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 1843657976 135 PTVNIPSSATIGNRAVLTCSEQDGSPPSEYTWFKDGIVMPTNPKSTRAFSNSSYVLNPTTGELVFDPLSASDTGEYSCEA 214
Cdd:cd20950     1 PTVNIPSSATIGNRAVLTCSEPDGSPPSEYTWFKDGVVMPTNPKSTRAFSNSSYSLDPTTGELVFDPLSASDTGEYSCEA 80

                          90
                  ....*....|....*..
gi 1843657976 215 RNGYGTPMTSNAVRMEA 231
Cdd:cd20950    81 RNGYGTPMRSNAVRMEA 97

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 1843657976 135 PTVNIPSSATIGNRAVLTCSEQDGSPPSEYTWFKDGIVMPTNPKSTRAFSNSSYVLNPTTGELVFDPLSASDTGEYSCEA 214
Cdd:cd20950     1 PTVNIPSSATIGNRAVLTCSEPDGSPPSEYTWFKDGVVMPTNPKSTRAFSNSSYSLDPTTGELVFDPLSASDTGEYSCEA 80

                          90
                  ....*....|....*..
gi 1843657976 215 RNGYGTPMTSNAVRMEA 231
Cdd:cd20950    81 RNGYGTPMRSNAVRMEA 97

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976   36 PEVRIPENNPVKLSCAYSGFSSPRVEWKFDQGdttRLVCYNNKITASYEDRVTFLptgiTFKSVTREDTGTYTCMVSEEG 115
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGG---KLLAESGRFSVSRSGSTSTL----TISNVTPEDSGTYTCAATNSS 74

                           90
                   ....*....|
gi 1843657976  116 GNSYGEVKVK 125
Cdd:smart00410  75 GSASSGTTLT 84

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1843657976  142 SATIGNRAVLTCsEQDGSPPSEYTWFKDGIVMPTNPKSTRAFSNSsyvlnpTTGELVFDPLSASDTGEYSCEARNGYGT 220
Cdd:smart00410   5 TVKEGESVTLSC-EASGSPPPEVTWYKQGGKLLAESGRFSVSRSG------STSTLTISNVTPEDSGTYTCAATNSSGS 76

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 1843657976 135 PTVNIPSSATIGNRAVLTCSEQDGSPPSEYTWFKDGIVMPTNPKSTRAFSNSSYVLNPTTGELVFDPLSASDTGEYSCEA 214
Cdd:cd20950     1 PTVNIPSSATIGNRAVLTCSEPDGSPPSEYTWFKDGVVMPTNPKSTRAFSNSSYSLDPTTGELVFDPLSASDTGEYSCEA 80

                          90
                  ....*....|....*..
gi 1843657976 215 RNGYGTPMTSNAVRMEA 231
Cdd:cd20950    81 RNGYGTPMRSNAVRMEA 97

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976   36 PEVRIPENNPVKLSCAYSGFSSPRVEWKFDQGdttRLVCYNNKITASYEDRVTFLptgiTFKSVTREDTGTYTCMVSEEG 115
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGG---KLLAESGRFSVSRSGSTSTL----TISNVTPEDSGTYTCAATNSS 74

                           90
                   ....*....|
gi 1843657976  116 GNSYGEVKVK 125
Cdd:smart00410  75 GSASSGTTLT 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 1843657976 149 AVLTCSEQdGSPPSEYTWFKDGIVMPTNPKSTRAFSNSSyvlnpttGELVFDPLSASDTGEYSCEARNGYGTPMTSNA 226
Cdd:cd00096     1 VTLTCSAS-GNPPPTITWYKNGKPLPPSSRDSRRSELGN-------GTLTISNVTLEDSGTYTCVASNSAGGSASASV 70

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 1843657976 143 ATIGNRAVLTCSEQDGSPPSEYTWFKDGIVMPTNpkstRAFSNSSyvLNPTTGELVFDPLSASDTGEYSCEARNGYG 219
Cdd:cd20959    14 AQVGMRAQLHCGVPGGDLPLNIRWTLDGQPISDD----LGITVSR--LGRRSSILSIDSLEASHAGNYTCHARNSAG 84

