Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 241 KPVITMEPLGLTeegfwASEREEVTLSCLAASNPPSHYVWLRDHTQVHTGP-----------TYVIARAGRVHTGLYTCL 309
Cdd:pfam13927   1 KPVITVSPSSVT-----VREGETVTLTCEATGSPPPTITWYKNGEPISSGStrsrslsgsnsTLTISNVTRSDAGTYTCV 75

                  ...
gi 1434110709 310 ARN 312
Cdd:pfam13927  76 ASN 78

Fibronectin type III domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 598 PAPPNVTISRLTygrhRREVQLQWAIL--GPGNLTGFLVQRKaSALGPGAGAWETaasdIEPESRGRRLGGLDPGVLYAF 675
Cdd:pfam00041   1 SAPSNLTVTDVT----STSLTVSWTPPpdGNGPITGYEVEYR-PKNSGEPWNEIT----VPGTTTSVTLTGLKPGTEYEV 71

                          90
                  ....*....|....
gi 1434110709 676 RILALNHHTAGHPS 689
Cdd:pfam00041  72 RVQAVNGGGEGPPS 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 241 KPVITMEPLGLTeegfwASEREEVTLSCLAASNPPSHYVWLRDHTQVHTGP-----------TYVIARAGRVHTGLYTCL 309
Cdd:pfam13927   1 KPVITVSPSSVT-----VREGETVTLTCEATGSPPPTITWYKNGEPISSGStrsrslsgsnsTLTISNVTRSDAGTYTCV 75

                  ...
gi 1434110709 310 ARN 312
Cdd:pfam13927  76 ASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709  257 WASEREEVTLSCLAASNPPSHYVWLRDHTQVHTGP------------TYVIARAGRVHTGLYTCLARNSYLDTRTQTTVQ 324
Cdd:smart00410   5 TVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESgrfsvsrsgstsTLTISNVTPEDSGTYTCAATNSSGSASSGTTLT 84

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 501 PQLDVAEPRVSVLEGGEAWLECSLRGGtPPAQLLWLGPQQQKVDPGTSGFMLHPEGAQLRlgIYDADPaHHRGTYQCVAR 580
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGS-PPPTITWYKNGEPISSGSTRSRSLSGSNSTLT--ISNVTR-SDAGTYTCVAS 77

                  .
gi 1434110709 581 N 581
Cdd:pfam13927  78 N 78

Fibronectin type III domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 598 PAPPNVTISRLTygrhRREVQLQWAIL--GPGNLTGFLVQRKaSALGPGAGAWETaasdIEPESRGRRLGGLDPGVLYAF 675
Cdd:pfam00041   1 SAPSNLTVTDVT----STSLTVSWTPPpdGNGPITGYEVEYR-PKNSGEPWNEIT----VPGTTTSVTLTGLKPGTEYEV 71

                          90
                  ....*....|....
gi 1434110709 676 RILALNHHTAGHPS 689
Cdd:pfam00041  72 RVQAVNGGGEGPPS 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1434110709 149 KPQVRLSNPSPV--EGASVVATCAVREGTEPvTFAWQH----RAPRGLGEALVGVTEPLFQLDPVNRTHLGWYMCSASN 221
Cdd:pfam13927   1 KPVITVSPSSVTvrEGETVTLTCEATGSPPP-TITWYKngepISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709  598 PAPPNVTISRLTygrhRREVQLQWAILGPGNLTGFLVQRKASaLGPGAGAWETAASDiePESRGRRLGGLDPGVLYAFRI 677
Cdd:smart00060   2 SPPSNLRVTDVT----STSVTLSWEPPPDDGITGYIVGYRVE-YREEGSEWKEVNVT--PSSTSYTLTGLKPGTEYEFRV 74

