Second immunoglobulin (Ig)-like C2-set domain of intercellular cell adhesion molecule 1 (ICAM-1), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of intercellular cell adhesion molecule 1 (ICAM-1; also known as domain of cluster of differentiation (CD) 54) and similar proteins. During the inflammation process, these molecules recruit leukocytes onto the vascular endothelium before extravasation to the injured tissues. ICAM-1 may be involved in organ targeted tumor metastasis. The interaction of ICAM-1 with leukocyte function-associated antigen-1 (LFA-1) plays a part in leukocyte-endothelial cell recognition. This group also contains ICAM-2 which also interacts with LFA-1. Transmigration of immature dendritic cells across resting endothelium is dependent on the interaction of ICAM-2 with, yet unidentified, ligand(s) on the dendritic cells. ICAM-1 has five Ig-like domains and ICAM-2 has two. ICAM-1 may also act as host receptor for viruses and parasites. The structures of this group show that the second Ig domain lacks a D strand and thus belonging to the C2-set of the IgSF

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583 119 RPDRVELMPLPPWQPVGENFTLSCRVPGAGPRASLTLTLLRGAQELIRRSFAGEPPRARGAVLTATVLARREDHGANFSC 198
Cdd:cd05755    1 PPERVELTPLPSWQPVGKNFTLRCRVPGGAPRASLTLVLLRGNETLHRETFGGAAPAPQPAEATFTVLARREDHGANFSC 80

                         90       100
                 ....*....|....*....|.
gi 189571583 199 RAELDLRPHGLGLFENSSAPR 219
Cdd:cd05755   81 LAELDLRPQGLNLFHNHSAPR 101

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583   759 VRPGGNFTLTCRAEAWPPAQISWR-------APPGALNIGLSSNNSTLSVAGAMGSHGGEYECAATNAHGRHARRITVRV 831
Cdd:smart00410   6 VKEGESVTLSCEASGSPPPEVTWYkqggkllAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLTV 85

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583  324 APLLTLSEPSVSEGQMVTVTCAAG--AQALVTLEGVPAAVPGQPAQLQLNATEnDDRRSFFCDATLDVDGETlikNRSAE 401
Cdd:pfam13895   1 KPVLTPSPTVVTEGEPVTLTCSAPgnPPPSYTWYKDGSAISSSPNFFTLSVSA-EDSGTYTCVARNGRGGKV---SNPVE 76

                  ...
gi 189571583  402 LRV 404
Cdd:pfam13895  77 LTV 79

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 189571583 581 PSNWTWVEGSGRLFSCEVDGKPQPSVKCvgsggATEGVLLPLAPPDPS----PRAPRIPRV--LAPGIYVCNATNRHGSV 654
Cdd:cd04978    6 PPSLVLSPGETGELICEAEGNPQPTITW-----RLNGVPIEPAPEDMRrtvdGRTLIFSNLqpNDTAVYQCNASNVHGYL 80

Second immunoglobulin (Ig)-like C2-set domain of intercellular cell adhesion molecule 1 (ICAM-1), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of intercellular cell adhesion molecule 1 (ICAM-1; also known as domain of cluster of differentiation (CD) 54) and similar proteins. During the inflammation process, these molecules recruit leukocytes onto the vascular endothelium before extravasation to the injured tissues. ICAM-1 may be involved in organ targeted tumor metastasis. The interaction of ICAM-1 with leukocyte function-associated antigen-1 (LFA-1) plays a part in leukocyte-endothelial cell recognition. This group also contains ICAM-2 which also interacts with LFA-1. Transmigration of immature dendritic cells across resting endothelium is dependent on the interaction of ICAM-2 with, yet unidentified, ligand(s) on the dendritic cells. ICAM-1 has five Ig-like domains and ICAM-2 has two. ICAM-1 may also act as host receptor for viruses and parasites. The structures of this group show that the second Ig domain lacks a D strand and thus belonging to the C2-set of the IgSF

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583 119 RPDRVELMPLPPWQPVGENFTLSCRVPGAGPRASLTLTLLRGAQELIRRSFAGEPPRARGAVLTATVLARREDHGANFSC 198
Cdd:cd05755    1 PPERVELTPLPSWQPVGKNFTLRCRVPGGAPRASLTLVLLRGNETLHRETFGGAAPAPQPAEATFTVLARREDHGANFSC 80