Immunoglobulin V-set domain; This domain is found in antibodies as well as neural protein P0 and CTL4 amongst others.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976  34 SEPEVRIPENNPVKLSCAYSGFSS---PRVEWKFDQGDTTRLVC---YNNKITAS-YEDRVTFLPTG------ITFKSVT 100
Cdd:pfam07686   2 TPREVTVALGGSVTLPCTYSSSMSeasTSVYWYRQPPGKGPTFLiayYSNGSEEGvKKGRFSGRGDPsngdgsLTIQNLT 81

                          90       100
                  ....*....|....*....|....*....
gi 1843657976 101 REDTGTYTCMVSEEGGNSYGEvKVKLIVL 129
Cdd:pfam07686  82 LSDSGTYTCAVIPSGEGVFGK-GTRLTVL 109

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 1843657976 137 VNIPSSATIGNRAVLTCSEQDGSPPSEYTWFKDGIVMPTNPKSTRAFSNSsyvlnpTTGELVFDPLSASDTGEYSCEARN 216
Cdd:pfam00047   2 APPTVTVLEGDSATLTCSASTGSPGPDVTWSKEGGTLIESLKVKHDNGRT------TQSSLLISNVTKEDAGTYTCVVNN 75

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 1843657976  46 VKLSCAYSGFSSPRVEWKFDQGDTTrlvcynnkiTASYEDRVTFLPTG-ITFKSVTREDTGTYTCMVSEEGG 116
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLP---------PSSRDSRRSELGNGtLTISNVTLEDSGTYTCVASNSAG 63

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976  38 VRIPENNPVKLSCAYSGFSSPRVEWKFDQGDTTRlvcyNNKITASYEDRVTFLptgiTFKSVTREDTGTYTCMVSeeggN 117
Cdd:pfam07679  10 VEVQEGESARFTCTVTGTPDPEVSWFKDGQPLRS----SDRFKVTYEGGTYTL----TISNVQPDDSGKYTCVAT----N 77

                          90
                  ....*....|...
gi 1843657976 118 SYGEVKVKLIVLV 130
Cdd:pfam07679  78 SAGEAEASAELTV 90

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 1843657976 141 SSATIGNRAVLTCsEQDGSPPSEYTWFKdgiVMPTNPKSTRAFSNSSYVLNPTTGELVFDPLSASDTGEYSCEARNGYGT 220
Cdd:cd20954    11 ANVAAGQDVMLHC-QADGFPTPTVTWKK---ATGSTPGEYKDLLYDPNVRILPNGTLVFGHVQKENEGHYLCEAKNGIGS 86

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 1843657976  33 SSEPEVRIPENNPVKLSCAYSGFSS-PRVEWKFD--QGDTTRLVCYNNKITASyedrvtflpTGITFKSVTREDTGTYTC 109
Cdd:pfam00047   1 SAPPTVTVLEGDSATLTCSASTGSPgPDVTWSKEggTLIESLKVKHDNGRTTQ---------SSLLISNVTKEDAGTYTC 71

                          90
                  ....*....|....*
gi 1843657976 110 MVSEEGGNSYGEVKV 124
Cdd:pfam00047  72 VVNNPGGSATLSTSL 86

Immunoglobulin (Ig)-like domain of human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) domains 2, 4, and 6, and similar domains; The members here are composed of the second, fourth, and sixth immunoglobulin (Ig)-like domains in human carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) protein subfamily. 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. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions; it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two [D1, D4] or four [D1-D4] Ig-like domains on the cell surface.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 134 KPTVNIPSSATIGNR--AVLTCSEQDgsPPSEYTWFKDGIVMPTNPKSTrafsnssyvLNPTTGELVFDPLSASDTGEYS 211
Cdd:cd05740     1 KPFISSNNSNPVEDKdaVTLTCEPET--QNTSYLWWFNGQSLPVTPRLT---------LSNGNRTLTLLNVTREDAGAYQ 69