                   ....*....
gi 1434110709  678 LALNHHTAG 686
Cdd:smart00060  75 RAVNGAGEG 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 241 KPVITMEPLGLTeegfwASEREEVTLSCLAASNPPSHYVWLRDHTQVHTGP-----------TYVIARAGRVHTGLYTCL 309
Cdd:pfam13927   1 KPVITVSPSSVT-----VREGETVTLTCEATGSPPPTITWYKNGEPISSGStrsrslsgsnsTLTISNVTRSDAGTYTCV 75

                  ...
gi 1434110709 310 ARN 312
Cdd:pfam13927  76 ASN 78

Immunoglobulin like; IG domains that cannot be classified into one of IGv1, IGc1, IGc2, IG.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709  257 WASEREEVTLSCLAASNPPSHYVWLRDHTQVHTGP------------TYVIARAGRVHTGLYTCLARNSYLDTRTQTTVQ 324
Cdd:smart00410   5 TVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESgrfsvsrsgstsTLTISNVTPEDSGTYTCAATNSSGSASSGTTLT 84

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 264 VTLSCLAASNPPSHYVWLRDHTQVHTGPTY-----------VIARAGRVHTGLYTCLARNSYLDTRTQTT 322
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLPPSSRDsrrselgngtlTISNVTLEDSGTYTCVASNSAGGSASASV 70

Fourth Ig-like domain from smooth muscle myosin light chain kinase and similar domains ; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain from smooth muscle myosin light chain kinase (MYLK) and similar domains. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of this group shows that the fourth Ig-like domain from myosin light chain kinase lacks this strand and thus belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 500 APQLDVAEPRVSVLEGGEAWLECSLRGgTPPAQLLWLGPQQQkVDPGTSGFMLHPEGAQLRlgIYDADPAHHrGTYQCVA 579
Cdd:cd20976     1 APSFSSVPKDLEAVEGQDFVAQCSARG-KPVPRITWIRNAQP-LQYAADRSTCEAGVGELH--IQDVLPEDH-GTYTCLA 75

                          90
                  ....*....|....*
gi 1434110709 580 RNAVGNSSQSVLLEV 594
Cdd:cd20976    76 KNAAGQVSCSAWVTV 90

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 598 PAPPNVTISRLTygrhRREVQLQW--AILGPGNLTGFLVQRKASalgpGAGAWETAASDIEPESRGRrLGGLDPGVLYAF 675
Cdd:cd00063     2 SPPTNLRVTDVT----STSVTLSWtpPEDDGGPITGYVVEYREK----GSGDWKEVEVTPGSETSYT-LTGLKPGTEYEF 72

                          90
                  ....*....|....*
gi 1434110709 676 RILALNHHTAGHPSE 690
Cdd:cd00063    73 RVRAVNGGGESPPSE 87

Fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains; member of the C2-set IgSF domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of the carcinoembryonic antigen (CEA) related cell adhesion molecule 5 (CEACAM5) and similar domains. The CEA family is a group of anchored or secreted glycoproteins, expressed by epithelial cells, leukocytes, endothelial cells and placenta. The CEA family is divided into the CEACAM and pregnancy-specific glycoprotein (PSG) subfamilies. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5), also known as CD66e (Cluster of Differentiation 66e), is a cell surface glycoprotein that plays a role in cell adhesion, intracellular signaling and tumor progression. Diseases associated with CEACAM5 include lung cancer and rectum cancer. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. This group belongs to the C2-set of IgSF domains, having A, B, and E strands in one beta-sheet and A', G, F, C' in the other. Unlike other Ig domain sets, the C2-set lacks the D strand.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1434110709 262 EEVTLSCLAASNPPSHYVWLRDHTQVHTGPTYVIARAGRVHTGLYTCLARNSY--LDTRTQTTVQL 325
Cdd:cd20948    11 ENLNLSCHAASNPPAQYSWTINGTFQTSSQELFLPAITENNEGTYTCSAHNSLtgKNISLVLSVTV 76