                         90       100
                 ....*....|....*....|.
gi 189571583 199 RAELDLRPHGLGLFENSSAPR 219
Cdd:cd05755   81 LAELDLRPQGLNLFHNHSAPR 101

N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54), ICAM-2 (CD102) and ICAM-3 (CD50); members of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) domain found in the N-terminus of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54), ICAM-2 (CD102), and ICAM-3 (CD50). ICAM-1, ICAM-2, and ICAM-3 mediate a variety of critical intercellular adhesion events in the immune system through interactions with their counter-receptors, the beta2-integrins LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), p150,95 (CD11c/CD18), and CD11d/CD18. The ICAMs are type I transmembrane glycoproteins belonging to the immunoglobulin superfamily (IgSF). The binding of the ICAM family members with the beta2-integrins physically stabilizes interactions between pairs of T and B cells, T cells and antigen-presenting cells (APCs), and brings effector cells such as cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells into close proximity to their target cells. All three ICAMs share a common polypeptide homology and structural motif, and the ability to bind LFA-1. The distinct functional role of each ICAM is affected by their relative affinities for LFA-1 (ICAM-1 > ICAM-2 > ICAM-3). ICAM-1 is expressed in most tissues at low levels, and expression is increased by inflammatory cytokines. In contrast, ICAM-2 is expressed predominantly on endothelium and leukocytes (except neutrophils), and its expression generally is not responsive to cytokines. ICAM-3 is expressed on leukocytes and Langerhans cells, but not on resting, cytokine-induced endothelium, or nonhematopoietic tissues.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 189571583  38 LQPRVAFVERGGSLWLNCSTNCPRPERGGLETSLRRNGTQRGLRWLARQLVDIREpETQPVCFFRC 103
Cdd:cd20944    3 VSPSKVILPRGGSLLVNCSTSCDQPELLGLETSLPKKLLLLPGNWKVYELSNVQE-DSQPMCYSNC 67

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 189571583  759 VRPGGNFTLTCRAEAWPPAQISWR------APPGALNIGLSSNNSTLSVAGAMGSHGGEYECAATN 818
Cdd:pfam13927  13 VREGETVTLTCEATGSPPPTITWYkngepiSSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 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 189571583   499 PERITWLEGTEASLSCVAHGVPPPDVICVRSGeLGAVIEG---------------LLRVAREHAGTYRCEATNPRGSAAK 563
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQG-GKLLAESgrfsvsrsgststltISNVTPEDSGTYTCAATNSSGSASS 79

                   ....*.
gi 189571583   564 NVAVTV 569
Cdd:smart00410  80 GTTLTV 85

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third 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, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 189571583 502 ITWLEGTEASLSCVAHGVPPPDVICVR-SGELGAVIEGL------LR---VAREHAGTYRCEATNPRGSAAKNVAVTVE 570
Cdd:cd05731    5 TMVLRGGVLLLECIAEGLPTPDIRWIKlGGELPKGRTKFenfnktLKienVSEADSGEYQCTASNTMGSARHTISVTVE 83

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583   416 PRSWTWPEGPEQTLRCEARGNPEPSVHCARSDGGAVLALG-------------LLGPVTRALSGTYRCKAANDQGEAVKD 482
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGrfsvsrsgststlTISNVTPEDSGTYTCAATNSSGSASSG 80

                   ....*
gi 189571583   483 VTLTV 487
Cdd:smart00410  81 TTLTV 85

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 189571583 423 EGPEQTLRCEARGNPEPSVHCARSDGgavlalGLLGPVTRAL----------------SGTYRCKAANDQGEAVKDVTLT 486
Cdd:cd05764   14 EGQRATLRCKARGDPEPAIHWISPEG------KLISNSSRTLvydngtldilittvkdTGAFTCIASNPAGEATARVELH 87

                 .
gi 189571583 487 V 487
Cdd:cd05764   88 I 88

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

                           10        20
                   ....*....|....*....|....*...
gi 189571583   713 QRVSREDAGTYHCVATNAHGTDSRTVTV 740
Cdd:smart00410  56 SNVTPEDSGTYTCAATNSSGSASSGTTL 83

