Signal-regulatory protein (SIRP) immunoglobulin-like domain 3; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in Signal-Regulatory Protein (SIRP), domain 3 (C1 repeat 2). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three Immunoglobulin superfamily domains a single V-set and two C1-set IgSF domains. Their cytoplasmic tails that contain either ITIMs or transmembrane regions that have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs but also binds CD47, but with much less affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 246 VSPTVKVTQQSPTSMNQVNLTCRAERFYPEDLQLIWLENGNVSRNDTPKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTC 325
Cdd:cd16085     1 VPPTLEVTQQPTMVWNQVNVTCQVEKFYPQRLQLTWLENGNVSRTETPSTLTVNKDGTYNWTSWLLVNVSAHREDVVLTC 80

                          90
                  ....*....|....*.
gi 1907136872 326 QVKHDQQPAITRNHTV 341
Cdd:cd16085    81 QVEHDGQPAVTKNHTL 96

Signal-regulatory protein (SIRP) immunoglobulin-like domain 3; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in Signal-Regulatory Protein (SIRP), domain 3 (C1 repeat 2). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three Immunoglobulin superfamily domains a single V-set and two C1-set IgSF domains. Their cytoplasmic tails that contain either ITIMs or transmembrane regions that have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs but also binds CD47, but with much less affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 246 VSPTVKVTQQSPTSMNQVNLTCRAERFYPEDLQLIWLENGNVSRNDTPKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTC 325
Cdd:cd16085     1 VPPTLEVTQQPTMVWNQVNVTCQVEKFYPQRLQLTWLENGNVSRTETPSTLTVNKDGTYNWTSWLLVNVSAHREDVVLTC 80

                          90
                  ....*....|....*.
gi 1907136872 326 QVKHDQQPAITRNHTV 341
Cdd:cd16085    81 QVEHDGQPAVTKNHTL 96

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 1907136872  31 QPEKSVSVAAGDSTVLNCTLTSL--LPVGPIRWYRG--VGPSRLLIYSFAGEYVPRIR--NVSDTTKRNNMDFSIRISNV 104
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSmsEASTSVYWYRQppGKGPTFLIAYYSNGSEEGVKkgRFSGRGDPSNGDGSLTIQNL 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1907136872 105 TPADAGIYYCVKFqkgssePDTEIQSGGGTEVYVL 139
Cdd:pfam07686  81 TLSDSGTYTCAVI------PSGEGVFGKGTRLTVL 109

Immunoglobulin C1-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 136 VYVLAkPSPPEVSgpadrgipdQKVNFTCKSHGFSPRNITLKWFKDGQELHPLETTVNPS-GKNVSYNISSTVRVVLNSM 214
Cdd:pfam07654   1 VYVFP-PSPEELG---------KPNTLTCLVTGFYPPDITVTWLKNGQEVTEGVKTTPPSpNSDWTYQLSSYLTVTPSDW 70

                          90
                  ....*....|....*
gi 1907136872 215 DVNSKVICEVAHITL 229
Cdd:pfam07654  71 ESGDEYTCRVEHEGL 85

Immunoglobulin C1-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 250 VKVTQQSPTSMNQVN-LTCRAERFYPEDLQLIWLENGNVSRND-TPKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTCQV 327
Cdd:pfam07654   1 VYVFPPSPEELGKPNtLTCLVTGFYPPDITVTWLKNGQEVTEGvKTTPPSPNSDWTYQLSSYLTVTPSDWESGDEYTCRV 80

                  ..
gi 1907136872 328 KH 329
Cdd:pfam07654  81 EH 82

Signal-regulatory protein (SIRP) immunoglobulin-like domain 3; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in Signal-Regulatory Protein (SIRP), domain 3 (C1 repeat 2). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three Immunoglobulin superfamily domains a single V-set and two C1-set IgSF domains. Their cytoplasmic tails that contain either ITIMs or transmembrane regions that have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs but also binds CD47, but with much less affinity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 246 VSPTVKVTQQSPTSMNQVNLTCRAERFYPEDLQLIWLENGNVSRNDTPKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTC 325
Cdd:cd16085     1 VPPTLEVTQQPTMVWNQVNVTCQVEKFYPQRLQLTWLENGNVSRTETPSTLTVNKDGTYNWTSWLLVNVSAHREDVVLTC 80