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 505 VAEPRVSVLEGGEAWLECSLRGGTPPAQLLWLGPQQQKVDP--------GTSGFMLHPEGAQLRlgiyDAdpahhrGTYQ 576
Cdd:pfam00047   1 SAPPTVTVLEGDSATLTCSASTGSPGPDVTWSKEGGTLIESlkvkhdngRTTQSSLLISNVTKE----DA------GTYT 70

                          90
                  ....*....|....
gi 1434110709 577 CVARNAVGNSSQSV 590
Cdd:pfam00047  71 CVVNNPGGSATLST 84

Immunoglobulin I-set domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1); The members here are composed of the immunoglobulin I-set (IgI) domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1). Human Lingo-1 is a central nervous system-specific transmembrane glycoprotein also known as LERN-1, which functions as a negative regulator of neuronal survival, axonal regeneration, and oligodendrocyte differentiation and myelination. Lingo-1 is a key component of the Nogo receptor signaling complex (RTN4R/NGFR) in RhoA activation responsible for some inhibition of axonal regeneration by myelin-associated factors. The ligand-binding ectodomain of human Lingo-1 contains a bimodular, kinked structure composed of leucine-rich repeat (LRR) and immunoglobulin (Ig)-like modules. Diseases associated with Lingo-1 include mental retardation, autosomal recessive 64 and essential tremor. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the Lingo-1 lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 510 VSVLEGGEAWLECSLRGGTPPAqLLWLGPQQQKVDPGTSGFMLHPEGAQLRlgiYDADPAHHRGTYQCVARNAVGNSSQS 589
Cdd:cd20969    12 VFVDEGHTVQFVCRADGDPPPA-ILWLSPRKHLVSAKSNGRLTVFPDGTLE---VRYAQVQDNGTYLCIAANAGGNDSMP 87

                  ....*
gi 1434110709 590 VLLEV 594
Cdd:cd20969    88 AHLHV 92

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 242 PVITMEPLGLTEEgfwASEREEVTLSCLAASNPPSHYVWLRDHTQVHT----------GPTYVIARAGRVHTGLYTCLAR 311
Cdd:cd20970     1 PVISTPQPSFTVT---AREGENATFMCRAEGSPEPEISWTRNGNLIIEfntryivrenGTTLTIRNIRRSDMGIYLCIAS 77

                  .
gi 1434110709 312 N 312
Cdd:cd20970    78 N 78

Fourth immunoglobulin (Ig)-like domain of hemolin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain of hemolin and similar proteins. Hemolin, an insect immunoglobulin superfamily (IgSF) member containing four Ig-like domains, is a lipopolysaccharide-binding immune protein induced during bacterial infection. Hemolin shares significant sequence similarity with the first four Ig-like domains of the transmembrane cell adhesion molecules (CAMs) of the L1 family. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The fourth Ig-like domain of hemolin is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 258 ASEREEVTLSCLAASNPPSHYVWLrdhtqvHTGPTyVIARAGRVH---------------TGLYTCLARNSYLDTRTQTT 322
Cdd:cd20978    13 VKGGQDVTLPCQVTGVPQPKITWL------HNGKP-LQGPMERATvedgtltiinvqpedTGYYGCVATNEIGDIYTETL 85

                  ..
gi 1434110709 323 VQ 324
Cdd:cd20978    86 LH 87

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 520 LECSLRGgTPPAQLLWLGPQQQKVDPGTSGFMLHPEGAQLRlgIYDADPaHHRGTYQCVARNAVGNSSQS 589
Cdd:cd00096     3 LTCSASG-NPPPTITWYKNGKPLPPSSRDSRRSELGNGTLT--ISNVTL-EDSGTYTCVASNSAGGSASA 68

Immunoglobulin domain; Members of the immunoglobulin superfamily are found in hundreds of proteins of different functions. Examples include antibodies, the giant muscle kinase titin and receptor tyrosine kinases. Immunoglobulin-like domains may be involved in protein-protein and protein-ligand interactions.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1434110709 161 EGASVVATCAVREGTEPVTFAWQHRAPRGLGEALVGVTEPL-----FQLDPVNRTHLGWYMCSASNS 222
Cdd:pfam00047  10 EGDSATLTCSASTGSPGPDVTWSKEGGTLIESLKVKHDNGRttqssLLISNVTKEDAGTYTCVVNNP 76

