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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949    131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHL 210
Cdd:smart00410   4 VTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTL 83

                   ..
gi 45592949    211 IV 212
Cdd:smart00410  84 TV 85

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949    131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHL 210
Cdd:smart00410   4 VTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTL 83

                   ..
gi 45592949    211 IV 212
Cdd:smart00410  84 TV 85

Immunoglobulin domain; The members here are composed of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. Members of this group are components of immunoglobulin, neuroglia, cell surface glycoproteins, including T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, including butyrophilin and chondroitin sulfate proteoglycan core protein. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. Ig superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Typically, the V-set domains have A, B, E, and D strands in one sheet and A', G, F, C, C' and C" in the other. The structures in C1-set are smaller than those in the V-set; they have one beta sheet that is formed by strands A, B, E, and D and the other by strands G, F, C, and C'. Moreover, a C1-set Ig domain contains a short C' strand (three residues) and lacks A' and C" strand. Unlike other Ig domain sets, C2-set structures do not have a D strand. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 45592949 139 VKLVCNVKANPQAQMMWYKNSSLLDlEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTES 205
Cdd:cd00096   1 VTLTCSASGNPPPTITWYKNGKPLP-PSSRDSRRSELGNGTLTISNVTLEDSGTYTCVASNSAGGSA 66

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949    131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHL 210
Cdd:smart00410   4 VTVKEGESVTLSCEASGSPPPEVTWYKQGGKLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTL 83

                   ..
gi 45592949    211 IV 212
Cdd:smart00410  84 TV 85

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949   131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLdLEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHL 210
Cdd:pfam07679  10 VEVQEGESARFTCTVTGTPDPEVSWFKDGQPL-RSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAGEAEASAEL 88

                  ..
gi 45592949   211 IV 212
Cdd:pfam07679  89 TV 90

Immunoglobulin domain I1 of the titin I-band and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin domain I1 of the titin I-band and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. The two sheets are linked together by a conserved disulfide bond between B strand and F strand. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The Ig I1 domain of the titin I-band is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLD--LEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDF 208
Cdd:cd20951  10 HTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDpsSIPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKNIHGEASSSA 89

                ....*
gi 45592949 209 HLIVK 213
Cdd:cd20951  90 SVVVE 94

Second Ig-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. 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 titin Z1z2 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 45592949 131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSllDLEKSRH-QIQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFH 209
Cdd:cd20972  11 QEVAEGSKVRLECRVTGNPTPVVRWFCEGK--ELQNSPDiQIHQEGDLHSLIIAEAFEEDTGRYSCLATNSVGSDTTSAE 88

                ...
gi 45592949 210 LIV 212
Cdd:cd20972  89 IFV 91

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 45592949   132 TVEEGSNVKLVCNVK-ANPQAQMMWYK-NSSLLDLEKSRHQIQQTSeSFQLSITKVEKPDNGTYSCIA 197
Cdd:pfam00047   7 TVLEGDSATLTCSAStGSPGPDVTWSKeGGTLIESLKVKHDNGRTT-QSSLLISNVTKEDAGTYTCVV 73

Third immunoglobulin (Ig)-like domain of peroxidasin; The members here are composed of the third immunoglobulin (Ig)-like domain in peroxidasin. Peroxidasin has a peroxidase domain and interacting extracellular motifs containing four Ig-like domains. It has been suggested that peroxidasin is secreted and has functions related to the stabilization of the extracellular matrix. It may play a part in various other important processes such as removal and destruction of cells which have undergone programmed cell death and protection of the organism against non-self.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 45592949 135 EGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKsRHQIQQtseSFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHLIV 212
Cdd:cd05745   1 EGQTVDFLCEAQGYPQPVIAWTKGGSQLSVDR-RHLVLS---SGTLRISRVALHDQGQYECQAVNIVGSQRTVAQLTV 74

