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 240255629  35 FTVIGSQRPILATLGGNVELNCQLSPPQQAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVI 114
Cdd:cd05713    1 FSVIGPTEPILALVGEDAELPCHLSPKMSAEHMEVRWFRSQFSPVVHLYRDGQDQEEEQMPEYRGRTELLKDAIAEGSVA 80

                         90       100       110
                 ....*....|....*....|....*....|....
gi 240255629 115 LRILNVTVDDGGAYHCVFKDGEFYEEHITEVKVT 148
Cdd:cd05713   81 LRIHNVRPSDEGQYTCFFRSGSFYEEATLELKVA 114

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 240255629  35 FTVIGSQRPILATLGGNVELNCQLSPPQQAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVI 114
Cdd:cd05713    1 FSVIGPTEPILALVGEDAELPCHLSPKMSAEHMEVRWFRSQFSPVVHLYRDGQDQEEEQMPEYRGRTELLKDAIAEGSVA 80

                         90       100       110
                 ....*....|....*....|....*....|....
gi 240255629 115 LRILNVTVDDGGAYHCVFKDGEFYEEHITEVKVT 148
Cdd:cd05713   81 LRIHNVRPSDEGQYTCFFRSGSFYEEATLELKVA 114

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629    41 QRPILATLGGNVELNCQLSPPQQAQhmeIRWFRNrytqpvhlyrngknlhGETMSKYVERTELLtdaFNEGKVILRILNV 120
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPE---VTWYKQ----------------GGKLLAESGRFSVS---RSGSTSTLTISNV 58

                           90       100
                   ....*....|....*....|....*..
gi 240255629   121 TVDDGGAYHCVFKDGEFYEEHITEVKV 147
Cdd:smart00410  59 TPEDSGTYTCAATNSSGSASSGTTLTV 85

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 240255629  35 FTVIGSQRPILATLGGNVELNCQLSPPQQAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVI 114
Cdd:cd05713    1 FSVIGPTEPILALVGEDAELPCHLSPKMSAEHMEVRWFRSQFSPVVHLYRDGQDQEEEQMPEYRGRTELLKDAIAEGSVA 80

                         90       100       110
                 ....*....|....*....|....*....|....
gi 240255629 115 LRILNVTVDDGGAYHCVFKDGEFYEEHITEVKVT 148
Cdd:cd05713   81 LRIHNVRPSDEGQYTCFFRSGSFYEEATLELKVA 114

Immunoglobulin Variable (IgV) domain of B7-H4; The members here are composed of the immunoglobulin variable (IgV) domain of B7-H4 (also known as B7-S1, B7x, or Vtcn1). B7-H4 is one of the B7 family of immune-regulatory ligands that act as negative regulators of T cell function; it contains one IgV domain and one IgC domain. The B7-family consists of structurally related cell-surface protein ligands, which bind to receptors on lymphocytes that regulate immune responses. The binding of B7-H4 to unidentified receptors results in the inhibition of TCR-mediated T cell proliferation, cell-cycle progression and IL-2 production. As a co-inhibitory molecule, B7-H4 is widely expressed in tumor tissues and its expression is significantly associated with poor prognosis in human cancers such as glioma, pancreatic cancer, oral squamous cell carcinoma, renal cell carcinoma, and lung cancer.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  45 LATLGGNVELNCQLSPPQQAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVILRILNVTVDD 124
Cdd:cd20984    8 AGNIGEDGILSCTFTPDIKLSDIVIQWLKEGDSGLVHEFKEGKDELSRQSPMFRGRTSLFADQVHVGNASLRLKNVQLTD 87

                 ....*..
gi 240255629 125 GGAYHCV 131
Cdd:cd20984   88 AGTYLCI 94

Immunoglobulin Variable (IgV) domain in HERV-H LTR-associating 2 (HHLA2); The members here are composed of the immunoglobulin variable (IgV) region in HERV-H LTR-associating 2 (HHLA2; also known as B7-H7/B7 homolog 7). HHLA2 is a member of the B7 family of immune regulatory proteins. Mature human HHLA2 consists of an extracellular domain (ECD) with three immunoglobulin-like domains, a transmembrane segment, and a cytoplasmic domain. HHLA2 is widely expressed in human cancers including non-small cell lung carcinoma (NSCLS), triple negative breast cancer (TNBC), and melanoma, but has limited expression on normal tissues. Interestingly, unlike other members of B7 family, HHLA2 is not expressed in mice or rats. HHLA2 functions as a T cell coinhibitory molecules as it inhibits the proliferation of activated CD4(+) and CD8(+) T cells and their cytokine production. Furthermore, HHLA2 is constitutively expressed on the surface of human monocytes and is induced on B cells after stimulation, however it is not inducible on T cells.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  39 GSQRPILATLGGNVELNCQLSPpqqAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVILRIL 118
Cdd:cd16091    2 VSEVIVVCLLSEDCILPCSFTP---GSEVVIHWYKQDSDIKVHSYYYGKDQLESQDQRYRNRTSLFKDQISNGNASLLLR 78