                  ....*
gi 1843657976 212 CEARN 216
Cdd:cd05740    70 CEISN 74

Immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM) and similar proteins; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, or spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains NrCAM [Ng(neuronglia)CAM-related cell adhesion molecule], which is primarily expressed in the nervous system, and human neurofascin. This group belongs to the I-set of 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 lacks a C" strand.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 150 VLTCsEQDGSPPSEYTWFKDGIvmPTNPKStrafsNSSYVLNPTTGELVFDPLSASDT---GEYSCEARNGYGTPMTSNA 226
Cdd:cd05733    20 TIKC-EAKGNPQPTFRWTKDGK--FFDPAK-----DPRVSMRRRSGTLVIDNHNGGPEdyqGEYQCYASNELGTAISNEI 91

                  .
gi 1843657976 227 V 227
Cdd:cd05733    92 R 92

Immunoglobulin (Ig)-like domain of NrCAM (Ng (neuronglia) CAM-related cell adhesion molecule); member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the first immunoglobulin (Ig)-like domain of NrCAM (Ng (neuronglia) CAM-related cell adhesion molecule). NrCAM belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region, and an intracellular domain. NrCAM is primarily expressed in the nervous system.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 150 VLTCsEQDGSPPSEYTWFKDG--IVMPTNPKSTrafsnssyvLNPTTGELVFDPLSASDT----GEYSCEARNGYGTPMT 223
Cdd:cd05874    20 VIQC-EAKGKPPPSFSWTRNGthFDIDKDPKVT---------MKPNTGTLVINIMNGEKAeayeGVYQCTARNERGAAVS 89

                  ....
gi 1843657976 224 SNAV 227
Cdd:cd05874    90 NNIV 93

First immunoglobulin (Ig)-like domain of Tyro3 receptor tyrosine kinase (RTK), and similar domains; The members here are composed of the first immunoglobulin (Ig)-like domain of Tyro3 receptor tyrosine kinase (RTK). Tyro3 together with Axl and Mer form the Axl/Tyro3 family of receptor tyrosine kinases (RTKs). This family includes Axl (also known as Ark, Ufo, and Tyro7), Tyro3 (also known as Sky, Rse, Brt, Dtk, and Tif), and Mer (also known as Nyk, c-Eyk, and Tyro12). Axl/Tyro3 family receptors have an extracellular portion with two Ig-like domains followed by two fibronectin-types III (FNIII) domains, a membrane-spanning single helix, and a cytoplasmic tyrosine kinase domain. Axl, Tyro3 and Mer are widely expressed in adult tissues, though they show higher expression in the brain, in the lymphatic and vascular systems, and in the testis. Axl, Tyro3, and Mer bind the vitamin K dependent protein Gas6 with high affinity, and in doing so activate their tyrosine kinase activity. Axl/Gas6 signaling may play a part in cell adhesion processes, prevention of apoptosis, and cell proliferation.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976  37 EVRIPENNPVKLSCAYSGFSSPRVEWKFDQGDTTRLvcYNNKITASYEDRVTFLptgiTFKSVTREDTGTYTCMVsEEGG 116
Cdd:cd20961     2 KLTVSQGQPVKLNCSVEGMEEPDIQWVKDGAVVQNL--DQLYIPVSEQHWIGFL----SLKSVERSDAGRYWCQV-EDGG 74

                  ..
gi 1843657976 117 NS 118
Cdd:cd20961    75 ET 76

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 140 PSSATIGNRAVLTCSeQDGSPPSEYTWFKDGIVMPTNPKStraFSNSsyvlnpttgelvfdpLSASDTGEYSCEARNGYG 219
Cdd:pfam13895   8 PTVVTEGEPVTLTCS-APGNPPPSYTWYKDGSAISSSPNF---FTLS---------------VSAEDSGTYTCVARNGRG 68

                  ....*....
gi 1843657976 220 tPMTSNAVR 228
Cdd:pfam13895  69 -GKVSNPVE 76

Fourth immunoglobulin (Ig)-like domain of L1, Ng-CAM (Neuron-glia CAM cell adhesion molecule), and NrCAM (Ng-CAM-related); The members here are composed of the fourth immunoglobulin (Ig)-like domain of L1, Ng-CAM (Neuron-glia CAM cell adhesion molecule), and NrCAM (Ng-CAM-related). These proteins belong to the L1 subfamily of cell adhesion molecules (CAMs) and are comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. These molecules are primarily expressed in the nervous system. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, or spastic paraplegia type 1, that involves abnormalities of axonal growth.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 140 PSSAT--IGNRAVLTCsEQDGSPPSEYTWFKDGIVMPTNPkstrafSNSSYVLNPTTgeLVFDPLSASDTGEYSCEARNG 217
Cdd:cd04978     6 PPSLVlsPGETGELIC-EAEGNPQPTITWRLNGVPIEPAP------EDMRRTVDGRT--LIFSNLQPNDTAVYQCNASNV 76