Second immunoglobulin (Ig)-like domain of the receptor protein tyrosine phosphatase (RPTP)-F; member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain found in the receptor protein tyrosine phosphatase (RPTP)-F, also known as LAR. LAR belongs to the RPTP type IIa subfamily. Members of this subfamily are cell adhesion molecule-like proteins involved in central nervous system (CNS) development. They have large extracellular portions comprised of multiple Ig-like domains and two to nine fibronectin type III (FNIII) domains and a cytoplasmic portion having two tandem phosphatase domains.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 45592949 127 GNDFQTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTsESFQLSITKVEKPDNGTYSCIAKSSLKT 203
Cdd:cd05738   5 GPQLKVVEKARTATMLCAASGNPDPEISWFKDFLPVDTATSNGRIKQL-RSGALQIENSEESDQGKYECVATNSAGT 80

C-terminal immunoglobulin (Ig)-like domain of myomesin and M-protein; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the C-terminal immunoglobulin (Ig)-like domain of myomesin and M-protein (also known as myomesin-2). Myomesin and M-protein are both structural proteins localized to the M-band, a transverse structure in the center of the sarcomere, and are candidates for M-band bridges. Both proteins are modular, consisting mainly of repetitive Ig-like and fibronectin type III (FnIII) domains. Myomesin is expressed in all types of vertebrate striated muscle; M-protein has a muscle-type specific expression pattern. Myomesin is present in both slow and fast fibers; M-protein is present only in fast fibers. It has been suggested that myomesin acts as a molecular spring with alternative splicing as a means of modifying its elasticity.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 129 DFQTVEEGSNVKLVCNVKANPQAQMMWYKN-SSLLDLEKSRHQIQQTSESFqLSITKVEKPDNGTYSCIAKSSLKTESLD 207
Cdd:cd05737   9 DVVTIMEGKTLNLTCNVWGDPPPEVSWLKNdQALAFLDHCNLKVEAGRTVY-FTINGVSSEDSGKYGLVVKNKYGSETSD 87

                ....*
gi 45592949 208 FHLIV 212
Cdd:cd05737  88 VTVSV 92

Immunoglobulin (Ig)-like domain in neuregulins; The members here are composed of the immunoglobulin (Ig)-like domain in neuregulins (NRGs). NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. There are four members of the neuregulin gene family (NRG-1, NRG-2, NRG-3, and NRG-4). The NRG-1 protein, binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. The other NRGs proteins bind one or the other or both of these ErbBs. NRG-1 has multiple functions: in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors, while in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. Less is known of the functions of the other NRGs. NRG-2 and NRG-3 are expressed predominantly in the nervous system. NRG-2 is expressed by motor neurons and terminal Schwann cells, and is concentrated near synaptic sites and may be a signal that regulates synaptic differentiation. NRG-4 has been shown to direct pancreatic islet cell development towards the delta-cell lineage.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 45592949 131 QTVEEGSNVKLVCNVKA-NPQAQMMWYKNSSLLDLEKSRH-QIQQTSESFQLSITKVEKPDNGTYSCIAKSSL 201
Cdd:cd05750   9 QTVQEGSKLVLKCEATSeNPSPRYRWFKDGKELNRKRPKNiKIRNKKKNSELQINKAKLEDSGEYTCVVENIL 81

agrin-responsive second immunoglobulin-like domains (Ig2) of the Muscle-specific kinase (MuSK) ectodomain; a member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin-like (Ig) domains of the Muscle-specific kinase (MuSK) ectodomain. MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 45592949 132 TVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDlEKSRHQIQqtsESFQLSITKVEKPDNGTYSCIAKSSLKT 203
Cdd:cd20968  10 TIIEGLKAVLPCTTMGNPKPSVSWIKGDDLIK-ENNRIAVL---ESGSLRIHNVQKEDAGQYRCVAKNSLGI 77

