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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782  20 LTLVAPSSVF-EGDSIVLKCQGEQNWKIQKMAYHKDNKELSVFKKFSDFLIQSAVLSDSGNYFCStkGQLFLWDKTSNIV 98
Cdd:cd05753     2 LLLQAPSAVVfEGEPLTLRCHGWKDKKVHKVTYYKDGKALKFSYENSNFSIPQATLSDSGSYHCS--GTVRIKRRSSESV 79

                  ....
gi 1034561782  99 KIKV 102
Cdd:cd05753    80 NITV 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782 108 RPVLTAS--SFQPIEGGPVSLKCETRLSPQrLDVQlqfcFFRENQVLGSGWSSSPE-------LQISAVWSEDTGSYWCK 178
Cdd:pfam13927   1 KPVITVSpsSVTVREGETVTLTCEATGSPP-PTIT----WYKNGEPISSGSTRSRSlsgsnstLTISNVTRSDAGTYTCV 75

                  ..
gi 1034561782 179 AE 180
Cdd:pfam13927  76 AS 77

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782  20 LTLVAPSSVF-EGDSIVLKCQGEQNWKIQKMAYHKDNKELSVFKKFSDFLIQSAVLSDSGNYFCStkGQLFLWDKTSNIV 98
Cdd:cd05753     2 LLLQAPSAVVfEGEPLTLRCHGWKDKKVHKVTYYKDGKALKFSYENSNFSIPQATLSDSGSYHCS--GTVRIKRRSSESV 79

                  ....
gi 1034561782  99 KIKV 102
Cdd:cd05753    80 NITV 83

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1034561782  216 VTEGQKLILLCSVAGgTGNVTFSWYREATGTSMGKK----TQRSLSAELEIPAVKESDAGKYYCRADNGHVPIQSKV 288
Cdd:smart00410   6 VKEGESVTLSCEASG-SPPPEVTWYKQGGKLLAESGrfsvSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGT 81

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1034561782 208 EIRAPGGQvtEGQKLILLCSVAGGTGNVTFSWYREatGTSMGKKTQRSL-------SAELEIPAVKESDAGKYYCRADN 279
Cdd:cd05750     5 EMKSQTVQ--EGSKLVLKCEATSENPSPRYRWFKD--GKELNRKRPKNIkirnkkkNSELQINKAKLEDSGEYTCVVEN 79

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

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1034561782   27 SVFEGDSIVLKCQGEQN--------WKIQKMAYHKDNKELSVFKKFSDFLIQSAVLSDSGNYFC 82
Cdd:smart00410   5 TVKEGESVTLSCEASGSpppevtwyKQGGKLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTC 68

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782  20 LTLVAPSSVF-EGDSIVLKCQGEQNWKIQKMAYHKDNKELSVFKKFSDFLIQSAVLSDSGNYFCStkGQLFLWDKTSNIV 98
Cdd:cd05753     2 LLLQAPSAVVfEGEPLTLRCHGWKDKKVHKVTYYKDGKALKFSYENSNFSIPQATLSDSGSYHCS--GTVRIKRRSSESV 79

                  ....
gi 1034561782  99 KIKV 102
Cdd:cd05753    80 NITV 83

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1034561782 216 VTEGQKLILLCSVAGGTGNvTFSWYR---EATGTSMGKKTQRSLSAELEIPAVKESDAGKYYCRADN 279
Cdd:pfam13927  13 VREGETVTLTCEATGSPPP-TITWYKngePISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

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 1034561782 212 PGGQVTEGQKLILLCSVAGGTGNVTFSWYREAT----GTSMGKKTQRSLSAELEIPAVKESDAGKYYCRADNGHVPIQSK 287
Cdd:pfam00047   4 PTVTVLEGDSATLTCSASTGSPGPDVTWSKEGGtlieSLKVKHDNGRTTQSSLLISNVTKEDAGTYTCVVNNPGGSATLS 83

                  .
gi 1034561782 288 V 288
Cdd:pfam00047  84 T 84

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1034561782 208 EIRAPGGQvtEGQKLILLCSVAGGTGNVTFSWYREatGTSMGKKTQRSL-------SAELEIPAVKESDAGKYYCRADN 279
Cdd:cd05750     5 EMKSQTVQ--EGSKLVLKCEATSENPSPRYRWFKD--GKELNRKRPKNIkirnkkkNSELQINKAKLEDSGEYTCVVEN 79

Immunoglobulin (Ig) constant domain of the complement receptor of the immunoglobulin superfamily (CRIg); The members here are composed of the Immunoglobulin (Ig) constant domain of the complement receptor of the immunoglobulin superfamily (CRIg). The N-terminal domain of CRIg (also referred to as Z39Ig and V-set and Ig domain-containing 4 (VSIG4)) belongs to the IgV family of immunoglobulin-like domains while the C-terminal domain of CRIg belongs to the IgC family of immunoglobulin-like domains. CRIg plays a role in the complement system, an inhibitor of the alternative pathway convertases, and a negative regulator of T cell activation. 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 such as T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins such as 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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1034561782  27 SVFEGDSIVLKCQGEQNWKIQKMAYHK--DNKELSVFKKFSDFLIQSAVLSDSGNYFCSTKGQLFLwDKTSNIVKIKVQ 103
Cdd:cd16082     9 TVPQGMRISLQCQAWGSPPISYVWYKEqtNNQEPIKVAALSTLLFKPAVVADSGSYFCTAKGRVGS-EQRSDIVKFVVK 86

Immunoglobulin I-set domain;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1034561782 215 QVTEGQKLILLCSVAGgTGNVTFSWYR---EATGTSMGKKTQRSLSAELEIPAVKESDAGKYYCRADN 279
Cdd:pfam07679  11 EVQEGESARFTCTVTG-TPDPEVSWFKdgqPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATN 77

