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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 85719303 146 QPFLQVTN-TTVKELDSVTLTCLSNDIGANIQWLFNSQSLQLTERMTLSQNNSILRIDPIKREDAGEYQCEISNPVSVRR 224
Cdd:cd05740   1 KPFISSNNsNPVEDKDAVTLTCEPETQNTSYLWWFNGQSLPVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVSANR 80

                ....*....
gi 85719303 225 SNSIKLDII 233
Cdd:cd05740  81 SDPVTLDVI 89

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

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 85719303 146 QPFLQVTN-TTVKELDSVTLTCLSNDIGANIQWLFNSQSLQLTERMTLSQNNSILRIDPIKREDAGEYQCEISNPVSVRR 224
Cdd:cd05740   1 KPFISSNNsNPVEDKDAVTLTCEPETQNTSYLWWFNGQSLPVTPRLTLSNGNRTLTLLNVTREDAGAYQCEISNPVSANR 80

                ....*....
gi 85719303 225 SNSIKLDII 233
Cdd:cd05740  81 SDPVTLDVI 89

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 85719303    153 NTTVKELDSVTLTC-LSNDIGANIQWLFNSQS-LQLTERMTLSQN--NSILRIDPIKREDAGEYQCEISNPVSVRRSN 226
Cdd:smart00410   3 SVTVKEGESVTLSCeASGSPPPEVTWYKQGGKlLAESGRFSVSRSgsTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

Transmembrane domain of Ephrin Receptor A1 Protein Tyrosine Kinase; Ephrin receptors (EphRs) comprise the largest subfamily of receptor PTKs, and are classified into two classes (EphA and EphB), corresponding to binding preferences for either GPI-anchored ephrin-A ligands or transmembrane ephrin-B ligands. Vertebrates have ten EphA and six EphB receptors, which display promiscuous ligand interactions within each class. EphA1 has been associated with late-onset Alzheimer's disease and certain cancers such as colorectal and gastric carcinomas. EphRs contain an ephrin binding domain and two fibronectin repeats extracellularly, a single-span transmembrane (TM) domain, and a cytoplasmic tyr kinase domain. Binding of the ephrin ligand to EphR requires cell-cell contact since both are anchored to the plasma membrane. This allows ephrin/EphR dimers to form, leading to the activation of the intracellular tyr kinase domain. The resulting downstream signals occur bidirectionally in both EphR-expressing cells (forward signaling) and ephrin-expressing cells (reverse signaling). The main effect of ephrin/EphR interaction is cell-cell repulsion or adhesion. Ephrin/EphR signaling is important in neural development and plasticity, cell morphogenesis and proliferation, cell-fate determination, embryonic development, tissue patterning, and angiogenesis. The TM domain mediates dimerization.

                        10        20        30
                ....*....|....*....|....*....|....*..
gi 85719303 236 PTQGGLSDGAIAGIVIGVVAGVALIAGLaYFLYSRKS 272
Cdd:cd12841   3 PVSRGLTGGEIVAIIFGLLLGVALLLGI-LVFRSRRA 38

Immunoglobulin (Ig)-like domain of carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain in carcinoembryonic antigen (CEA) related cell adhesion molecule (CEACAM) and related 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. This group represents the CEACAM subfamily. CEACAM1 has many important cellular functions: it is a cell adhesion molecule and a signaling molecule that regulates the growth of tumor cells, an angiogenic factor, and a receptor for bacterial and viral pathogens, including mouse hepatitis virus (MHV). In mice, four isoforms of CEACAM1 generated by alternative splicing have either two (D1, D4) or four (D1-D4) Ig-like domains on the cell surface. This family corresponds to the D1 Ig-like domain. Also belonging to this group is the N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family, CD84-like family. The SLAM family is a group of immune-cell specific receptors that can regulate both adaptive and innate immune responses. SLAM family proteins are organized as an extracellular domain with having two or four Ig-like domains, a single transmembrane segment, and a cytoplasmic region having Tyr-based motifs. The extracellular domain is organized as a membrane-distal Ig variable (IgV) domain that is responsible for ligand recognition and a membrane-proximal truncated Ig constant-2 (IgC2) domain.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 85719303  43 PQVAEDNNVLLLVHNLPLALGAFAWYKGNTTAIDKEIARFVPNSNMNFTGQAYSGREIIYSNGSLLFQMITMKDMGVYTL 122
Cdd:cd05741   5 FYGAEGKNVLLLVPNLQTPLKSVSWYKGKQVSRNDEIAEYENSSDEFRAGSAFSGREYIYTNGSLLIQNITLSDTGFYTL 84

                        90
                ....*....|....*...
gi 85719303 123 DMTDENYRRTQATVRFHV 140
Cdd:cd05741  85 ESTNIGGKTESATFQLHV 102

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 85719303    38 IEAVPPQVAEDNNVLLLVHNLPL---ALGAFAWYKGNT-TAIDKEIARFVPNSNMNFTGQAYSGRE-IIYSNGSLLFQMI 112
Cdd:pfam07686   1 QTPREVTVALGGSVTLPCTYSSSmseASTSVYWYRQPPgKGPTFLIAYYSNGSEEGVKKGRFSGRGdPSNGDGSLTIQNL 80