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        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSllDLEKSRHQIqqtsESFQ--LSITKVEKPDNGTYSCIAKSSLKTESLDF 208
Cdd:cd05731   5 TMVLRGGVLLLECIAEGLPTPDIRWIKLGG--ELPKGRTKF----ENFNktLKIENVSEADSGEYQCTASNTMGSARHTI 78

                ....*
gi 45592949 209 HLIVK 213
Cdd:cd05731  79 SVTVE 83

First immunoglobulin (Ig)-like constant domain in Robo (roundabout) receptors, and similar domains; The members here are composed of the first immunoglobulin (Ig)-like domain in Roundabout (Robo) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, and Robo3), and three mammalian Slit homologs (Slit1, Slit2, Slit3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit1, Slit2,and Slit3 are expressed at the ventral midline. Robo3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 45592949 132 TVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEK----SRHQIQQTSESFQLSIT--KVEKPDNGTYSCIAKSSLKT 203
Cdd:cd07693  11 IVSKGDPATLNCKAEGRPTPTIQWLKNGQPLETDKddprSHRIVLPSGSLFFLRVVhgRKGRSDEGVYVCVAHNSLGE 88

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 45592949 119 VTFPPLlsgndFQTVEEGSNVKLVCNVK-ANPQAQMMWYK----------------NSSLLDLEKSR-HQIQQTSESFQL 180
Cdd:cd00099   1 VTQSPR-----SLSVQEGESVTLSCEVSsSFSSTYIYWYRqkpgqgpefliylsssKGKTKGGVPGRfSGSRDGTSSFSL 75

                        90       100
                ....*....|....*....|....*...
gi 45592949 181 SITKVEKPDNGTYSCIAKSSLKTESLDF 208
Cdd:cd00099  76 TISNLQPEDSGTYYCAVSESGGTDKLTF 103

Second immunoglobulin (Ig)-like domain in Robo (roundabout) receptors; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig)-like domain in Robo (roundabout) receptors. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of the Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, Robo2, and Robo3), and three mammalian Slit homologs (Slit-1,Slit-2, Slit-3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, Robo2, and Robo3 are expressed by commissural neurons in the vertebrate spinal cord and Slit-1, Slit-2, Slit-3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of Slit responsiveness, antagonizes Slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit-2 has been shown by surface plasmon resonance experiments and mutational analysis to be the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 45592949 149 PQAQMMWYKNSSLLDLEKSRHQIQqtsESFQLSITKVEKPDNGTYSCIAKSSLKT-ESLDFHLIV 212
Cdd:cd05724  26 PEPTVSWRKDGQPLNLDNERVRIV---DDGNLLIAEARKSDEGTYKCVATNMVGErESRAARLSV 87

Immunoglobulin I-set domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1); The members here are composed of the immunoglobulin I-set (IgI) domain of the Leucine-rich repeat and immunoglobin-like domain-containing protein 1 (Lingo-1). Human Lingo-1 is a central nervous system-specific transmembrane glycoprotein also known as LERN-1, which functions as a negative regulator of neuronal survival, axonal regeneration, and oligodendrocyte differentiation and myelination. Lingo-1 is a key component of the Nogo receptor signaling complex (RTN4R/NGFR) in RhoA activation responsible for some inhibition of axonal regeneration by myelin-associated factors. The ligand-binding ectodomain of human Lingo-1 contains a bimodular, kinked structure composed of leucine-rich repeat (LRR) and immunoglobulin (Ig)-like modules. Diseases associated with Lingo-1 include mental retardation, autosomal recessive 64 and essential tremor. 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 Lingo-1 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 45592949 128 NDFQTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSESfQLSITKVEKPDNGTYSCIAKSSLKTESLD 207
Cdd:cd20969   9 AQQVFVDEGHTVQFVCRADGDPPPAILWLSPRKHLVSAKSNGRLTVFPDG-TLEVRYAQVQDNGTYLCIAANAGGNDSMP 87