                  ....*....
gi 1843657976 218 YGtPMTSNA 226
Cdd:cd04978    77 HG-YLLANA 84

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1843657976 146 GNRAVLTCSEQDGSPPSEYTWFKDGivMPTNpkstraFSNSSYVLNPTTGELVFDPLSASDTGEYSCEARNGYG 219
Cdd:cd20979    15 GQPTVLECVTEGGDQGVKYSWLKDG--KSFN------WQEHNVAQRKDEGSLVFLKPQASDEGQYQCFAETPAG 80

Second immunoglobulin (Ig)-like domain of protein tyrosine kinase (PTK) 7; The members here are composed of the second immunoglobulin (Ig)-like domain in protein tyrosine kinase (PTK) 7, also known as CCK4. PTK7 is a subfamily of the receptor protein tyrosine kinase family, and is referred to as an RPTK-like molecule. RPTKs transduce extracellular signals across the cell membrane and play important roles in regulating cell proliferation, migration, and differentiation. PTK7 is organized as an extracellular portion having seven Ig-like domains, a single transmembrane region, and a cytoplasmic tyrosine kinase-like domain. PTK7 is considered a pseudokinase as it has several unusual residues in some of the highly conserved tyrosine kinase (TK) motifs; it is predicted to lack TK activity. PTK7 may function as a cell-adhesion molecule. PTK7 mRNA is expressed at high levels in placenta, melanocytes, liver, lung, pancreas, and kidney. PTK7 is overexpressed in several cancers, including melanoma and colon cancer lines.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 1843657976 148 RAVLTCsEQDGSPPSEYTWFKDGIVMPTnpkstrafSNSSYVLNPTTGELVFDPLSASDTGEYSCEARNGYGT 220
Cdd:cd05760    18 RVTLRC-HIDGHPRPTYQWFRDGTPLSD--------GQGNYSVSSKERTLTLRSAGPDDSGLYYCCAHNAFGS 81

Immunoglobulin (Ig)-like domain of class III semaphorin Sema3; The members here are composed of the immunoglobulin (Ig)-like domain of Sema3 and similar proteins. Semaphorins are classified based on structural features additional to the Sema domain. Sema3 is a Class III semaphorin that is secreted. It is a vertebrate class having a Sema domain, an Ig domain, a short basic domain. They have been shown to be axonal guidance cues and have a part in the regulation of the cardiovascular, immune, and respiratory systems. Sema3A, the prototype member of this class III subfamily, induces growth cone collapse and is an inhibitor of axonal sprouting. In perinatal rat cortex, it acts as a chemoattractant and functions to direct the orientated extension of apical dendrites. It may play a role, prior to the development of apical dendrites, in signaling the radial migration of newborn cortical neurons towards the upper layers. Sema3A selectively inhibits vascular endothelial growth factor receptor (VEGF)-induced angiogenesis and induces microvascular permeability. This group also includes Sema3B, -C, -D, -E, -G.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976  42 ENNPVKLSCAYSgfsSPR--VEWKFDQGDTTRlvcynnKITASYEDRVTFLPTGITFKSVTREDTGTYTCMvSEEGGNSY 119
Cdd:cd05871    11 EGNSTFLECLPK---SPQatVKWLFQRGGDQR------KEEVKSEERLIVTDRGLLLRSLQRSDAGVYTCQ-AVEHGFSQ 80