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583  423 EGPEQTLRCEARGNPEPSV-------------HC--ARSDGGAVLalgLLGPVTRALSGTYRCKAANDQGEAVKDVTLTV 487
Cdd:pfam07679  14 EGESARFTCTVTGTPDPEVswfkdgqplrssdRFkvTYEGGTYTL---TISNVQPDDSGKYTCVATNSAGEAEASAELTV 90

Second immunoglobulin (Ig)-like C2-set domain of intercellular cell adhesion molecule 1 (ICAM-1), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of intercellular cell adhesion molecule 1 (ICAM-1; also known as domain of cluster of differentiation (CD) 54) and similar proteins. During the inflammation process, these molecules recruit leukocytes onto the vascular endothelium before extravasation to the injured tissues. ICAM-1 may be involved in organ targeted tumor metastasis. The interaction of ICAM-1 with leukocyte function-associated antigen-1 (LFA-1) plays a part in leukocyte-endothelial cell recognition. This group also contains ICAM-2 which also interacts with LFA-1. Transmigration of immature dendritic cells across resting endothelium is dependent on the interaction of ICAM-2 with, yet unidentified, ligand(s) on the dendritic cells. ICAM-1 has five Ig-like domains and ICAM-2 has two. ICAM-1 may also act as host receptor for viruses and parasites. The structures of this group show that the second Ig domain lacks a D strand and thus belonging to the C2-set of the IgSF

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583 119 RPDRVELMPLPPWQPVGENFTLSCRVPGAGPRASLTLTLLRGAQELIRRSFAGEPPRARGAVLTATVLARREDHGANFSC 198
Cdd:cd05755    1 PPERVELTPLPSWQPVGKNFTLRCRVPGGAPRASLTLVLLRGNETLHRETFGGAAPAPQPAEATFTVLARREDHGANFSC 80

                         90       100
                 ....*....|....*....|.
gi 189571583 199 RAELDLRPHGLGLFENSSAPR 219
Cdd:cd05755   81 LAELDLRPQGLNLFHNHSAPR 101

N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54), ICAM-2 (CD102) and ICAM-3 (CD50); members of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) domain found in the N-terminus of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54), ICAM-2 (CD102), and ICAM-3 (CD50). ICAM-1, ICAM-2, and ICAM-3 mediate a variety of critical intercellular adhesion events in the immune system through interactions with their counter-receptors, the beta2-integrins LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), p150,95 (CD11c/CD18), and CD11d/CD18. The ICAMs are type I transmembrane glycoproteins belonging to the immunoglobulin superfamily (IgSF). The binding of the ICAM family members with the beta2-integrins physically stabilizes interactions between pairs of T and B cells, T cells and antigen-presenting cells (APCs), and brings effector cells such as cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells into close proximity to their target cells. All three ICAMs share a common polypeptide homology and structural motif, and the ability to bind LFA-1. The distinct functional role of each ICAM is affected by their relative affinities for LFA-1 (ICAM-1 > ICAM-2 > ICAM-3). ICAM-1 is expressed in most tissues at low levels, and expression is increased by inflammatory cytokines. In contrast, ICAM-2 is expressed predominantly on endothelium and leukocytes (except neutrophils), and its expression generally is not responsive to cytokines. ICAM-3 is expressed on leukocytes and Langerhans cells, but not on resting, cytokine-induced endothelium, or nonhematopoietic tissues.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 189571583  38 LQPRVAFVERGGSLWLNCSTNCPRPERGGLETSLRRNGTQRGLRWLARQLVDIREpETQPVCFFRC 103
Cdd:cd20944    3 VSPSKVILPRGGSLLVNCSTSCDQPELLGLETSLPKKLLLLPGNWKVYELSNVQE-DSQPMCYSNC 67