                          90       100
                  ....*....|....*....|....*....
gi 85719303   113 TMKDMGVYTLDMTDENYRRTQATVRFHVH 141
Cdd:pfam07686  81 TLSDSGTYTCAVIPSGEGVFGKGTRLTVL 109

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 85719303    153 NTTVKELDSVTLTC-LSNDIGANIQWLFNSQS-LQLTERMTLSQN--NSILRIDPIKREDAGEYQCEISNPVSVRRSN 226
Cdd:smart00410   3 SVTVKEGESVTLSCeASGSPPPEVTWYKQGGKlLAESGRFSVSRSgsTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

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 85719303   152 TNTTVKELDSVTLTCLSNDI--GANIQWLFNSQSLQLTERMTLSQNNSI---LRIDPIKREDAGEYQCEISNPVSVRRSN 226
Cdd:pfam00047   4 PTVTVLEGDSATLTCSASTGspGPDVTWSKEGGTLIESLKVKHDNGRTTqssLLISNVTKEDAGTYTCVVNNPGGSATLS 83

                  ..
gi 85719303   227 SI 228
Cdd:pfam00047  84 TS 85

Fourth immunoglobulin (Ig)-like domain of hemolin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain of hemolin and similar proteins. Hemolin, an insect immunoglobulin superfamily (IgSF) member containing four Ig-like domains, is a lipopolysaccharide-binding immune protein induced during bacterial infection. Hemolin shares significant sequence similarity with the first four Ig-like domains of the transmembrane cell adhesion molecules (CAMs) of the L1 family. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The fourth Ig-like domain of hemolin is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 85719303 152 TNTTVKELDSVTLTC-LSNDIGANIQWLFNSQSLQ-LTERMTLSQNnsILRIDPIKREDAGEYQCEISN 218
Cdd:cd20978   9 KNVVVKGGQDVTLPCqVTGVPQPKITWLHNGKPLQgPMERATVEDG--TLTIINVQPEDTGYYGCVATN 75

Third immunoglobulin domain in Cluster of Differentiation (CD) 22; member of the Constant 2 (C2)-set of IgSF domains; The members here are composed of the third immunoglobulin domain in Cluster of Differentiation (CD) 22 (also known as Siglec-2). CD22, a sialic-acid binding immunoglobulin type-lectin (Siglec) family member, is an inhibitory co-receptor of the B-cell receptor (BCR). The inhibitory function of CD22 and its restricted expression on B cells makes CD22 an attractive target against dysregulated B cells that cause autoimmune diseases and B-cell-derived cancers. CD22 plays a vital role in establishing a baseline level of B-cell inhibition, and thus is an important determinant of homeostasis in humoral immunity. Siglecs are primarily expressed on immune cells and recognize sialic acid-containing glycan ligands. Siglecs are organized as an extracellular module composed of Ig-like domains (an N-terminal variable set of Ig-like carbohydrate recognition domains, and 1 to 16 constant Ig-like domains), followed by transmembrane and short cytoplasmic domains. Human Siglecs are classified into two subgroups, one subgroup is comprised of sialoadhesin (Siglec-1), CD22 (Siglec-2), and MAG (Siglec-4, myelin-associated glycoprotein), the other subgroup is comprised of CD33-related Siglecs which include CD33 (Siglec-3) and human Siglecs 5-11. 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        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 85719303 152 TNTTVKELDSVTLTC---LSNDIGANIQWLFNSQSLQltermtlSQNNSILRIDPIKREDAGEYQCEISNPVSVRRSNSI 228
Cdd:cd20937  10 SDAIVREGDSVTMTCevsSSNPEYTTVSWLKDGTSLK-------KQNTFTLNLREVTKDQSGKYCCQVSNDVGPGRSEEV 82

                ....*.
gi 85719303 229 KLDIIF 234
Cdd:cd20937  83 FLQVQY 88

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 85719303 143 PVTQPFLQVTNTTVKELDSVTLTCL-SNDIGANIQWLFNSQSLQ-LTERMTLSQNNSILRIDPIKREDAGEYQCEISNPV 220
Cdd:cd20970   1 PVISTPQPSFTVTAREGENATFMCRaEGSPEPEISWTRNGNLIIeFNTRYIVRENGTTLTIRNIRRSDMGIYLCIASNGV 80

                        90
                ....*....|..
gi 85719303 221 SVRRSNSIKLDI 232
Cdd:cd20970  81 PGSVEKRITLQV 92

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

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 85719303 154 TTVKELDSVTLTCLsndiGAN------IQWLFNSQSLQltermtlSQNNSIlRIDPIKREDAGEYQCEI-----SNPV 220
Cdd:cd05752  10 TTVFQGEKVTLTCQ----GFYspeqnsTQWYHNGTLIS-------STSSSY-RIVAATVNDSGEYRCQTqgsslSDPV 75