                          90
                  ....*....|....*.
gi 1907136872 326 QVKHDQQPAITRNHTV 341
Cdd:cd16085    81 QVEHDGQPAVTKNHTL 96

Immunoglobulin variable domain (IgV); The members here are composed of the immunoglobulin variable domain (IgV). The IgV family contains the standard Ig superfamily V-set AGFCC'C"/DEB domain topology, and are components of immunoglobulin (Ig) and T cell receptors. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. In Ig, each chain is composed of one variable domain (IgV) and one or more constant domains (IgC); these names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. Within the variable domain, there are regions of even more variability called the hypervariable or complementarity-determining regions (CDRs) which are responsible for antigen binding. A predominant feature of most Ig domains is the disulfide bridge connecting 2 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" strands in the other.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  29 VTQPEKSVSVAAGDSTVLNCTLTSLLPVGPIRWYRGV-GPSRLLIYSFAGEYVPRIRNVSD---TTKRNNMDFSIRISNV 104
Cdd:cd00099     1 VTQSPRSLSVQEGESVTLSCEVSSSFSSTYIYWYRQKpGQGPEFLIYLSSSKGKTKGGVPGrfsGSRDGTSSFSLTISNL 80

                          90       100       110
                  ....*....|....*....|....*....|....
gi 1907136872 105 TPADAGIYYCVKFQKGSSEPDTeiqSGGGTEVYV 138
Cdd:cd00099    81 QPEDSGTYYCAVSESGGTDKLT---FGSGTRLTV 111

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 1907136872  31 QPEKSVSVAAGDSTVLNCTLTSL--LPVGPIRWYRG--VGPSRLLIYSFAGEYVPRIR--NVSDTTKRNNMDFSIRISNV 104
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSmsEASTSVYWYRQppGKGPTFLIAYYSNGSEEGVKkgRFSGRGDPSNGDGSLTIQNL 80

                          90       100       110
                  ....*....|....*....|....*....|....*
gi 1907136872 105 TPADAGIYYCVKFqkgssePDTEIQSGGGTEVYVL 139
Cdd:pfam07686  81 TLSDSGTYTCAVI------PSGEGVFGKGTRLTVL 109

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) alpha chain and similar proteins; The members here are composed of the immunoglobulin (Ig) variable domain of the alpha chain of alpha/beta T-cell antigen receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are composed of alpha and beta, or gamma and delta polypeptide chains with variable (V) and constant (C) regions. This group represents the variable domain of the alpha chain of TCRs and also includes the variable domain of delta chains of TCRs. Alpha/beta TCRs recognize antigen as peptide fragments presented by major histocompatibility complex (MHC) molecules. The variable domain of TCRs is responsible for antigen recognition, and is located at the N-terminus of the receptor. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  29 VTQPEKSVSVAAGDSTVLNCTLTSLLPVGpIRWYR---GVGPSRLLIYSFAGEYVPRIRnVSDTTKRNNMDFSIRISNVT 105
Cdd:cd04983     1 VTQSPQSLSVQEGENVTLNCNYSTSTFYY-LFWYRqypGQGPQFLIYISSDSGNKKKGR-FSATLDKSRKSSSLHISAAQ 78

                          90       100       110
                  ....*....|....*....|....*....|...
gi 1907136872 106 PADAGIYYCVKFQKGSSEpdtEIQSGGGTEVYV 138
Cdd:cd04983    79 LSDSAVYFCALSESGGTG---KLTFGKGTRLTV 108

Immunoglobulin C-Type;

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1907136872  262 QVNLTCRAERFYPEDLQLIWLENGNVSRNDT-PKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTCQVKH 329
Cdd:smart00407   1 KATLVCLVSGFYPPDITVTWLRNGQEVTEGVsTTDPLKNSDGTYFLSSYLTVPASTWESGDVYTCQVTH 69

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig) domain of major histocompatibility complex (MHC) class II beta chain. MHC class II molecules play a key role in the initiation of the antigen-specific immune reponse. These molecules have been shown to be expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice. The expression of these molecules has been shown to be induced in nonprofessional APCs such as keratinocyctes and they are also expressed on the surface of activated human T cells and on T cells from other species. The MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes. These peptides derive mostly from proteolytic processing via the endocytic pathway of antigens internalized by the APC. These peptides bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain has two globular domains (N- and C-terminal) and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 245 RVSPTVKVTQQSPTSMNQVN-LTCRAERFYPEDLQLIWLENGNVSRND-TPKNLTKNTDGTYNYtsLFLVNSSAHREDvV 322
Cdd:cd05766     1 RVQPSVKVSPTKTGPLEHPNlLVCSVTGFYPAEIEVKWFRNGQEETAGvVSTELIPNGDWTFQI--LVMLETTPRRGD-V 77

                          90
                  ....*....|....*...
gi 1907136872 323 FTCQVKHD--QQPaITRN 338
Cdd:cd05766    78 YTCQVEHSslQSP-LTVD 94

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872   34 KSVSVAAGDSTVLNCTLTSLlPVGPIRWYRGvgPSRLLIYSfageyvPRIrnvsdTTKRNNMDFSIRISNVTPADAGIYY 113
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGS-PPPEVTWYKQ--GGKLLAES------GRF-----SVSRSGSTSTLTISNVTPEDSGTYT 67