N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54); member of the I-set of IgSF domains; The members here are composed of the N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54). The intercellular adhesion molecules ICAM-1, ICAM-2 (Cluster of Differentiation 102 or CD102) and ICAM-3 (Cluster of Differentiation 50 or CD50) mediate a variety of critical intercellular adhesion events in the immune system through interactions with their counter-receptors, the beta2-integrins LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), p150,95 (CD11c/CD18), and CD11d/CD18. The ICAMs are type I transmembrane glycoproteins belonging to the immunoglobulin superfamily (IgSF). The binding of the ICAM family members with the beta2-integrins physically stabilizes interactions between pairs of T and B cells, T cells and antigen-presenting cells (APCs), and brings effector cells such as cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells into close proximity to their target cells. All three ICAMs share a common polypeptide homology and structural motif, and the ability to bind LFA-1. The distinct functional role of each ICAM is affected by their relative affinities for LFA-1 (ICAM-1 > ICAM-2 > ICAM-3). ICAM-1 is expressed in most tissues at low levels, and expression is increased by inflammatory cytokines. In contrast, ICAM-2 is expressed predominantly on endothelium and leukocytes (except neutrophils), and its expression generally is not responsive to cytokines. ICAM-3 is expressed on leukocytes and Langerhans cells, but not on resting, cytokine-induced endothelium, or nonhematopoietic tissues.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 189571583  40 PRVAFVERGGSLWLNCSTNCPRPERGGLETSLRRNGTQRGLRWLARQLVDIREpETQPVCFFRC 103
Cdd:cd20996    6 PSKAILPRGGSVQVNCSTSCDQPLLLGLETPLPKKELLLGGNWKVFELSNVQE-DSQPMCYSNC 68

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the third 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, 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 the chicken neuron-glia cell adhesion molecule, Ng-CAM.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 189571583 762 GGNFTLTCRAEAWPPAQISWRAPPGAL---NIGLSSNNSTLSVAGAMGSHGGEYECAATNAHG--RHARRITV 829
Cdd:cd05876   10 GQSLVLECIAEGLPTPTVKWLRPSGPLppdRVKYQNHNKTLQLLNVGESDDGEYVCLAENSLGsaRHAYYVTV 82

N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-2 (Cluster of Differentiation 102 or CD102); member of the I-set of IgSF domains; The members here are composed of the N-terminal immunoglobulin domain of the intercellular adhesion molecules ICAM-2 (Cluster of Differentiation 102 or CD102). The intercellular adhesion molecules ICAM-1 (Cluster of Differentiation 54 or CD54), ICAM-2 and ICAM-3 (Cluster of Differentiation 50 or CD50) mediate a variety of critical intercellular adhesion events in the immune system through interactions with their counter-receptors, the beta2-integrins LFA-1 (CD11a/CD18), Mac-1 (CD11b/CD18), p150,95 (CD11c/CD18), and CD11d/CD18. The ICAMs are type I transmembrane glycoproteins belonging to the immunoglobulin superfamily (IgSF). The binding of the ICAM family members with the beta2-integrins physically stabilizes interactions between pairs of T and B cells, T cells and antigen-presenting cells (APCs), and brings effector cells such as cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells into close proximity to their target cells. All three ICAMs share a common polypeptide homology and structural motif, and the ability to bind LFA-1. The distinct functional role of each ICAM is affected by their relative affinities for LFA-1 (ICAM-1 > ICAM-2 > ICAM-3). ICAM-1 is expressed in most tissues at low levels, and expression is increased by inflammatory cytokines. In contrast, ICAM-2 is expressed predominantly on endothelium and leukocytes (except neutrophils), and its expression generally is not responsive to cytokines. ICAM-3 is expressed on leukocytes and Langerhans cells, but not on resting, cytokine-induced endothelium, or nonhematopoietic tissues.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583  33 PFWADLQprvaFVERGGSLWLNCSTNCPRPERGGLETSLRRNGTQRGLRWLARQLVDIREpETQPVCFFRCARRTLQARG 112
Cdd:cd20995    4 YIRSEKQ----IVEATESWEVNCSTSCAQPEVGGLETPTNKILLEEQAQWKHYLVSNVSH-DTVLLCHFTCSGKQESESF 78

                 ....*
gi 189571583 113 LIRTF 117
Cdd:cd20995   79 NISVY 83

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 189571583 759 VRPGGNFTLTCRAEAWPPAQISWRAPPGALNIG-----LSSNNSTLSVAGAMGSHGGEYECAATN-AHGRHARRITVRV 831
Cdd:cd20970   14 AREGENATFMCRAEGSPEPEISWTRNGNLIIEFntryiVRENGTTLTIRNIRRSDMGIYLCIASNgVPGSVEKRITLQV 92