Domain C2 of human cardiac Myosin Binding Protein C and similar domains; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) Domain C2 of human cardiac Myosin Binding Protein C (MyBP-C) and similar domains. MyBP-C is a thick filament protein involved in the regulation of muscle contraction. Mutations in cardiac MyBP-C gene are the second most frequent cause of hypertrophic cardiomyopathy. MyBP-C binds to myosin with two binding sites, one at its C-terminus and another at its N-terminus. The N-terminal binding site, consisting of immunoglobulin (lg) domains C1 and C2 connected by a flexible linker, interacts with the S2 segment of myosin in a phosphorylation-regulated manner. The C1 and C2 Ig domains can bind to and activate or inhibit the thin filament. 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 structures of the Ig domains of MyBP-C lack this strand and thus belong to the I-set of Ig superfamily domains. 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 85719303 146 QPFLQVTNTTvkeldSVTLTCLSNDIGANIQWLFNSQSLQLTERMTLSQNNS--ILRIDPIKREDAGEYQC 214
Cdd:cd20967   4 QPAVQVSKGH-----KIRLTVELADPDAEVKWYKDGQELQSSSKVIFESIGAkrTLTVQQASLADAGEYQC 69

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

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*
gi 85719303 175 IQWLFNSQSL--QLTERMTLSQNNSILRIDPIKREDAGEYQCEISNPVSVRRSNS 227
Cdd:cd05736  32 VQWLKNGMDInpKLSKQLTLIANGSELHISNVRYEDTGAYTCIAKNEGGVDEDIS 86

Third immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the Constant 2 (C2)-set of IgSF domains; The members here are composed of the third 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. 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, and C' in the other. Unlike other Ig domain sets, the C2-set lacks the D strand.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*....
gi 85719303 163 TLTCLSNDIGA-NIQWLFNSQSLQLTERMTLSQNNsILRIDPIKREDAGEYQCEISNPV 220
Cdd:cd20957  20 VFNCSVTGNPIhTVLWMKDGKPLGHSSRVQILSED-VLVIPSVKREDKGMYQCFVRNDG 77

T-cell surface glycoprotein CD3 delta chain; This is an immunoglobulin-like domain. It is found on the T-cell surface glycoprotein CD3 delta chain. CD3delta and CD3epsilon complex together as part of the T-cell receptor complex.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 85719303   160 DSVTLTCLSNDigANIQWLFNSQSLQLTERMTLSQNNSILridpikrEDAGEYQCEISNPVS 221
Cdd:pfam16680   2 GKVLLTCNSSS--KSITWLKDGKGIKSTNTKTLDLGKFSE-------DPRGLYQCQGEKKKS 54

Immunoglobulin Constant-1 (C1)-set domain; The members here are composed of C1-set domains, classical Ig-like domains resembling the antibody constant domain. Members of the IgC1 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, while the IgC domain is involved in oligomerization and molecular interactions. 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 strands by G, F, C, and C'.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 85719303 146 QPFLQVTNTTVKELDSVTLTCLSNDI---GANIQWLFNSQSLQL--TERMTLSQNN------SILRIDPIKREDAGEYQC 214
Cdd:cd00098   1 TVTLLPPSPEEKGGGKVTLVCLVSGFypkDITVTWLKNGVPLTSgvSTSSPVEPNDgtysvtSSLTVPPSDWDEGATYTC 80

                ....*
gi 85719303 215 EISNP 219
Cdd:cd00098  81 VVTHE 85

N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family; The members here are composed of the N-terminal immunoglobulin (Ig)-like domain of the signaling lymphocyte activation molecule (SLAM) family and similar proteins. The SLAM family is a group of immune-cell specific receptors that can regulate both adaptive and innate immune responses. Members of this group include proteins such as CD84, SLAM (CD150), Ly-9 (CD229), NTB-A (ly-108, SLAM6), 19A (CRACC), and SLAMF9. The genes coding for the SLAM family are nested on chromosome 1, in humans at 1q23, and in mice at 1H2. The SLAM family is a subset of the CD2 family, which also includes CD2 and CD58 located on chromosome 1 at 1p13 in humans. In mice, CD2 is located on chromosome 3, and there is no CD58 homolog. The SLAM family proteins are organized as an extracellular domain with either two or four Ig-like domains, a single transmembrane segment, and a cytoplasmic region having Tyr-based motifs. The extracellular domain is organized as a membrane-distal Ig variable (IgV) domain that is responsible for ligand recognition and a membrane-proximal truncated Ig constant-2 (IgC2) domain.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 85719303 161 SVT--LTCLSNDIGANIQWLFNSQSLQLT-----------------ERMTLSQNNSILRIDPIKREDAGEYQCEIS 217
Cdd:cd16842  10 SVTfpLNISDGQEIENITWSFKTSLAVIApgeggapeiiitdksykERLNISQNDYSLQISNLTMEDAGSYRARIN 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 85719303 152 TNTTVKELDSVTLTCLSNDIGA-NIQWLFNSQSLqLTERMTLSQNNSILRIDPIKREDAGEYQCEISNPV 220
Cdd:cd05731   3 SSTMVLRGGVLLLECIAEGLPTpDIRWIKLGGEL-PKGRTKFENFNKTLKIENVSEADSGEYQCTASNTM 71