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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  105 LCFLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKN 184
Cdd:cd20951      1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPSSIPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                           90
                   ....*....|....
gi 2131042730  185 CSGMICCSASLEVK 198
Cdd:cd20951     81 IHGEASSSASVVVE 94

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 2131042730  105 LCFLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKN 184
Cdd:cd20951      1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPSSIPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                           90
                   ....*....|....
gi 2131042730  185 CSGMICCSASLEVK 198
Cdd:cd20951     81 IHGEASSSASVVVE 94

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

                            10        20        30        40        50        60        70        80
                    ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730   113 SQKVPEKSDAVLRCMISGQPKPEVTWYKNGraIDECGIVSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKNCSGMICCS 192
Cdd:smart00410    3 SVTVKEGESVTLSCEASGSPPPEVTWYKQG--GKLLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSG 80

                    ....*
gi 2131042730   193 ASLEV 197
Cdd:smart00410   81 TTLTV 85

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 2131042730  105 LCFLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKN 184
Cdd:cd20951      1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPSSIPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                           90
                   ....*....|....
gi 2131042730  185 CSGMICCSASLEVK 198
Cdd:cd20951     81 IHGEASSSASVVVE 94

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 2131042730  113 SQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDEcgiVSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKN 184
Cdd:pfam13927   10 SVTVREGETVTLTCEATGSPPPTITWYKNGEPISS---GSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin (Ig)-like domain of myotilin, palladin, and myopalladin; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the immunoglobulin (Ig)-like domain in myotilin, palladin, and myopalladin. Myotilin, palladin, and myopalladin function as scaffolds that regulate actin organization. Myotilin and myopalladin are most abundant in skeletal and cardiac muscle; palladin is ubiquitously expressed in the organs of developing vertebrates and plays a key role in cellular morphogenesis. The three family members each interact with specific molecular partners with all three binding to alpha-actinin; In addition, palladin also binds to vasodilator-stimulated phosphoprotein (VASP) and ezrin, myotilin binds to filamin and actin, and myopalladin also binds to nebulin and cardiac ankyrin repeat protein (CARP). 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 2131042730  107 FLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEffQNQYIHLLHLYRCTPGDTAVYQISAKNCS 186
Cdd:cd05744      3 FLQAPGDLEVQEGRLCRFDCKVSGLPTPDLFWQLNGKPVRPDSAHKMLV--RENGRHSLIIEPVTKRDAGIYTCIARNRA 80

                           90
                   ....*....|.
gi 2131042730  187 GMICCSASLEV 197
Cdd:cd05744     81 GENSFNAELVV 91

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        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  107 FLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEffqnQYIHLLHLYRCTPGDTAVYQISAKNCS 186
Cdd:cd20976      4 FSSVPKDLEAVEGQDFVAQCSARGKPVPRITWIRNAQPLQYAADRSTCE----AGVGELHIQDVLPEDHGTYTCLAKNAA 79

                           90
                   ....*....|.
gi 2131042730  187 GMICCSASLEV 197
Cdd:cd20976     80 GQVSCSAWVTV 90

immunoglobulin-like domain of telokin and similar proteins; a member of the I-set of IgSF domains; The members here are composed of the immunoglobulin (Ig) domain in telokin, the C-terminal domain of myosin light chain kinase which is identical to telokin, and similar proteins. 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 telokin Ig domain 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 2131042730  110 TLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECgivSSYEFFQNQ-YIHLLHLYRCTPGDTAVYQISAKNCSGM 188
Cdd:cd20973      3 TLRDKEVVEGSAARFDCKVEGYPDPEVKWMKDDNPIVES---RRFQIDQDEdGLCSLIISDVCGDDSGKYTCKAVNSLGE 79