First 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 first 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 first 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 Ig 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, including vascular (VCAM), intercellular (ICAM), neural (NCAM) and mucosal addressin (MADCAM) cell adhesion molecules, as well as junction adhesion molecules (JAM).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782 218 EGQKLILLCSVAGGTGNVTFSWYREATGTSMGKK--TQRSLSAELEIPAVKESDAGKYYCRADNGHVPIQSKVvnIPVRR 295
Cdd:cd20979    14 EGQPTVLECVTEGGDQGVKYSWLKDGKSFNWQEHnvAQRKDEGSLVFLKPQASDEGQYQCFAETPAGVASSRV--ISFRR 91

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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782 216 VTEGQKLILLCSVAGGTGNVTFSWYREATGTSMGKKTQRSLS----------AELEIPAVKESDAGKYYCRADNGH-VPI 284
Cdd:cd20950     9 ATIGNRAVLTCSEPDGSPPSEYTWFKDGVVMPTNPKSTRAFSnssysldpttGELVFDPLSASDTGEYSCEARNGYgTPM 88

                  ....*....
gi 1034561782 285 QSKVVNIPV 293
Cdd:cd20950    89 RSNAVRMEA 97

Immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1; The members here are composed of the immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. NRG-1 belongs to the neuregulin gene family which is comprised of four genes. This group represents NRG-1. NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, and heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. The NRG-1 protein binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. NRG-1 has multiple functions, for example, in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1034561782 215 QVTEGQKLILLCSVAGGTGNVTFSWYReaTGTSMGKKTQ--------RSLSAELEIPAVKESDAGKYYCRADN 279
Cdd:cd05895    10 EVAAGSKLVLRCETSSEYPSLRFKWFK--NGKEINRKNKpenikiqkKKKKSELRINKASLADSGEYMCKVSS 80

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1034561782  27 SVFEGDSIVLKCQGEQNWKIQKMAYHKDNKELSVF----------KKFSDFLIQSAVLSDSGNYFCSTKGQL 88
Cdd:cd05750    10 TVQEGSKLVLKCEATSENPSPRYRWFKDGKELNRKrpknikirnkKKNSELQINKAKLEDSGEYTCVVENIL 81

Second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of Fcgamma-receptors (FcgammaRs). Interactions between IgG and FcgammaR are important to the initiation of cellular and humoral response. IgG binding to FcgammaR leads to a cascade of signals and ultimately to functions such as antibody-dependent-cellular-cytotoxicity (ADCC), endocytosis, phagocytosis, release of inflammatory mediators, etc. FcgammaR has two Ig-like domains. This group also contains FcepsilonRI which binds IgE with high affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782 207 LEIRAPGGQVTEGQKLILLCSVAGGTGNVTFSWYREatgtsmGKKTQRS-LSAELEIPAVKESDAGKYYCRADNGHVPIQ 285
Cdd:cd05753     2 LLLQAPSAVVFEGEPLTLRCHGWKDKKVHKVTYYKD------GKALKFSyENSNFSIPQATLSDSGSYHCSGTVRIKRRS 75

                  ....*...
gi 1034561782 286 SKVVNIPV 293
Cdd:cd05753    76 SESVNITV 83

Sixth 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 sixth 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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1034561782 214 GQVTEGQKLILLCSVAGGTGNVTFSWYREAT------GTSMGKKTQRSLSaeLEIPAVKESDAGKYYCRADN 279
Cdd:cd20959    12 GAAQVGMRAQLHCGVPGGDLPLNIRWTLDGQpisddlGITVSRLGRRSSI--LSIDSLEASHAGNYTCHARN 81

Third immunoglobulin (Ig) domain of contactin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig) domain of contactins. Contactins are neural cell adhesion molecules and are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. The first four Ig domains form the intermolecular binding fragment, which arranges as a compact U-shaped module via contacts between Ig domains 1 and 4, and between Ig domains 2 and 3. Contactin-2 (TAG-1, axonin-1) may play a part in the neuronal processes of neurite outgrowth, axon guidance and fasciculation, and neuronal migration. This group also includes contactin-1 and contactin-5. The different contactins show different expression patterns in the central nervous system. During development and in adulthood, contactin-2 is transiently expressed in subsets of central and peripheral neurons. Contactin-5 is expressed specifically in the rat postnatal nervous system, peaking at about 3 weeks postnatal, and a lack of contactin-5 (NB-2) results in an impairment of neuronal activity in the rat auditory system. Contactin-5 is highly expressed in the adult human brain in the occipital lobe and in the amygdala. Contactin-1 is differentially expressed in tumor tissues and may, through a RhoA mechanism, facilitate invasion and metastasis of human lung adenocarcinoma. This group belongs to the I-set of IgSF domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1034561782 219 GQKLILLCsVAGGTGNVTFSWyREATGTSMGKKTQRSLSAELEIPAVKESDAGKYYCRADN 279
Cdd:cd04968    16 GQTVTLEC-FALGNPVPQIKW-RKVDGSPSSQWEITTSEPVLEIPNVQFEDEGTYECEAEN 74

Seventh 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 seventh 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1034561782 216 VTEGQKLILLCSvAGGTGNVTFSWyREATGTSMGkkTQRSLSAE----------LEIPAVKESDAGKYYCRADNGHVPIQ 285
Cdd:cd20954    13 VAAGQDVMLHCQ-ADGFPTPTVTW-KKATGSTPG--EYKDLLYDpnvrilpngtLVFGHVQKENEGHYLCEAKNGIGSGL 88

                  ....*...
gi 1034561782 286 SKVVNIPV 293
Cdd:cd20954    89 SKVIFLKV 96