                           90       100
                   ....*....|....*....|....*.
gi 1907136872  114 C-VKFQKGSSEpdteiqsgGGTEVYV 138
Cdd:smart00410  68 CaATNSSGSAS--------SGTTLTV 85

Class Ib major histocompatibility complex (MHC) immunoglobulin domain of human leukocyte antigen H; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class Ib major histocompatibility complex (MHC) immunoglobulin domain of human leukocyte antigen H (HLA-H). HLA-H (also known as hereditary hemochromatosis protein; HFE) is a major histocompatibility complex (MHC) class I-like protein that is mutated in Hereditary Hemochromatosis. HFE is a protein of 343 amino acids that includes a signal peptide, an extracellular transferrin receptor-binding region (a1 and a2), an immunoglobulin-like domain (a3), a transmembrane region, and a short cytoplasmic tail. HFE binds beta-2-microglobulin to form a heterodimer expressed at the cell surface. It binds transferrin receptor (TFRC) in its extracellular alpha1-alpha2 domain. HFE plays an important part in the regulation of hepcidin expression in response to iron overload and the liver is important in the pathophysiology of HFE-associated hemochromatosis. Nine HFE splicing variants have been reported with transcripts lacking exon 2 or exon 3, or exons 2-3, 2-4, or 2-5. Diverse mutations involving HFE introns and exons discovered in persons with hemochromatosis or their family members cause or probably cause high iron phenotypes. Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. Class I molecules consist of a transmembrane alpha chain and a small chain called the beta-2-microglobulin. The alpha chain contains three extracellular domains, two of which fold together to form the peptide-binding cleft (alpha1 and alpha2), and one which has an Ig fold (alpha3). Peptide binding to class I molecules occurs in the endoplasmic reticulum (ER) and involves both chaperones and dedicated factors to assist in peptide loading. Class I MHC molecules are expressed on most nucleated cells.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 245 RVSPTVKVTQQSPTSMNqvNLTCRAERFYPEDLQLIWLENGNV--SRNDTPKNLTKNTDGTYN-YTSLFLVNSSAHRedv 321
Cdd:cd21021     2 QVPPLVKVTHHVTSSVT--TLRCRALNYYPQNITMKWLKDKQPmdAKEFEPKDVLPNGDGTYQgWITLAVPPGEEQR--- 76

                          90
                  ....*....|....*.
gi 1907136872 322 vFTCQVKHD--QQPAI 335
Cdd:cd21021    77 -YTCQVEHPglDQPLI 91

Immunoglobulin C1-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 250 VKVTQQSPTSMNQVN-LTCRAERFYPEDLQLIWLENGNVSRND-TPKNLTKNTDGTYNYTSLFLVNSSAHREDVVFTCQV 327
Cdd:pfam07654   1 VYVFPPSPEELGKPNtLTCLVTGFYPPDITVTWLKNGQEVTEGvKTTPPSPNSDWTYQLSSYLTVTPSDWESGDEYTCRV 80

                  ..
gi 1907136872 328 KH 329
Cdd:pfam07654  81 EH 82

CH2 domain (second constant Ig domain of the heavy chain) in immunoglobulin mu chain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin constant domain (IgC) of mu heavy chains. This domain is found on the Fc fragment. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda; each is composed of a constant domain and a variable domain. There are five types of heavy chains: alpha, delta, epsilon, gamma, and mu, all consisting of a variable domain (VH) with three (alpha, delta and gamma) or four (epsilon and mu) constant domains (CH1 to CH4). Ig molecules are modular proteins, in which the variable and constant domains have clear, conserved sequence patterns.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1907136872 158 QKVNFTCKSHGFSPRNITLKWFKDGQELHPLETTVNPSGK---NVSYNISSTVRVVLNSMDVNSKVICEVAH 226
Cdd:cd16093    18 RTATFVCLATGFSPKTISFKWLRNGKEVTSSTGAVVEEPKedgKTLYSATSFLTITESEWKSQTEFTCEFKH 89

Second immunoglobulin (Ig)-like domain of nectin-like molecule-3 (Necl-3); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molecule-3 (Necl-3; also known as cell adhesion molecule 2 (CADM2)). 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. 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. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 138 VLAKPSPPEVSGPADRGIPDQKVNFTCKSHGFSPRnITLKWFKDGQELHPLEtTVNPSGKN-VSYNISSTVRVVLNSMDV 216
Cdd:cd05884     1 VLGVPEKPQISGFTSPVMEGDHIQLTCKTSGSKPA-ADIRWFKNDKEVKDVK-YLKAEDANrKTFTVSSSLDFHVDRDDD 78