                   ....*....
gi 2131042730  189 ICCSASLEV 197
Cdd:cd20973     80 ATCSAELTV 88

Fourth immunoglobulin (Ig)-like domain of L1, Ng-CAM (Neuron-glia CAM cell adhesion molecule), and NrCAM (Ng-CAM-related); The members here are composed of the fourth immunoglobulin (Ig)-like domain of L1, Ng-CAM (Neuron-glia CAM cell adhesion molecule), and NrCAM (Ng-CAM-related). These proteins belong to the L1 subfamily of cell adhesion molecules (CAMs) and are comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. These molecules are primarily expressed in the nervous system. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, or spastic paraplegia type 1, that involves abnormalities of axonal growth.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2131042730  120 SDAVLRCMISGQPKPEVTWYKNGRAIDEcgivSSYEFFQNQYIHLLHLYRCTPGDTAVYQISAKNCSGMICCSASLEV 197
Cdd:cd04978     15 ETGELICEAEGNPQPTITWRLNGVPIEP----APEDMRRTVDGRTLIFSNLQPNDTAVYQCNASNVHGYLLANAFLHV 88

Fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM); The members here are composed of the fourth immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 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.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 2131042730  122 AVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEFFQNQYIhllhLYRCTPGDTAVYQISAKNCSGMICCSASLEV 197
Cdd:cd05867     17 ARLDCQVEGIPTPNITWSINGAPIEGTDPDPRRHVSSGALI----LTDVQPSDTAVYQCEARNRHGNLLANAHVHV 88

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        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  114 QKVPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVssyeffQNQYIHLLHLYRCTPGDTAVYQISAKNCSGMICCSA 193
Cdd:cd20957     11 QTVDFGRTAVFNCSVTGNPIHTVLWMKDGKPLGHSSRV------QILSEDVLVIPSVKREDKGMYQCFVRNDGDSAQATA 84

                   ....
gi 2131042730  194 SLEV 197
Cdd:cd20957     85 ELKL 88

Fourth immunoglobulin (Ig)-like domain in neogenin, and similar domains; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the fourth immunoglobulin (Ig)-like domain in neogenin and related proteins. Neogenin is a cell surface protein which is expressed in the developing nervous system of vertebrate embryos in the growing nerve cells. It is also expressed in other embryonic tissues, and may play a general role in developmental processes such as cell migration, cell-cell recognition, and tissue growth regulation. Included in this group is the tumor suppressor protein DCC which is deleted in colorectal carcinoma. DCC and neogenin each have four Ig-like domains followed by six fibronectin type III domains, a transmembrane domain, and an intracellular domain. 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
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 2131042730  118 EKSDAVLRCMISGQPKPEVTWYKNGRAIdecgIVSSYefFQNQYIHLLHLYRCTPGDTAVYQISAKNCSGMICCSASL 195
Cdd:cd05723     11 ESMDIVFECEVTGKPTPTVKWVKNGDVV----IPSDY--FKIVKEHNLQVLGLVKSDEGFYQCIAENDVGNAQASAQL 82

C-terminal immunoglobulin-like domain of the myosin-associated giant protein kinase Twitchin, and similar domains; member of the I-set IgSF domains; The members here are composed of the C-terminal immunoglobulin-like domain of the myosin-associated giant protein kinase Twitchin and similar proteins, including Caenorhabditis elegans and Aplysia californica Twitchin, Drosophila melanogaster Projectin, and similar proteins. These are very large muscle proteins containing multiple immunoglobulin (Ig)-like and fibronectin type III (FN3) domains and a single kinase domain near the C-terminus. In humans these proteins are called Titin. 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. The Ig-like domain of the Twitchin is a member of the I-set 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. 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.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 2131042730  116 VPEKSDAVLRCMISGQPKPEVTWYKNGRAIDEcGIVSSYEFFQNQYIHLLHlyRCTPGDTAVYQISAKNCSGM 188
Cdd:cd20949     11 VKEGQSATILCEVKGEPQPNVTWHFNGQPISA-SVADMSKYRILADGLLIN--KVTQDDTGEYTCRAYQVNSI 80

Second immunoglobulin (Ig)-like domain of protein tyrosine kinase (PTK) 7; The members here are composed of the second immunoglobulin (Ig)-like domain in protein tyrosine kinase (PTK) 7, also known as CCK4. PTK7 is a subfamily of the receptor protein tyrosine kinase family, and is referred to as an RPTK-like molecule. RPTKs transduce extracellular signals across the cell membrane and play important roles in regulating cell proliferation, migration, and differentiation. PTK7 is organized as an extracellular portion having seven Ig-like domains, a single transmembrane region, and a cytoplasmic tyrosine kinase-like domain. PTK7 is considered a pseudokinase as it has several unusual residues in some of the highly conserved tyrosine kinase (TK) motifs; it is predicted to lack TK activity. PTK7 may function as a cell-adhesion molecule. PTK7 mRNA is expressed at high levels in placenta, melanocytes, liver, lung, pancreas, and kidney. PTK7 is overexpressed in several cancers, including melanoma and colon cancer lines.