                         90       100
                 ....*....|....*....|....*....
gi 240255629 119 NVTVDDGGAYHCVFKDGEFYEEHITEVKV 147
Cdd:cd16091   79 RVQLQDEGRYKCYTSTIIGNQESFVNLKV 107

Immunoglobulin Variable (IgV) domain of B7-H3, a member of the B7 family of immune checkpoint molecules; The members here are composed of the immunoglobulin variable (IgV) domain of B7-H3 also known as CD276), a member of the B7 family of immune checkpoint molecules. B7-H3 is an important immune checkpoint member of the B7 family and shares homology with other B7 ligands such as programmed death ligand 1 (PD-L1). The B7 family molecules interact with CD28 on T-cells to provide co-stimulatory signals that regulate T-cell activation and T-helper cell differentiation. Although B7-H3 has been shown to have both co-stimulatory and co-inhibitory effects on T-cell responses, the most current studies describe B7-H3 as a T cell inhibitor that promotes tumor aggressiveness and proliferation. Moreover, B7-H3 is highly overexpressed on a wide range of human solid cancers and promotes tumor growth, metastasis, and drug resistance. Thus, B7-H3 expression in tumors often correlates with both negative prognosis and poor clinical outcome in cancer patients. B7-H3 protein contains a predicted signal peptide, V- and C-like Ig domains (IgV and IgC), a transmembrane region, and an intracellular tail.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  40 SQRPILATLGGNVELNCQLSPPQ--QAQHMEIRWFRNRYTQPVHLYRNGKNLHGETMSKYVERTELLTDAFNEGKVILRI 117
Cdd:cd20934    3 PEDPVVALVGTDATLRCSFSPEPgfSLAQLSVFWQLTDTKQLVHSFTESQDQGRDQGSAYANRTALFPDLLAQGNASLRL 82

                         90
                 ....*....|...
gi 240255629 118 LNVTVDDGGAYHC 130
Cdd:cd20934   83 QRVRVADEGSYTC 95

First immunoglobulin variable (IgV) domain of poliovirus receptor (PVR, also known as CD155 and necl-5), and similar domains; The members here are composed of the first immunoglobulin (Ig) domain of poliovirus receptor (PVR, also known as CD155 and nectin-like protein 5 (necl-5)). Poliovirus (PV) binds to its cellular receptor (PVR/CD155) to initiate infection. CD155 is a membrane-anchored, single-span glycoprotein; its extracellular region has three Ig-like domains. There are four different isotypes of CD155 (referred to as alpha, beta, gamma, and delta), that result from alternate splicing of the CD155 mRNA, and have identical extracellular domains. CD155-beta and CD155-gamma are secreted; CD155-alpha and CD155-delta are membrane-bound and function as PV receptors. The virus recognition site is contained in the amino-terminal domain, D1. Having the virus attachment site on the receptor distal from the plasma membrane may be important for successful initiation of infection of cells by the virus. CD155 binds in the poliovirus "canyon" with a footprint similar to that of the intercellular adhesion molecule-1 receptor on human rhinoviruses. This group also includes the first Ig-like domain of nectin-1 (also known as poliovirus receptor related protein(PVRL)1; CD111), nectin-3 (also known as PVRL 3), nectin-4 (also known as PVRL4; LNIR receptor)and DNAX accessory molecule 1 (DNAM-1; CD226).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  46 ATLGGNVELNCQLSPPQQAQHMEIRWFR--NRYTQPVHLYRNGKNLHgeTMSKYVERTELLTDAFNEGKVILRILNVTVD 123
Cdd:cd05718   11 GFLGGSVTLPCSLTSPGTTKITQVTWMKigAGSSQNVAVFHPQYGPS--VPNPYAERVEFLAARLGLRNATLRIRNLRVE 88