                          90
                  ....*....|....*..
gi 1907136872 217 NSKVICEVAHITLDRSP 233
Cdd:cd05884    79 GVAITCRVDHESLTATP 95

Class I major histocompatibility complex (MHC) alpha chain, alpha3 immunoglobulin domain; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig) domain of major histocompatibility complex (MHC) class I alpha chain. Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. Class I molecules consist of a transmembrane alpha chain and a small chain called the beta-2-microglobulin. The alpha chain contains three extracellular domains, two of which fold together to form the peptide-binding cleft (alpha1 and alpha2), and one which has an Ig fold (alpha3). Peptide binding to class I molecules occurs in the endoplasmic reticulum (ER) and involves both chaperones and dedicated factors to assist in peptide loading. Class I MHC molecules are expressed on most nucleated cells.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1907136872 135 EVYVLAKPSPPEvsgpadrgipdqKVNFTCKSHGFSPRNITLKWFKDGQELHPLETTVN--PSGkNVSYNISSTVRV 209
Cdd:cd07698     4 KVHVTHHPRSDG------------ESTLRCWALGFYPAEITLTWQRDGEDQTQDMELVEtrPNG-DGTFQKWAAVVV 67

Second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1); member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of nectin-like molcule-1 (Necl-1; also known as cell adhesion molecule3 (CADM3)). 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. Ig domains are likely to participate in ligand binding and recognition.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 139 LAKPSPPEVSGPADRGIPDQKVNFTCKSHGFSPRnITLKWFKDGQELHPLETTVNPSGKNVSYNISSTVRVVLNSMDVNS 218
Cdd:cd07705     1 LGIPQKPQITGYESAFKEKDKAKLRCTSSGSKPA-ANIKWRKGDQELEGAPTSVQEDGNGKTFTVSSSVEFQVTREDDGA 79

                          90
                  ....*....|....*..
gi 1907136872 219 KVICEVAHITL---DRS 232
Cdd:cd07705    80 EITCSVGHESLhdsDRS 96

Immunoglobulin (Ig) variable (V) domain of T-cell receptor (TCR) gamma chain; The members here are composed of the immunoglobulin (Ig) variable (V) domain of the gamma chain of gamma/delta T-cell receptors (TCRs). TCRs mediate antigen recognition by T lymphocytes, and are heterodimers consisting of alpha and beta chains or gamma and delta chains. Each chain contains a variable (V) and a constant (C) region. The majority of T cells contain alpha/beta TCRs, but a small subset contain gamma/delta TCRs. Alpha/beta TCRs recognize antigens as peptide fragments presented by major histocompatibility complex (MHC) molecules. Gamma/delta TCRs recognize intact protein antigens directly without antigen processing and recognize MHC independently of the bound peptide. Gamma/delta T cells can also be stimulated by non-peptide antigens such as small phosphate- or amine-containing compounds. The variable domain of gamma/delta TCRs is responsible for antigen recognition and is located at the N-terminus of the receptor. Members of this group contain the standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  29 VTQPEKSVSVAAGDSTVLNCTLTSL-LPVGPIRWYR---GVGPSRLLIYSfageYVPRIRNVSDTTK--------RNNMD 96
Cdd:cd04982     1 LEQPQLSITREESKSVTISCKVSGIdFSTTYIHWYRqkpGQALERLLYVS----STSAVRKDSGKTKnkfearkdVGKST 76

                          90       100
                  ....*....|....*....|....*.
gi 1907136872  97 FSIRISNVTPADAGIYYCVKFQKGSS 122
Cdd:cd04982    77 STLTITNLEKEDSATYYCAYWESGSG 102

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) I-E; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) I-E. Three genetically distinct isotypes of class II MHC molecules are found in humans (HLA-DR, HLA-DQ, and HLA-DP), and two in mice (I-E and I-A). I-A and I-E molecules have the same basic features insofar as peptide loading and presentation, although each interacts with distinctly different sets of peptides. They also differ in that there is a relatively high incidence of deletion of the I-E gene in both inbred strains of mice as well as wild mice and the lack of the reverse situation i.e. the deletion of I-A genes. A detailed structural understanding of the similarities and differences between I-A and the paralogous I-E could help illuminate the respective roles these molecules play in peptide presentation and T cell activation. Mouse I-Ag7 has a genetic susceptibility to autoimmune diabetes due to its small, uncharged amino acid residue at position 57 of their beta chain which results in the absence of a salt bridge between beta 57 and Arg alpha 76, which is adjacent to the P9 pocket of the peptide-binding groove. MHC class II molecules play a key role in the initiation of the antigen-specific immune reponse. These molecules have been shown to be expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice. The expression of these molecules has been shown to be induced in nonprofessional APCs such as keratinocyctes, and they are expressed on the surface of activated human T cells and on T cells from other species. The MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes. These peptides derive mostly from proteolytic processing via the endocytic pathway, of antigens internalized by the APC. These peptides bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain had two globular domains (N- and C-terminal), and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 245 RVSPTVKV--TQQSPTSMNQVnLTCRAERFYPEDLQLIWLENGNVSRND-TPKNLTKNTDGTYNytSLFLVNSSAHREDv 321
Cdd:cd20998     4 RVEPTVTVypTKTQPLEHHNL-LVCSVSDFYPGNIEVRWFRNGKEEKTGiVSTGLVRNGDWTFQ--TLVMLETVPQSGE- 79