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 2131042730  119 KSDAVLRCMISGQPKPEVTWYKNGRAIDECG---IVSSYEffqnqyiHLLHLYRCTPGDTAVYQISAKNCSGMICCS 192
Cdd:cd05760     16 SSRVTLRCHIDGHPRPTYQWFRDGTPLSDGQgnySVSSKE-------RTLTLRSAGPDDSGLYYCCAHNAFGSVCSS 85

Second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor_like-1(FGFRL1); 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 like-1(FGFRL1). FGFRL1 is comprised of a signal peptide, three extracellular Ig-like modules, a transmembrane segment, and a short intracellular domain. FGFRL1 is expressed preferentially in skeletal tissues. Similar to FGF receptors, the expressed protein interacts specifically with heparin and with FGF2. FGFRL1 does not have a protein tyrosine kinase domain at its C-terminus; neither does its cytoplasmic domain appear to interact with a signaling partner. It has been suggested that FGFRL1 may not have any direct signaling function, but instead acts as a decoy receptor trapping FGFs and preventing them from binding other receptors.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  117 PEKSDAVLRCMISGQPKPEVTWYKNGRAID--ECGIVSSYEFfqnqyihLLHLYRCTPGDTAVYQISAKNCSGMICCSAS 194
Cdd:cd05856     17 PVGSSVRLKCVASGNPRPDITWLKDNKPLTppEIGENKKKKW-------TLSLKNLKPEDSGKYTCHVSNRAGEINATYK 89

                   ...
gi 2131042730  195 LEV 197
Cdd:cd05856     90 VDV 92

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
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 2131042730  124 LRCMISGQPKPEVTWYKNGRAI---DECgivsSYEFFQNQYIHLLhLYRCTPGDTAVYQISAKNCSG 187
Cdd:cd05737     21 LTCNVWGDPPPEVSWLKNDQALaflDHC----NLKVEAGRTVYFT-INGVSSEDSGKYGLVVKNKYG 82

Second immunoglobulin (Ig)-like domain of fibroblast growth factor (FGF) receptor, and similar domains; 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. This group also contains fibroblast growth factor (FGF) receptor like-1(FGFRL1). FGFRL1 does not have a protein tyrosine kinase domain at its C-terminus; neither does its cytoplasmic domain appear to interact with a signaling partner. It has been suggested that FGFRL1 may not have any direct signaling function, but instead acts as a decoy receptor trapping FGFs and preventing them from binding other receptors.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  116 VPEKSDAVLRCMISGQPKPEVTWYKNGRAIDECGIVSSYEFFQNQYIhlLHLYRCTPGDTAVYQISAKNCSGMICCSASL 195
Cdd:cd05729     16 LPAANKVRLECGAGGNPMPNITWLKDGKEFKKEHRIGGTKVEEKGWS--LIIERAIPRDKGKYTCIVENEYGSINHTYDV 93

                   ..
gi 2131042730  196 EV 197
Cdd:cd05729     94 DV 95

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        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 2131042730  107 FLSTLLSQKVPEKSDAVLRCMISGQPKPEVTWYKNGRAI--DECGIVSSYEffqnQYIHLLHLYRCTPGDTAVYQISAKN 184
Cdd:cd20975      3 FKVSLMDQSVREGQDVIMSIRVQGEPKPVVSWLRNRQPVrpDQRRFAEEAE----GGLCRLRILAAERGDAGFYTCKAVN 78

                           90
                   ....*....|...
gi 2131042730  185 CSGMICCSASLEV 197
Cdd:cd20975     79 EYGARQCEARLEV 91