                 ....*....
gi 240255629 124 DGGAYHCVF 132
Cdd:cd05718   89 DEGNYICEF 97

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 240255629  37 VIGSQRPILATLGGNVELNCQLSppQQAQHMEIRWFRNRY-TQPVHLYR---NGKNLHGETMSKYVERTELLTDAFnegk 112
Cdd:cd00099    1 VTQSPRSLSVQEGESVTLSCEVS--SSFSSTYIYWYRQKPgQGPEFLIYlssSKGKTKGGVPGRFSGSRDGTSSFS---- 74

                         90
                 ....*....|....*....
gi 240255629 113 viLRILNVTVDDGGAYHCV 131
Cdd:cd00099   75 --LTISNLQPEDSGTYYCA 91

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629   36 TVIGSQRPILATLGGNVELNCQLSPPQQAqhmEIRWfrnrytqpvhlYRNGKNLHGETMSKYVertelltdaFNEGKVIL 115
Cdd:pfam13927   3 VITVSPSSVTVREGETVTLTCEATGSPPP---TITW-----------YKNGEPISSGSTRSRS---------LSGSNSTL 59

                          90
                  ....*....|....*.
gi 240255629  116 RILNVTVDDGGAYHCV 131
Cdd:pfam13927  60 TISNVTRSDAGTYTCV 75

First immunoglobulin variable (IgV) domain of nectin-2, nectin-like protein 5, and similar domains; The members here are composed of the second immunoglobulin (Ig) domain of nectin-2 (also known as poliovirus receptor related protein 2 or Cluster of Differentiation 112 (CD112)), nectin-like protein 5 (CD155), and similar proteins. Nectins and Nectin-like molecules are a family of Ca(2+)-independent immunoglobulin-like transmembrane glycoproteins belonging to the class of adhesion receptors, consisting of nine members (nectins 1 through 4 and nectin-like proteins 1 through 5). Nectins are synaptic cell adhesion molecules (CAMs) which facilitate adhesion and signaling at various intracellular junctions. Nectins form homophilic cis-dimers, followed by homophilic and heterophilic trans-dimers involved in cell-cell adhesion. Nectin-2 and nectin-3 localize at Sertoli-spermatid junctions where they form heterophilic trans-interactions between the cells that are essential for the formation and maintenance of the junctions and for spermatid development. CD155 is the fifth member in the nectin-like molecule family, and functions as the receptor of poliovirus; therefore, CD155 is also referred to as Necl-5, or PVR. In contrast to all other family members, CD155 lacks self-adhesion capacity, yet it shares with nectins the feature to interact with other nectins. For instance, CD155 heterophilically trans-interacts with nectin-3, thereby contributing significantly to the establishment of adherens junctions between epithelial cells. This group belongs to the Constant 1 (C1)-set of IgSF domains, which has one beta-sheet that is formed by strands A-B-E-D and the other strands by G-F-C-C'.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  48 LGGNVELNCQLSPPQQAQHM-EIRWFRNRYTQPVHLY--RNGKNLHGETMSKYVeRTELLTDAFNegkVILRILNVTVDD 124
Cdd:cd20989   13 LGGSVTLPCHLLPPNMVTHVsQVTWQRHDEHGSVAVFhpKQGPSFPESERLSFV-AARLGAELRN---ASLAMFGLRVED 88

                 ....*...
gi 240255629 125 GGAYHCVF 132
Cdd:cd20989   89 EGNYTCEF 96

N-terminal immunoglobulin (Ig)-like domain of T-cell surface antigen CD2, and similar domains; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain (or domain 1) of T-cell surface antigen Clusters of Differentiation (CD) 2 and similar proteins. CD2 is a T-cell specific surface glycoprotein and is critically important for mediating adhesion between T cells and antigen-presenting cells or between cytolytic T cells and target cells. CD2 is located on chromosome 1 at 1p13 in humans and on chromosome 3 in mice. CD2 contains an extracellular domain with two or Ig-like domains, a single transmembrane segment, and a cytoplasmic region rich in proline and basic residues.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 240255629  40 SQRPILATLGGNVELNcqlSPPQQAQHMEIRWFRNRyTQPVHLYRNGKNlhgETMSKYVERTELLTDAFNegkviLRILN 119
Cdd:cd05775    1 SSGEVYGALGGNVTLT---ISSLQDDIDEIKWKKTK-DKIVEWENNIGP---TYFGSFKDRVLLDKESGS-----LTIKN 68

                         90
                 ....*....|
gi 240255629 120 VTVDDGGAYH 129
Cdd:cd05775   69 LTKEDSGTYE 78