                ....*
gi 45592949 208 FHLIV 212
Cdd:cd20969  88 AHLHV 92

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        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 45592949 131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLdleKSRHQIQQTSESfQLSITKVEKPDNGTYSCIA 197
Cdd:cd20957  11 QTVDFGRTAVFNCSVTGNPIHTVLWMKDGKPL---GHSSRVQILSED-VLVIPSVKREDKGMYQCFV 73

Fifth Ig-like domain of Roundabout (Robo) homolog 1/2, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the fifth Ig-like domain of Roundabout (Robo) homolog 1/2 and similar domains. Robo receptors play a role in the development of the central nervous system (CNS), and are receptors of Slit protein. Slit is a repellant secreted by the neural cells in the midline. Slit acts through Robo to prevent most neurons from crossing the midline from either side. Three mammalian Robo homologs (Robo1, -2, and -3), and three mammalian Slit homologs (Slit-1,-2, -3), have been identified. Commissural axons, which cross the midline, express low levels of Robo; longitudinal axons, which avoid the midline, express high levels of Robo. Robo1, -2, and -3 are expressed by commissural neurons in the vertebrate spinal cord and Slits 1, -2, -3 are expressed at the ventral midline. Robo-3 is a divergent member of the Robo family which instead of being a positive regulator of slit responsiveness, antagonizes slit responsiveness in precrossing axons. The Slit-Robo interaction is mediated by the second leucine-rich repeat (LRR) domain of Slit and the two N-terminal Ig domains of Robo, Ig1 and Ig2. The primary Robo binding site for Slit2 has been shown by surface plasmon resonance experiments and mutational analysis to be is the Ig1 domain, while the Ig2 domain has been proposed to harbor a weak secondary binding site. The fifth Ig-like domain of Robo 1 and 2 is a member of the I-set Ig domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand but lack a C" strand. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 124 LLSGNDFQTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSesfQLSITKVEKPDNGTYSCIAKSSLKT 203
Cdd:cd20952   2 ILQGPQNQTVAVGGTVVLNCQATGEPVPTISWLKDGVPLLGKDERITTLENG---SLQIKGAEKSDTGEYTCVALNLSGE 78

                ..
gi 45592949 204 ES 205
Cdd:cd20952  79 AT 80

Fourth Ig-like domain from smooth muscle myosin light chain kinase and similar domains ; a member of the I-set of IgSF domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain from smooth muscle myosin light chain kinase (MYLK) and similar domains. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of this group shows that the fourth Ig-like domain from myosin light chain kinase lacks this strand and thus belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 45592949 132 TVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQ-QTSEsfqLSITKVEKPDNGTYSCIAKSSLKTES 205
Cdd:cd20976  12 EAVEGQDFVAQCSARGKPVPRITWIRNAQPLQYAADRSTCEaGVGE---LHIQDVLPEDHGTYTCLAKNAAGQVS 83

Third immunoglobulin (Ig) domain of contactin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig) domain of contactins. Contactins are neural cell adhesion molecules and are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. The first four Ig domains form the intermolecular binding fragment, which arranges as a compact U-shaped module via contacts between Ig domains 1 and 4, and between Ig domains 2 and 3. Contactin-2 (TAG-1, axonin-1) may play a part in the neuronal processes of neurite outgrowth, axon guidance and fasciculation, and neuronal migration. This group also includes contactin-1 and contactin-5. The different contactins show different expression patterns in the central nervous system. During development and in adulthood, contactin-2 is transiently expressed in subsets of central and peripheral neurons. Contactin-5 is expressed specifically in the rat postnatal nervous system, peaking at about 3 weeks postnatal, and a lack of contactin-5 (NB-2) results in an impairment of neuronal activity in the rat auditory system. Contactin-5 is highly expressed in the adult human brain in the occipital lobe and in the amygdala. Contactin-1 is differentially expressed in tumor tissues and may, through a RhoA mechanism, facilitate invasion and metastasis of human lung adenocarcinoma. This group belongs to the I-set of IgSF domains.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 45592949 136 GSNVKLVCNVKANPQAQMMWYKnsslLDLEKSRHQIQQTSESFqLSITKVEKPDNGTYSCIAKSS 200
Cdd:cd04968  16 GQTVTLECFALGNPVPQIKWRK----VDGSPSSQWEITTSEPV-LEIPNVQFEDEGTYECEAENS 75

