATIHKYF 221

N-terminal Src homology 3 domain of Growth factor receptor-bound protein 2; GRB2 is a critical signaling molecule that regulates the Ras pathway by linking tyrosine kinases to the Ras guanine nucleotide releasing protein Sos (son of sevenless), which converts Ras to the active GTP-bound state. It is ubiquitously expressed in all tissues throughout development and is important in cell cycle progression, motility, morphogenesis, and angiogenesis. In lymphocytes, GRB2 is associated with antigen receptor signaling components. GRB2 contains an N-terminal SH3 domain, a central SH2 domain, and a C-terminal SH3 domain. Its N-terminal SH3 domain binds to Sos and Sos-derived proline-rich peptides. 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 41581463 487 AIYPFDGHNEGTLAMKEGEVLYIIEEDKGDGWTRArRQNGEEGYVPTSYIDV 538
Cdd:cd11946   5 AKYDFKATADDELSFKRGDILKVLNEECDQNWYKA-ELNGKDGFIPKNYIEM 55