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583  324 APLLTLSEPSVSEGQMVTVTCAAG--AQALVTLEGVPAAVPGQPAQLQLNATEnDDRRSFFCDATLDVDGETlikNRSAE 401
Cdd:pfam13895   1 KPVLTPSPTVVTEGEPVTLTCSAPgnPPPSYTWYKDGSAISSSPNFFTLSVSA-EDSGTYTCVARNGRGGKV---SNPVE 76

                  ...
gi 189571583  402 LRV 404
Cdd:pfam13895  77 LTV 79

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third 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, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 189571583 762 GGNFTLTCRAEAWPPAQISWRAPPGAL---NIGLSSNNSTLSVAGAMGSHGGEYECAATNAHGRHARRITVRV 831
Cdd:cd05731   10 GGVLLLECIAEGLPTPDIRWIKLGGELpkgRTKFENFNKTLKIENVSEADSGEYQCTASNTMGSARHTISVTV 82

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583   416 PRSWTWPEGPEQTLRCEARGNPEPSVHCARSDGGAVLALG-------------LLGPVTRALSGTYRCKAANDQGEAVKD 482
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGrfsvsrsgststlTISNVTPEDSGTYTCAATNSSGSASSG 80

                   ....*
gi 189571583   483 VTLTV 487
Cdd:smart00410  81 TTLTV 85

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 189571583  753 ASPPGGVRPGGNFTLTCRA-EAWPPAQISWRAPPGALNIGL-------SSNNSTLSVAGAMGSHGGEYECAATNAHGRHA 824
Cdd:pfam00047   2 APPTVTVLEGDSATLTCSAsTGSPGPDVTWSKEGGTLIESLkvkhdngRTTQSSLLISNVTKEDAGTYTCVVNNPGGSAT 81

                  ....*
gi 189571583  825 RRITV 829
Cdd:pfam00047  82 LSTSL 86

Immunoglobulin I-set domain;

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 189571583  759 VRPGGNFTLTCRAEAWPPAQISWR------APPGALNIGLSSNNSTLSVAGAMGSHGGEYECAATNAHG 821
Cdd:pfam07679  12 VQEGESARFTCTVTGTPDPEVSWFkdgqplRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAG 80

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        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583 759 VRPGGNFTLTCRAEAWPPAQISWR------APPGALNIG--LSSNN---STLSVAGAMGSHGGEYECAATNAHG--RHAR 825
Cdd:cd20956   13 LQPGPSVSLKCVASGNPLPQITWTldgfpiPESPRFRVGdyVTSDGdvvSYVNISSVRVEDGGEYTCTATNDVGsvSHSA 92

                 ....
gi 189571583 826 RITV 829
Cdd:cd20956   93 RINV 96

Fourth Ig domain of the neural cell adhesion molecule contactin-2, and similar domains; The members here are composed of the fourth Ig domain of the neural cell adhesion molecule contactin-2. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-2 (also called TAG-1, axonin-1) facilitates cell adhesion by homophilic binding between molecules in apposed membranes. The first four Ig domains form the intermolecular binding fragment which arranges as a compact U-shaped module by contacts between Ig domains 1 and 4, and domains 2 and 3. It has been proposed that a linear zipper-like array forms, from contactin-2 molecules alternatively provided by the two apposed membranes.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|..
gi 189571583 694 GRPSPGVRCSREGIPWPEQQRV------------SREDAGTYHCVATNAHGT 733
Cdd:cd05728   25 GNPRPAYRWLKNGQPLASENRIeveagdlritklSLSDSGMYQCVAENKHGT 76

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

                           10        20
                   ....*....|....*....|....*...
gi 189571583   713 QRVSREDAGTYHCVATNAHGTDSRTVTV 740
Cdd:smart00410  56 SNVTPEDSGTYTCAATNSSGSASSGTTL 83

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 189571583 760 RPGGNFTLTCRAEAWPPAQISWRappgaLNIGLSSNNSTLSVAGAMGSHGGEYECAATN-AHGR 822
Cdd:cd20948    8 LSGENLNLSCHAASNPPAQYSWT-----INGTFQTSSQELFLPAITENNEGTYTCSAHNsLTGK 66