Second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor; member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor. FGF receptors bind FGF signaling polypeptides. FGFs participate in multiple processes such as morphogenesis, development, and angiogenesis. FGFs bind to four FGF receptor tyrosine kinases (FGFR1, FGFR2, FGFR3, FGFR4). Receptor diversity is controlled by alternative splicing producing splice variants with different ligand binding characteristics and different expression patterns. FGFRs have an extracellular region comprised of three IG-like domains, a single transmembrane helix, and an intracellular tyrosine kinase domain. Ligand binding and specificity reside in the Ig-like domains 2 and 3, and the linker region that connects these two. FGFR activation and signaling depend on FGF-induced dimerization, a process involving cell surface heparin or heparin sulfate proteoglycans.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 133 VEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLE------KSRHQIQqtsesfQLSITKVEKPDNGTYSCIAKSSLKTESL 206
Cdd:cd05857  16 VPAANTVKFRCPAAGNPTPTMRWLKNGKEFKQEhriggyKVRNQHW------SLIMESVVPSDKGNYTCVVENEYGSINH 89

                ....*.
gi 45592949 207 DFHLIV 212
Cdd:cd05857  90 TYHLDV 95

Immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1; The members here are composed of the immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. NRG-1 belongs to the neuregulin gene family which is comprised of four genes. This group represents NRG-1. NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, and heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. The NRG-1 protein binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. NRG-1 has multiple functions, for example, in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 131 QTVEEGSNVKLVCN-VKANPQAQMMWYKNSSLLDlEKSRHQ---IQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESL 206
Cdd:cd05895   9 QEVAAGSKLVLRCEtSSEYPSLRFKWFKNGKEIN-RKNKPEnikIQKKKKKSELRINKASLADSGEYMCKVSSKLGNDSA 87

                ....*.
gi 45592949 207 DFHLIV 212
Cdd:cd05895  88 SANVTI 93

Immunoglobulin (Ig)-like ectodomain of the LRIG1 (Leucine-rich Repeats And Immunoglobulin-like Domains Protein 1) and similar proteins; member of the I-set of IgSF domains; The members here are composed of subgroup of the immunoglobulin (Ig) domain found in the Ig superfamily. The Ig superfamily is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. A predominant feature of most Ig domains is a disulfide bridge connecting the two beta-sheets with a tryptophan residue packed against the disulfide bond. The ectodomain of LRIG1 has two distinct regions: the proposed 15 LRRs and three Ig-like domains closer to the membrane. LRIG1 has been reported to interact with many receptor tyrosine kinases, GDNF/c-Ret, E-cadherin, JAK/STAT, c-Met, and the EGFR family signaling systems. Immunoglobulin Superfamily (IgSF) domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. The structure of the LRIG1 extracellular Ig domain lacks a C" strand and thus is better described as a member of the I-set of IgSF domains.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 132 TVEEGSNVKLVCNVKANPQAQMMWYKNSSLlDLEKSRHQ-IQQTSESFQLSITKVEKPDNGTYSCIAKSSLKTESLDFHL 210
Cdd:cd05763  10 TIRAGSTARLECAATGHPTPQIAWQKDGGT-DFPAARERrMHVMPEDDVFFIVDVKIEDTGVYSCTAQNSAGSISANATL 88