                          90       100
                  ....*....|....*....|
gi 1907136872 322 VFTCQVKHdqqPAITRNHTV 341
Cdd:cd20998    80 VYTCQVEH---PSLTDPVTV 96

Immunoglobulin (Ig) lambda light chain variable (V) domain; The members here are composed of the immunoglobulin (Ig) light chain, lambda type, variable (V) domain. The basic structure of Ig molecules is a tetramer of two light chains and two heavy chains linked by disulfide bonds. There are two types of light chains: kappa and lambda, each composed of a constant domain (CL) and a variable domain (VL). There are five types of heavy chains (alpha, gamma, delta, epsilon, and mu), which determines the type of immunoglobulin formed: IgA, IgG, IgD, IgE, and IgM, respectively. In higher vertebrates, there are two types of light chain, designated kappa and lambda, which seem to be functionally identical, and can associate with any of the heavy chains. Members of this group contain standard Ig superfamily V-set AGFCC'C"/DEB domain topology.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  29 VTQPEkSVSVAAGDSTVLNCTLTSLLPVGP-IRWYRGVGPS--RLLIY--SFAGEYVP-RIRNVSDTTKRnnmdfSIRIS 102
Cdd:cd04984     2 LTQPS-SLSVSPGETVTITCTGSSGNISGNyVNWYQQKPGSapRYLIYedKHRPSGIPdRFSGSKSGNTA-----SLTIS 75

                          90       100       110
                  ....*....|....*....|....*....|....*.
gi 1907136872 103 NVTPADAGIYYCVKFQKGSsepdteIQSGGGTEVYV 138
Cdd:cd04984    76 GAQTEDEADYYCQVWDSNS------YVFGGGTKLTV 105

Immunoglobulin domain of Cluster of Differentiation (CD) 1; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin domain of Cluster of Differentiation (CD) 1. CD1 family of transmembrane glycoproteins, are structurally related to the major histocompatibility complex (MHC) proteins and form heterodimers with beta-2-microglobulin. They mediate the presentation of primarily lipid and glycolipid antigens of self or microbial origin to T cells. The human genome contains five CD1 family genes (CD1a, CD1b, CD1c, CD1d, and CD1e) organized in a cluster on chromosome 1. The CD1 family members are thought to differ in their cellular localization and specificity for particular lipid ligands. CD1a localizes to the plasma membrane and to recycling vesicles of the early endocytic system. Alternative splicing results in multiple transcript variants. Immunoglobulin (Ig) domain of major histocompatibility complex (MHC) class I alpha chain. Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. Class I molecules consist of a transmembrane alpha chain and a small chain called the beta-2-microglobulin. The alpha chain contains three extracellular domains, two of which fold together to form the peptide-binding cleft (alpha1 and alpha2), and one which has an Ig fold (alpha3). Peptide binding to class I molecules occurs in the endoplasmic reticulum (ER) and involves both chaperones and dedicated factors to assist in peptide loading. Class I MHC molecules are expressed on most nucleated cells. C1-set Ig domains have one beta sheet that is formed by strands A, B, E, and D and the other strands by G, F, C, and C'.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 135 EVYVLAKPSPPevsgpadrgipDQKVNFTCKSHGFSPRNITLKWFKDGQELHP-LETT-VNPSGkNVSYNISSTVRVVLN 212
Cdd:cd21029     4 RVRLSSRPSPG-----------DGHLQLSCHVTGFYPRPIEVTWLRDGQEQMDgTQSGgILPNH-DGTYQLRKTLDIAPG 71

                          90       100
                  ....*....|....*....|
gi 1907136872 213 SMDvnsKVICEVAHITLDRS 232
Cdd:cd21029    72 EGA---GYSCRVDHSSLKQD 88