                          90
                  ....*....|..
gi 1843657976 120 GEVKVKLIVLVP 131
Cdd:cd05871    81 TLVKIRLHVIEP 92

Second immunoglobulin (Ig)-like domain of a Follistatin-related protein 5, and similar domains; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig)-like domain found in human Follistatin-related protein 5 (FSTL5) and a follistatin-like molecule encoded by the CNS-related Mahya gene. Mahya genes have been retained in certain Bilaterian branches during evolution. They are conserved in Hymenoptera and Deuterostomes, but are absent from other metazoan species such as fruit fly and nematode. Mahya proteins are secretory, with a follistatin-like domain (Kazal-type serine/threonine protease inhibitor domain and EF-hand calcium-binding domain), two Ig-like domains, and a novel C-terminal domain. Mahya may be involved in learning and memory and in processing of sensory information in Hymenoptera and vertebrates. Follistatin is a secreted, multidomain protein that binds activins with high affinity and antagonizes their signaling.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976  36 PEVRI-PENNP------VKLSCAYSGFSSPRVEWKFDQGDttrlvcynnkITASYEDRVTFLPTG--ITFKSVTREDTGT 106
Cdd:cd05736     1 PVIRVyPEFQAkepgveASLRCHAEGIPLPRVQWLKNGMD----------INPKLSKQLTLIANGseLHISNVRYEDTGA 70

                          90
                  ....*....|
gi 1843657976 107 YTCMVSEEGG 116
Cdd:cd05736    71 YTCIAKNEGG 80

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 1843657976 131 PPSKPTVNIPSSATIGNRAVLTCSEQdGSPPSEYTWFKDGivMPTNPKSTRafsnssYVLNPTTGELVFDPLSASDTGEY 210
Cdd:cd20976     1 APSFSSVPKDLEAVEGQDFVAQCSAR-GKPVPRITWIRNA--QPLQYAADR------STCEAGVGELHIQDVLPEDHGTY 71

                          90
                  ....*....|
gi 1843657976 211 SCEARNGYGT 220
Cdd:cd20976    72 TCLAKNAAGQ 81

Immunoglobulin (Ig)-like domain of vascular endothelial growth factor receptor (VEGFR); member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain of vascular endothelial growth factor receptor (VEGFR). The VEGFRs have an extracellular component with seven Ig-like domains, a transmembrane segment, and an intracellular tyrosine kinase domain interrupted by a kinase-insert domain. The VEGFR family consists of three members, VEGFR-1 (Flt-1), VEGFR-2 (KDR/Flk-1), and VEGFR-3 (Flt-4). VEGFRs bind VEGFs with high affinity at the Ig-like domains. VEGF-A is important to the growth and maintenance of vascular endothelial cells and to the development of new blood- and lymphatic-vessels in physiological and pathological states. VEGFR-2 is a major mediator of the mitogenic, angiogenic, and microvascular permeability-enhancing effects of VEGF-A. VEGFR-1 may play an inhibitory part in these processes by binding VEGF and interfering with its interaction with VEGFR-2. VEGFR-1 has a signaling role in mediating monocyte chemotaxis. VEGFR-1 and VEGFR-2 may mediate a chemotactic and a survival signal in hematopoietic stem cells or leukemia cells. VEGFR-3 has been shown to be involved in tumor angiogenesis and growth. This group belongs to the I-set of 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 1843657976  46 VKLSCAYSGFSSPRVEWkfdqgdttrlvcYNNKITASYEDRVtFLPTGITFKSVTREDTGTYTCMVSEEGGNSYGEVKVK 125
Cdd:cd04976    21 VRLPMKVKAYPPPEVVW------------YKDGLPLTEKARY-LTRHSLIIKEVTEEDTGNYTILLSNKQSNVFKNLTAT 87

                  ...
gi 1843657976 126 LIV 128
Cdd:cd04976    88 LVV 90

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 1843657976 146 GNRAVLTCSEQdGSPPSEYTWFKDGivmptnpkstRAFSNSSYVLNPTTGELVFDPLSASDTGEYSCEARNGYGTPMTSN 225
Cdd:cd20978    16 GQDVTLPCQVT-GVPQPKITWLHNG----------KPLQGPMERATVEDGTLTIINVQPEDTGYYGCVATNEIGDIYTET 84

                  ..
gi 1843657976 226 AV 227
Cdd:cd20978    85 LL 86

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 1843657976  45 PVKLSCAYSGFSSPRVEWkfdqgdttrlvCYNNKITASYEDRVTFLPTGITFKSVTREDTGTYTCMVSEEGGNSYGEVKV 124
Cdd:cd20978    18 DVTLPCQVTGVPQPKITW-----------LHNGKPLQGPMERATVEDGTLTIINVQPEDTGYYGCVATNEIGDIYTETLL 86