                ..
gi 45592949 211 IV 212
Cdd:cd05763  89 TV 90

Fifth immunoglobulin (Ig) domain of contactin-1; The members here are composed of the fifth immunoglobulin (Ig) domain of the neural cell adhesion molecule contactin-1. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-1 is differentially expressed in tumor tissues and may through a RhoA mechanism, facilitate invasion and metastasis of human lung adenocarcinoma.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 45592949 135 EGSNVKLVCNVKANPQAQMMWYKNSSLLdLEKSRHQIQqtsESFQLSITKVEKPDNGTYSCIAKSS 200
Cdd:cd05852  16 KGGRVIIECKPKAAPKPKFSWSKGTELL-VNNSRISIW---DDGSLEILNITKLDEGSYTCFAENN 77

Immunoglobulin-like domain of human nephrin and similar proteins; member of the C1-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin-like domain in human nephrin and similar proteins. Nephrin is an integral component of the slit diaphragm and is a central component of the glomerular ultrafilter. Nephrin plays a structural role and has a role in signaling. Nephrin is a transmembrane protein having a short intracellular portion, an extracellular portion comprised of eight Ig-like domains, and one fibronectin type III-like domain. The extracellular portions of nephrin from neighboring foot processes of separate podocyte cells may interact with each other, and in association with other components of the slit diaphragm form a porous molecular sieve within the slit pore. The intracellular portion of nephrin is associated with linker proteins, which connect nephrin to the actin cytoskeleton. The intracellular portion is tyrosine phosphorylated, and mediates signaling from the slit diaphragm into the podocytes.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 135 EGSNV-KLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSE----SFQLSITKVEKP-DNGTYSCIAKSSLKTESLDF 208
Cdd:cd05773  21 DGSSDaNLVCQAQGVPRVQFRWAKNGVPLDLGNPRYEETTEHTgtvhTSILTIINVSAAlDYALFTCTAHNSLGEDSLDI 100

                ...
gi 45592949 209 HLI 211
Cdd:cd05773 101 QLV 103

Second immunoglobulin (Ig)-like domain of interleukin-1 receptor (IL1R), and similar domains; The members here are composed of the second immunoglobulin (Ig)-like domain of interleukin-1 receptor (IL1R; also known as cluster of differentiation (CD) 121). IL-1 alpha and IL-1 beta are cytokines which participate in the regulation of inflammation, immune responses, and hematopoiesis. These cytokines bind to the IL-1 receptor type 1 (IL1R1), which is activated on additional association with interleukin-1 receptor accessory protein (IL1RAP). IL-1 also binds a second receptor designated type II (IL1R2). Mature IL1R1 consists of three IG-like domains, a transmembrane domain, and a large cytoplasmic domain. Mature IL1R2 is organized similarly except that it has a short cytoplasmic domain. The latter does not initiate signal transduction. A naturally occurring cytokine IL-1RA (IL-1 receptor antagonist) is widely expressed and binds to IL-1 receptors, inhibiting the binding of IL-1 alpha and IL-1 beta. This group also contains ILIR-like 1 (IL1R1L) which maps to the same chromosomal location as IL1R1 and IL1R2.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 45592949 131 QTVEEGSNVKLVC-------NVKANPQAQmmWYKNSSLLDLEKSRHQIqqtsESFqLSITKVEKPDNGTYSCIAK 198
Cdd:cd05757   5 QKLPITKGGKITCpdlddykNENVLPPIQ--WYKDCKPLQGDKRFIPK----GSK-LLIQNVTEEDAGNYTCKFT 72

Immunoglobulin-like domain of human Aortic Preferentially Expressed Protein-1 (APEG-1) and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin I-set (IgI) domain of the Human Aortic Preferentially Expressed Protein-1 (APEG-1) and similar proteins. APEG-1 is a novel specific smooth muscle differentiation marker predicted to play a role in the growth and differentiation of arterial smooth muscle cells (SMCs). 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 human APEG-1 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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 45592949 131 QTVEEGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSESFQLSITKVEKPDNGTYSCIA 197
Cdd:cd20975  10 QSVREGQDVIMSIRVQGEPKPVVSWLRNRQPVRPDQRRFAEEAEGGLCRLRILAAERGDAGFYTCKA 76