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) DQ and I-A; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of human histocompatibility antigen (HLA) DQ and mouse I-A. Three genetically distinct isotypes of class II MHC molecules are found in humans (HLA-DR, HLA-DQ, and HLA-DP), and two in mice (I-E and I-A). I-A and I-E have the same basic features insofar as peptide loading and presentation, they differ in that each interacts with distinctly different sets of peptides, and in the incidence of deletion of their genes. A structural understanding of the similarities and differences between I-A and I-E may help with understanding their roles in peptide presentation and T cell activation. Mouse I-Ag7 has a genetic susceptibility to autoimmune diabetes due to its small, uncharged amino acid residue at position 57 of their beta chain which results in the absence of a salt bridge between beta 57 and Arg alpha 76, which is adjacent to the P9 pocket of the peptide-binding groove. Human HLA-DR, -DQ, and -DP are about 70% similar to each other. HLA-DQ (DQ) is a cell surface receptor protein found on antigen presenting cells. It is an alphabeta heterodimer of type MHC class II. The alpha and beta chains are encoded by two loci, HLA-DQA1 and HLA-DQB1, that are adjacent to each other on chromosome band 6p21.3. A person often produces two alpha-chain and two beta chain variants and thus 4 isoforms of DQ. HLA-DQ is involved in the autoimmune diseases celiac disease and diabetes mellitus type. DQ is one of several antigens involved in rejection of organ transplants. DQ2 is encoded by the HLA-DQB1*02 allele group. DQ6 is encoded by the HLA-DQB1*06 allele group. DQ2 beta-chains combine with alpha-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. These isoforms, nicknamed DQ2.2 and DQ2.5, are also encoded by the DQA1*0201 and DQA1*0501 genes, respectively. DQ6 beta-chains combine with alpha-chains, encoded by genetically linked HLA-DQA1 alleles, to form the cis-haplotype isoforms. For DQ6, however, cis-isoform pairing only occurs with DQ1 alpha-chains. There are many haplotypes of DQ6. Susceptibility to Leptospirosis infection was found associated with undifferentiated DQ6. DQ8 is determined by the antibody recognition of beta8 and this generally detects the gene product of DQB1*0302. DQ8 is commonly linked to autoimmune disease in the human population. DQ8 is the second most predominant isoform linked to celiac disease and the DQ most linked to Type 1 diabetes. DQ8 increases the risk for rheumatoid arthritis and is linked to the primary risk locus for RA, HLA-DR4. DR4 also plays an important role in Type 1 diabetes. DQ8 is a split antigen of the DQ3 broad antigen. MHC class II molecules play a key role in the initiation of the antigen-specific immune response. They are expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice, and induced in nonprofessional APCs, such as keratinocyctes; they are expressed on the surface of activated human T cells and on T cells from other species. MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes; these peptides derive mostly from proteolytic processing via the endocytic pathway, of antigens internalized by the APC, and bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain had two globular domains (N- and C-terminal), and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 245 RVSPTVKVTQQSPTSMNQVN-LTCRAERFYPEDLQLIWLEN------GNVSrndTPknLTKNTDGTYNYtsLFLVNSSAH 317
Cdd:cd21001     1 RVEPTVTISPSRTEALNHHNlLVCSVTDFYPGQIKVRWFRNdqeetaGVVS---TP--LIRNGDWTFQI--LVMLEMTPQ 73

                          90
                  ....*....|..
gi 1907136872 318 REDvVFTCQVKH 329
Cdd:cd21001    74 RGD-VYTCHVEH 84

Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) DR; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class II major histocompatibility complex (MHC) beta chain immunoglobulin domain of histocompatibility antigen (HLA) DR. HLA-DR is an MHC class II cell surface receptor encoded by the human leukocyte antigen complex on chromosome 6 region 6p21.31. HLA-DR is also involved in several autoimmune conditions, disease susceptibility, and disease resistance including seronegative-rheumatoid arthritis, penicillamine-induced myasthenia, schizophrenia, Goodpasture syndrome, systemic lupus erythematosus, Alzheimers, tuberculoid leprosy, and Hashimoto's thyroiditis. HLA-DR molecules are upregulated in response to signaling. HLA-DR is an alphabeta heterodimer cell surface receptor, each subunit of which contains two extracellular domains, a membrane-spanning domain, and a cytoplasmic tail. Both alpha and beta chains are anchored in the membrane. The DR beta chain is encoded by 4 loci, however no more than 3 functional loci are present in a single individual, and no more than two on a single chromosome. Sometimes an individual may only possess 2 copies of the same locus, DRB1*. The HLA-DRB1 locus is ubiquitous and encodes a very large number of functionally variable gene products (HLA-DR1 to HLA-DR17). The HLA-DRB3 locus encodes the HLA-DR52 specificity, is moderately variable and is variably associated with certain HLA-DRB1 types. The HLA-DRB4 locus encodes the HLA-DR53 specificity, has some variation, and is associated with certain HLA-DRB1 types. The HLA-DRB5 locus encodes the HLA-DR51 specificity, which is typically invariable, and is linked to the HLA-DR2 types. Three genetically distinct isotypes of class II MHC molecules are found in humans (HLA-DR, HLA-DQ, and HLA-DP), and two in mice (I-E and I-A). MHC class II molecules play a key role in the initiation of the antigen-specific immune reponse. These molecules have been shown to be expressed constitutively on the cell surface of professional antigen-presenting cells (APCs), including B-lymphocytes, monocytes, and macrophages in both humans and mice. The expression of these molecules has been shown to be induced in nonprofessional APCs such as keratinocyctes, and they are expressed on the surface of activated human T cells and on T cells from other species. The MHC II molecules present antigenic peptides to CD4(+) T-lymphocytes. These peptides derive mostly from proteolytic processing via the endocytic pathway, of antigens internalized by the APC. These peptides bind to the MHC class II molecules in the endosome before they are transported to the cell surface. MHC class II molecules are heterodimers, comprised of two similarly-sized membrane-spanning chains, alpha and beta. Each chain had two globular domains (N- and C-terminal), and a membrane-anchoring transmembrane segment. The two chains form a compact four-domain structure. The peptide-binding site is a cleft in the structure.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 245 RVSPTVKVTQQSPTSMNQVNL-TCRAERFYPEDLQLIWLENGNVSRNDT-PKNLTKNTDGTYNYTSLFlvnSSAHREDVV 322
Cdd:cd21000     1 RVEPKVTVYPAKTQPLQHHNLlVCSVNGFYPGSIEVRWFRNGQEEKAGVvSTGLIQNGDWTFQTLVML---ETVPRSGEV 77