Immunoglobulin domain of human Synaptic Adhesion-Like Molecule 5 (SALM5) and similar proteins; member of the I-set of IgSF domains; This group contains the immunoglobulin domain of human Synaptic Adhesion-Like Molecule 5 (SALM5) and similar proteins. The SALM (for synaptic adhesion-like molecules; also known as Lrfn for leucine-rich repeat and fibronectin type III domain containing) family of adhesion molecules consists of five known members: SALM1/Lrfn2, SALM2/Lrfn1, SALM3/Lrfn4, SALM4/Lrfn3, and SALM5/Lrfn5. SALMs share a similar domain structure, containing leucine-rich repeats (LRRs), an immunoglobulin (Ig) domain, and a fibronectin III (FNIII) domain, followed by a transmembrane domain and a C-terminal PDZ-binding motif. SALM5 is implicated in autism spectrum disorders (ASDs) and schizophrenia, induces presynaptic differentiation in contacting axons. SALM5 interacts with the Ig domains of LAR (Leukocyte common Antigen-Related) family receptor protein tyrosine phosphatases (LAR-RPTPs; LAR, PTPdelta, and PTPsigma). In addition, PTPdelta is implicated in ASDs, ADHD, bipolar disorder, and restless leg syndrome. Studies have shown that LAR-RPTPs are novel and splicing-dependent presynaptic ligands for SALM5, and that they mediate SALM5-dependent presynaptic differentiation. Furthermore, SALM5 maintains AMPA receptor (AMPAR)-mediated excitatory synaptic transmission through mechanisms involving the interaction of SALM5 with LAR-RPTPs. This group belongs to the I-set of immunoglobulin superfamily (IgSF) domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 508 PRVSVLEGGEAWLECSLRGGTPPAqLLWLGPqQQKVDPGTSGFMLHPEGAqLRLGIYDADPAhhrGTYQCVARNAVGNSS 587
Cdd:cd05764     8 HELRVLEGQRATLRCKARGDPEPA-IHWISP-EGKLISNSSRTLVYDNGT-LDILITTVKDT---GAFTCIASNPAGEAT 81

                  ....*..
gi 1434110709 588 QSVLLEV 594
Cdd:cd05764    82 ARVELHI 88

First immunoglobulin (Ig) domain of contactin-5; member of the I-set of Ig superfamily domains; The members here are composed of the first immunoglobulin (Ig) domain of the neural cell adhesion molecule contactin-5. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains, anchored to the membrane by glycosylphosphatidylinositol. The different contactins show different expression patterns in the central nervous system. In rats, a lack of contactin-5 (NB-2) results in an impairment of the neuronal activity in the auditory system. Contactin-5 is expressed specifically in the postnatal nervous system, peaking at about 3 weeks postnatal. Contactin-5 is highly expressed in the adult human brain in the occipital lobe and in the amygdala; lower levels of expression have been detected in the corpus callosum, caudate nucleus, and spinal cord. This group belongs to the I-set of IgSF domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1434110709 259 SEREEVTLSCLAASNPPSHYVWLRDHTQVHTGPTY---------VIARAGRV-HTGLYTCLARNSY 314
Cdd:cd05848    17 SDEKKVILNCEARGNPVPTYRWLRNGTEIDTESDYryslidgnlIISNPSEVkDSGRYQCLATNSI 82

Second Ig-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the titin Z1z2 lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1434110709 259 SEREEVTLSCLAASNPPSHYVWLRDHTQVHTGPTYVIARAGRVH-----------TGLYTCLARNS 313
Cdd:cd20972    14 AEGSKVRLECRVTGNPTPVVRWFCEGKELQNSPDIQIHQEGDLHsliiaeafeedTGRYSCLATNS 79