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 189571583  423 EGPEQTLRCEARGNPEPSV-------------HC--ARSDGGAVLalgLLGPVTRALSGTYRCKAANDQGEAVKDVTLTV 487
Cdd:pfam07679  14 EGESARFTCTVTGTPDPEVswfkdgqplrssdRFkvTYEGGTYTL---TISNVQPDDSGKYTCVATNSAGEAEASAELTV 90

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the third 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, 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 the chicken neuron-glia cell adhesion molecule, Ng-CAM.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 189571583 505 LEGTEASLSCVAHGVPPPDVICVR-SGELGAVIEG---------LLRVAREHAGTYRCEATNPRGSAAKNVAVTVE 570
Cdd:cd05876    8 LRGQSLVLECIAEGLPTPTVKWLRpSGPLPPDRVKyqnhnktlqLLNVGESDDGEYVCLAENSLGSARHAYYVTVE 83

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 189571583  506 EGTEASLSCVAHGVPPPDVICVRSGElgAVIEG----LLRVAREHAGTYRCEATNPRGSA-AKNVAVTV 569
Cdd:pfam13895  13 EGEPVTLTCSAPGNPPPSYTWYKDGS--AISSSpnffTLSVSAEDSGTYTCVARNGRGGKvSNPVELTV 79

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. 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, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -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, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -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 is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 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 (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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 189571583 759 VRPGGNFTLTCRAEAWPPAQISWRAPpGALNIGLSS-----NNSTLSVAGAMGSHGGEYECAATNAHGRHARRITVRV 831
Cdd:cd20952   11 VAVGGTVVLNCQATGEPVPTISWLKD-GVPLLGKDErittlENGSLQIKGAEKSDTGEYTCVALNLSGEATWSAVLDV 87

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 189571583 491 PALDSVGCPERITWLEGTEASLSCVAHGVPPPDVICVRSGELgaVIEG--------------LLRVAREHAGTYRCEATN 556
Cdd:cd20970    1 PVISTPQPSFTVTAREGENATFMCRAEGSPEPEISWTRNGNL--IIEFntryivrengttltIRNIRRSDMGIYLCIASN 78

                         90
                 ....*....|....
gi 189571583 557 -PRGSAAKNVAVTV 569
Cdd:cd20970   79 gVPGSVEKRITLQV 92

Immunoglobulin domain I1 of the titin I-band and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain I1 of the titin I-band 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. 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 Ig I1 domain of the titin I-band 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 (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 189571583 694 GRPSPGVRCSREGIP------------WPEQ-------QRVSREDAGTYHCVATNAHGTDSRTVTVGVE 743
Cdd:cd20951   26 GKPDPEVKWYKNGVPidpssipgkykiESEYgvhvlhiRRVTVEDSAVYSAVAKNIHGEASSSASVVVE 94

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 189571583  505 LEGTEASLSC-VAHGVPPPDVICVRSGelGAVIEG----------------LLRVAREHAGTYRCEATNPRGSAAKNVAV 567
Cdd:pfam00047   9 LEGDSATLTCsASTGSPGPDVTWSKEG--GTLIESlkvkhdngrttqssllISNVTKEDAGTYTCVVNNPGGSATLSTSL 86

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 189571583 759 VRPGGNFTLTCRAEAWPPAQISWRAPPGALnIGLSS-----NNSTLSVAGAMGSHGGEYECAATNAHGRHARRITVRV 831
Cdd:cd05764   12 VLEGQRATLRCKARGDPEPAIHWISPEGKL-ISNSSrtlvyDNGTLDILITTVKDTGAFTCIASNPAGEATARVELHI 88

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        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 189571583 762 GGNFTLTCRAEAWPPAQISWRAPPGAL--NIGLSSNNSTLSVAGAMGSHGGEYECAATNAHGR--HARRITV 829
Cdd:cd04968   16 GQTVTLECFALGNPVPQIKWRKVDGSPssQWEITTSEPVLEIPNVQFEDEGTYECEAENSRGKdtVQGRIIV 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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 189571583 428 TLRCEARGNPEPSVHCAR---------------SDGGAVLalgLLGPVTRALSGTYRCKAANDQGEAV 480
Cdd:cd00096    2 TLTCSASGNPPPTITWYKngkplppssrdsrrsELGNGTL---TISNVTLEDSGTYTCVASNSAGGSA 66