                          90
                  ....*....|....*....
gi 1907136872 323 FTCQVKHdqqPAITRNHTV 341
Cdd:cd21000    78 YTCQVEH---PSVTSPLTV 93

Signal-regulatory protein (SIRP) immunoglobulin-like domain 2; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in Signal-Regulatory Protein (SIRP), domain 2 (C1 repeat 1). The SIRPs belong to the "paired receptors" class of membrane proteins that comprise several genes coding for proteins with similar extracellular regions, but very different transmembrane/cytoplasmic regions with different (activating or inhibitory) signaling potentials. They are commonly on NK cells, but are also on many myeloid cells. Their extracellular region contains three Immunoglobulin superfamily domains, a single V-set and two C1-set IgSF domains. Their cytoplasmic tails contain either ITIMs or transmembrane regions that have positively charged residues that allow an association with adaptor proteins, such as DAP12/KARAP, containing ITAMs. There are 3 distinct SIRP members: alpha, beta, and gamma. SIRP alpha (also known as CD172a or SRC homology 2 domain-containing protein tyrosine phosphatase substrate 1/Shps-1) is a membrane receptor that interacts with a ligand CD47 expressed on many cells and gives an inhibitory signal through immunoreceptor tyrosine-based inhibition motifs in the cytoplasmic region that interact with phosphatases SHP-1 and SHP-2. SIRP beta has a short cytoplasmic region and associates with a transmembrane adapter protein DAP12 containing immunoreceptor tyrosine-based activation motifs to give an activating signal. SIRP gamma contains a very short cytoplasmic region lacking obvious signaling motifs, but also binds CD47, but with much less affinity.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 263 VNLTCRAERFYPEDLQLIWLENGNVSRNDTPKNLTKNTDGTYNYTSLFLVnsSAHREDVV--FTCQVKHD 330
Cdd:cd05772    20 VSFTCKSHGFSPRDITLKWFKNGNELSALQTTVFPEGDSVSYSVSSTVQV--VLTKDDVHsqLTCEVAHV 87

Class Ib major histocompatibility complex (MHC) immunoglobulin domain of HLA-Cw3 and HLA-Cw4; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class Ib major histocompatibility complex (MHC) immunoglobulin domain of HLA-Cw3 and HLA-Cw4. HLA-C belongs to the MHC class I heavy chain receptors. The C receptor is a heterodimer consisting of a HLA-C mature gene product and beta-2-microglobulin. The mature C chain is anchored in the membrane. MHC Class I molecules, like HLA-C, are expressed in nearly all cells, and present small peptides to the immune system which surveys for non-self peptides. HLA-C is a locus on chromosome 6, which encodes for a large number of HLA-C alleles that are Class-I MHC receptors. Class Ib histocompatibility leukocyte antigens (HLA)-Cw3 and (HLA)-Cw4 are ligands for the natural killer (NK) cell inhibitory receptors KIR2DL2 and KIR2DL1, respectively. HLA-Cw3 and related alleles (HLA-Cw1, -Cw7, and -Cw8) contain Ser77 and Asn80 and interact with KIR that are reactive with the GL183 antibody Class I MHC proteins bind antigenic peptide fragments and present them to CD8+ T lymphocytes. HLA-Cw4 and related alleles (HLA-Cw2, -Cw5, and -Cw6) have Asn77 and Lys80 and are recognized by KIR reactive with the EB6 15 or HP-3E4 16 antibody. Members of the IgC family are components of immunoglobulin, T-cell receptors, CD1 cell surface glycoproteins, secretory glycoproteins A/C, and major histocompatibility complex (MHC) class I/II molecules. In immunoglobulins, each chain is composed of one variable domain (IgV) and one or more IgC domains. These names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. The IgV domain is responsible for antigen binding, and the IgC domain is involved in oligomerization and molecular interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 248 PTVKVTQQsPTSMNQVNLTCRAERFYPEDLQLIWLENGNVSRNDTPKNLTKNT-DGTYNYTSLFLVNSSahrEDVVFTCQ 326
Cdd:cd21025     6 PKTHVTHH-PVSDHEATLRCWALGFYPAEITLTWQWDGEDQTQDTELVETRPAgDGTFQKWAAVVVPSG---EEQRYTCH 81