Immunoglobulin (Ig)-like domain at the C-terminus of semaphorins; The members here are composed of the immunoglobulin (Ig)-like domain in semaphorins. Semaphorins are transmembrane protein that have important roles in a variety of tissues. Functionally, semaphorins were initially characterized for their importance in the development of the nervous system and in axonal guidance. Later they have been found to be important for the formation and functioning of the cardiovascular, endocrine, gastrointestinal, hepatic, immune, musculoskeletal, renal, reproductive, and respiratory systems. Semaphorins function through binding to their receptors and transmembrane semaphorins also serves as receptors themselves. Although molecular mechanism of semaphorins is poorly understood, the Ig-like domains may be involved in ligand binding or dimerization.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 505 VAEPRVSVLEGGEAWLECSLRGGTPPAQLLWLGPQQQKVDPGTsgFMLHPEGAqlrLGIYDADPAhHRGTYQCVARNAV- 583
Cdd:cd04979     1 TSFKQISVKEGDTVILSCSVKSNNAPVTWIHNGKKVPRYRSPR--LVLKTERG---LLIRSAQEA-DAGVYECHSGERVl 74

                          90
                  ....*....|..
gi 1434110709 584 GNSSQSVLLEVL 595
Cdd:cd04979    75 GSTLRSVTLHVL 86

Second Ig-like domain of Junctional adhesion molecule-1 (JAM1); a member of the I-set of IgSF domains; The members here are composed of the second Ig-like domain of Junctional adhesion molecule-1 (JAM1). JAM1 is an immunoglobulin superfamily (IgSF) protein with two Ig-like domains in its extracellular region; it plays a role in the formation of endothelial and epithelial tight junction and acts as a receptor for mammalian reovirus sigma-1. The IgSF is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The second Ig-like domain of JAM1 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, the A strand of the I-set is discontinuous but lacks a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1434110709 511 SVLEGGEAWLECSLRGGTPPAQLLW-----LGPQQQKVDPG--TSGFMLHPEGAQLrlgIYDADPAHHRGTYQCVARNAV 583
Cdd:cd20950     8 SATIGNRAVLTCSEPDGSPPSEYTWfkdgvVMPTNPKSTRAfsNSSYSLDPTTGEL---VFDPLSASDTGEYSCEARNGY 84

                          90
                  ....*....|...
gi 1434110709 584 GNS--SQSVLLEV 594
Cdd:cd20950    85 GTPmrSNAVRMEA 97

Fourth immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin domain of the Drosophila melanogaster Down syndrome cell adhesion molecule (DSCAM) protein and similar proteins. Down syndrome cell adhesion molecule (DSCAM) is a cell adhesion molecule that plays critical roles in neural development, including axon guidance and branching, axon target recognition, self-avoidance and synaptic formation. DSCAM belongs to the immunoglobulin superfamily and contributes to defects in the central nervous system in Down syndrome patients. Vertebrate DSCAMs differ from Drosophila Dscam1 in that they lack the extensive alternative splicing that occurs in the insect gene. Drosophila melanogaster Dscam has 38,016 isoforms generated by the alternative splicing of four variable exon clusters, which allows every neuron in the fly to display a distinctive set of Dscam proteins on its cell surface. Drosophila Dscam1 is a cell-surface protein that plays important roles in neural development and axon tiling of neurons. It is shown that thousands of isoforms bind themselves through specific homophilic (self-binding) interactions, a process which mediates cellular self-recognition. Drosophila Dscam2 is also alternatively spliced and plays a key role in the development of two visual system neurons, monopolar cells L1 and L2. This group is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1434110709 264 VTLSCLAASNPPSHYVWLRDHTQVHTGPTY----VIARAGRV------------HTGLYTCLARNS 313
Cdd:cd20956    19 VSLKCVASGNPLPQITWTLDGFPIPESPRFrvgdYVTSDGDVvsyvnissvrveDGGEYTCTATND 84