Immunoglobulin (Ig)-like domain of vascular endothelial growth factor receptor 2 (VEGFR-2); member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain of vascular endothelial growth factor receptor 2 (VEGFR-2). The VEGFRs have an extracellular component with seven Ig-like domains, a transmembrane segment, and an intracellular tyrosine kinase domain interrupted by a kinase-insert domain. VEGFRs bind VEGFs with high affinity at the Ig-like domains. VEGFR-2 (KDR/Flk-1) is a major mediator of the mitogenic, angiogenic and microvascular permeability-enhancing effects of VEGF-A; VEGF-A is important to the growth and maintenance of vascular endothelial cells and to the development of new blood- and lymphatic-vessels in physiological and pathological states. VEGF-A also interacts with VEGFR-1, which it binds more strongly than VEGFR-2. VEGFR-1 and VEGFR-2 may mediate a chemotactic and a survival signal in hematopoietic stem cells or leukemia cells. This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 45592949 125 LSGNDFQTVEE--GSNVKLVCNVKANPQAQMMWYKNSSLLDlekSRHQIQQtseSFQLSITKVEKPDNGTYSCIA--KSS 200
Cdd:cd05864   4 LGSGMESLVEAkvGERVRIPVKYLGYPPPEIKWYKNGIPIE---SNHTIKA---GHVLTIMEVTEKDAGNYTVVLtnPIS 77

                        90
                ....*....|..
gi 45592949 201 LKTESLDFHLIV 212
Cdd:cd05864  78 KEKQRHTFSLVV 89

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 45592949 132 TVEEGSNVKLVCNVK--ANPQAQMMWYKNSSLLDLEKS-RHQIQQTSESFQ----LSITKVEKPDNGTYSCIAK--SSLK 202
Cdd:cd00098  10 EEKGGGKVTLVCLVSgfYPKDITVTWLKNGVPLTSGVStSSPVEPNDGTYSvtssLTVPPSDWDEGATYTCVVTheSLKS 89

                ....*.
gi 45592949 203 TESLDF 208
Cdd:cd00098  90 PLSKTW 95

First C-terminal immunoglobulin (Ig)-like domain of palladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the C-terminal immunoglobulin (Ig)-like domain of palladin. Palladin belongs to the palladin-myotilin-myopalladin family. Proteins belonging to this family contain multiple Ig-like domains and function as scaffolds, modulating actin cytoskeleton. Palladin binds to alpha-actinin ezrin, vasodilator-stimulated phosphoprotein VASP, SPIN90 (also known as DIP or mDia interacting protein), and Src. Palladin also binds F-actin directly, via its Ig3 domain. Palladin is expressed as several alternatively spliced isoforms, having various combinations of Ig-like domains, in a cell-type-specific manner. It has been suggested that palladin's different Ig-like domains may be specialized for distinct functions. This group belongs to the I-set of IgSF domains, having A-B-E-D strands in one beta-sheet and A'-G-F-C-C' in the other. Like the V-set Ig domains, members of the I-set have a discontinuous A strand, but lack a C" strand.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 45592949 135 EGSNVKLVCNVKANPQAQMMWYKNSSLLDLEKSRHQIQQTSE-SFQLSITKVEKPDNGTYSCIA 197
Cdd:cd05893  14 EGMPVTFTCRVAGNPKPKIYWFKDGKQISPKSDHYTIQRDLDgTCSLHTTASTLDDDGNYTIMA 77

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
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 45592949 123 PLLSGNDFQTVEEGSNVKLVCNvKANPQAQMMWYKNSSLLDLEksrHQIQQTSESFQLSITKVEKPDNGTYSC 195
Cdd:cd05740   2 PFISSNNSNPVEDKDAVTLTCE-PETQNTSYLWWFNGQSLPVT---PRLTLSNGNRTLTLLNVTREDAGAYQC 70