                  ....*..
gi 1907136872 327 VKHDQQP 333
Cdd:cd21025    82 VQHEGLP 88

Class Ia major histocompatibility complex (MHC) immunoglobulin domain of MIC-A and MIC-B; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the Class Ia major histocompatibility complex (MHC) immunoglobulin domain of MIC-A and MIC-B. MIC-A and MIC-B are homologs that serve as stress-inducible antigens on epithelial and epithelially derived cells. Both serve as ligands for the widely expressed activating immunoreceptor NKG2D, a C-type lectin-like activating immunoreceptor. MIC-B is very similar in structure to MIC-A and likely interacts with NKG2D in an analogous manner. The interdomain flexibility observed in the MIC-A structures, a feature unique to MIC proteins among MHC class I proteins and homologs, is also displayed by MIC-B, with an interdomain relationship intermediate between the two examples of MIC-A structures. Mapping sequence variations onto the structures of MIC-A and MIC-B reveals patterns completely distinct from those displayed by classical MHC class I proteins, with a number of substitutions falling on positions likely to affect interactions with NKG2D, but with other positions lying distant from the NKG2D binding sites or buried within the core of the proteins. Members of the IgC family are components of immunoglobulin, T-cell receptors, CD1 cell surface glycoproteins, secretory glycoproteins A/C, and major histocompatibility complex (MHC) class I/II molecules. In immunoglobulins, each chain is composed of one variable domain (IgV) and one or more IgC domains. These names reflect the fact that the variability in sequences is higher in the variable domain than in the constant domain. The IgV domain is responsible for antigen binding and the IgC domain is involved in oligomerization and molecular interactions.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872 246 VSPTVKVTQqSPTSMNQVNLTCRAERFYPEDLQLIWLENGNVSRNDTPK--NLTKNTDGTYNytsLFLVNSSAHREDVVF 323
Cdd:cd21017     3 VPPMVNVTR-SEASEGNITVTCRASGFYPWNITLSWRQDGVSLSHDTQQwgDVLPDGNGTYQ---TWVATRICQGEEQRF 78

                  ....*.
gi 1907136872 324 TCQVKH 329
Cdd:cd21017    79 TCYMEH 84

Immunoglobulin (Ig)-like domain of myelin oligodendrocyte glycoprotein (MOG); The members here are composed of the immunoglobulin (Ig)-like domain of myelin oligodendrocyte glycoprotein (MOG). MOG, a minor component of the myelin sheath, is an important CNS-specific autoantigen, linked to the pathogenesis of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). It is a transmembrane protein having an extracellular Ig domain. MOG is expressed in the CNS on the outermost lamellae of the myelin sheath, and on the surface of oligodendrocytes, and may participate in the completion, compaction, and/or maintenance of myelin. This group also includes butyrophilin (BTN). BTN is the most abundant protein in bovine milk-fat globule membrane (MFGM).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  28 KVTQPEKSVSVAAGDSTVLNCTLTsllpvgP--------IRWYRGvGPSRL-LIY----SFAGEYVPRIRN----VSDTT 90
Cdd:cd05713     2 SVIGPTEPILALVGEDAELPCHLS------PkmsaehmeVRWFRS-QFSPVvHLYrdgqDQEEEQMPEYRGrtelLKDAI 74

                          90       100       110
                  ....*....|....*....|....*....|..
gi 1907136872  91 KRNNMdfSIRISNVTPADAGIYYCVkFQKGSS 122
Cdd:cd05713    75 AEGSV--ALRIHNVRPSDEGQYTCF-FRSGSF 103

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1907136872  28 KVTQPEKSVSVAAGDSTVLNCTLTSLlPVGPIRWYRG---VGPSRLLiysfageyvpRIRNVSDTTkrnnmdfSIRISNV 104
Cdd:pfam07679   2 KFTQKPKDVEVQEGESARFTCTVTGT-PDPEVSWFKDgqpLRSSDRF----------KVTYEGGTY-------TLTISNV 63

                          90
                  ....*....|.
gi 1907136872 105 TPADAGIYYCV 115
Cdd:pfam07679  64 QPDDSGKYTCV 74