                  .
gi 1843657976 125 K 125
Cdd:cd20978    87 H 87

Third immunoglobulin (Ig)-like domain in Robo (roundabout) receptors; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig)-like domain in Robo (roundabout) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, Robo3), and three mammalian Slit homologs (Slit-1,Slit-2, Slit-3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit-1, Slit-2, and Slit-3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. This group belongs to the I-set of 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1843657976 142 SATIGNRAVLTCsEQDGSPPSEYTWFKDGIVMPTNpkstRAfsnssYVLNPTTgeLVFDPLSASDTGEYSCEARNGYGT 220
Cdd:cd05725     8 VVLVDDSAEFQC-EVGGDPVPTVRWRKEDGELPKG----RY-----EILDDHS--LKIRKVTAGDMGSYTCVAENMVGK 74

Fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region, and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 146 GNRAVLTCsEQDGSPPSEYTWFKDGI-VMPTNPKSTRAFSNssyvlnpttGELVFDPLSASDTGEYSCEARNGYGtPMTS 224
Cdd:cd05867    14 GETARLDC-QVEGIPTPNITWSINGApIEGTDPDPRRHVSS---------GALILTDVQPSDTAVYQCEARNRHG-NLLA 82

                  ..
gi 1843657976 225 NA 226
Cdd:cd05867    83 NA 84

Second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 - Necl-4; member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 (also known as cell adhesion molecule 3 or CADM3), Necl-2 (also known as CADM1), Necl-3 (also known as CADM2) and Necl-4 (also known as CADM4). These nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 through Necl-5). These have an extracellular region containing three Ig-like domains, one transmembrane region, and one cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains, is essential to cell-cell adhesion, and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1 and Necl-2 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues, and is a putative tumour suppressor gene, which is downregulated in aggressive neuroblastoma. Necl-3 has been shown to accumulate in tissues of the central and peripheral nervous system, where it is expressed in ependymal cells and myelinated axons. It is observed at the interface between the axon shaft and the myelin sheath. Necl-4 is expressed on Schwann cells, and plays a key part in initiating peripheral nervous system (PNS) myelination. Necl-4 participates in cell-cell adhesion and is proposed to play a role in tumor suppression.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|..
gi 1843657976 129 LVPPSKPTVNIPSSATI-GNRAVLTCSEQDGSPPSEYTWFKD 169
Cdd:cd05761     1 LGVPEKPVITGFTSPVVeGDEITLTCTTSGSKPAADIRWFKN 42

Immunoglobulin (Ig)-like ectodomain of the LRIG1 (Leucine-rich Repeats And Immunoglobulin-like Domains Protein 1) and similar proteins; member of the I-set of IgSF domains; The members here are composed of subgroup 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. 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. The ectodomain of LRIG1 has two distinct regions: the proposed 15 LRRs and three Ig-like domains closer to the membrane. LRIG1 has been reported to interact with many receptor tyrosine kinases, GDNF/c-Ret, E-cadherin, JAK/STAT, c-Met, and the EGFR family signaling systems. Immunoglobulin 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. The structure of the LRIG1 extracellular Ig domain lacks a C" strand and thus is better described as a member of the I-set of IgSF domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1843657976 139 IPSSATI--GNRAVLTCSEQdGSPPSEYTWFKDGivmPTNPKSTRafSNSSYVLnPTTGELVFDPLSASDTGEYSCEARN 216
Cdd:cd05763     5 TPHDITIraGSTARLECAAT-GHPTPQIAWQKDG---GTDFPAAR--ERRMHVM-PEDDVFFIVDVKIEDTGVYSCTAQN 77

                          90
                  ....*....|
gi 1843657976 217 GYGTpMTSNA 226
Cdd:cd05763    78 SAGS-ISANA 86

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.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1843657976 146 GNRAVLTCSEQdGSPPSEYTWFKDGIVMPTNPKstraFSNSSYVLNptTGELV----FDPLSASDTGEYSCEARNGYGT 220
Cdd:cd20956    16 GPSVSLKCVAS-GNPLPQITWTLDGFPIPESPR----FRVGDYVTS--DGDVVsyvnISSVRVEDGGEYTCTATNDVGS 87