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 1274095709 189 TYIRQVGESVNLQIPFQGKPKPQVSWTHNGHALDN-QRVNVRSGDQDSILFIRSAQRADSGRYELTVHLEGLEAKASIDI 267
Cdd:cd05748     1 TIVVRAGESLRLDIPIKGRPTPTVTWSKDGQPLKEtGRVQIETTASSTSLVIKNAKRSDSGKYTLTLKNSAGEKSATINV 80

                  ..
gi 1274095709 268 LV 269
Cdd:cd05748    81 KV 82

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  77 PSAPLRLTLEDVSHSSLTVSWEPPEKLGKlGLQGYVLEFCREGASEWVPVNPRPVMVTQQTVRNLALGDKFFLRVTAVSS 156
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDGG-PITGYVVEYREKGSGDWKEVEVTPGSETSYTLTGLKPGTEYEFRVRAVNG 79

                  ....*..
gi 1274095709 157 AGAGPPA 163
Cdd:cd00063    80 GGESPPS 86

Immunoglobulin (Ig)-like domain of titin and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain found in titin-like proteins and similar proteins. Titin (also called connectin) is a fibrous sarcomeric protein specifically found in vertebrate striated muscle. Titin is a giant protein; depending on isoform composition, it ranges from 2970 to 3700 kDa, and is of a length that spans half a sarcomere. Titin largely consists of multiple repeats of Ig-like and fibronectin type 3 (FN-III)-like domains. Titin connects the ends of myosin thick filaments to Z disks and extends along the thick filament to the H zone. It appears to function similarly to an elastic band, keeping the myosin filaments centered in the sarcomere during muscle contraction or stretching. Within the sarcomere, titin is also attached to or is associated with myosin binding protein C (MyBP-C). MyBP-C appears to contribute to the generation of passive tension by titin and like titin has repeated Ig-like and FN-III domains. Also included in this group are worm twitchin and insect projectin, thick filament proteins of invertebrate muscle which also have repeated Ig-like and FN-III domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 189 TYIRQVGESVNLQIPFQGKPKPQVSWTHNGHALDN-QRVNVRSGDQDSILFIRSAQRADSGRYELTVHLEGLEAKASIDI 267
Cdd:cd05748     1 TIVVRAGESLRLDIPIKGRPTPTVTWSKDGQPLKEtGRVQIETTASSTSLVIKNAKRSDSGKYTLTLKNSAGEKSATINV 80

                  ..
gi 1274095709 268 LV 269
Cdd:cd05748    81 KV 82

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 1274095709 388 PSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQG---DPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAIN 464
Cdd:cd20951     1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPssiPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                          90
                  ....*....|....
gi 1274095709 465 VLGEASVDCRLEVK 478
Cdd:cd20951    81 IHGEASSSASVVVE 94

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 1274095709 193 QVGESVNLQIPFQGKPKPQVSWTHNGHAL-DNQRVNVRSGDQDSILFIRSAQRADSGRYELTVHLEGLEAKASI 265
Cdd:pfam07679  13 QEGESARFTCTVTGTPDPEVSWFKDGQPLrSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAGEAEASA 86

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 273 PGPPSSIKLLDVWGCNAALEWTPPQDTGnTELLGYTVQKADKRTGQWFTVLERYHPTT-CTISDLIIGNSYSFRVFSENL 351
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDG-GPITGYVVEYREKGSGDWKEVEVTPGSETsYTLTGLKPGTEYEFRVRAVNG 79

                          90
                  ....*....|
gi 1274095709 352 CGLSDLATTT 361
Cdd:cd00063    80 GGESPPSESV 89

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709   77 PSAPLRLTLEDVSHSSLTVSWEPPEKLGKLG-LQGYVLEFcREGASEWVPVNPRPVmVTQQTVRNLALGDKFFLRVTAVS 155
Cdd:smart00060   1 PSPPSNLRVTDVTSTSVTLSWEPPPDDGITGyIVGYRVEY-REEGSEWKEVNVTPS-STSYTLTGLKPGTEYEFRVRAVN 78

                   ....*
gi 1274095709  156 SAGAG 160
Cdd:smart00060  79 GAGEG 83

Fibronectin type III domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1274095709 274 GPPSSIKLLDVWGCNAALEWTPPqDTGNTELLGYTVQKADKRTGQ-WFTVLERYHPTTCTISDLIIGNSYSFRVFSEN 350
Cdd:pfam00041   1 SAPSNLTVTDVTSTSLTVSWTPP-PDGNGPITGYEVEYRPKNSGEpWNEITVPGTTTSVTLTGLKPGTEYEVRVQAVN 77

Fibronectin type 3 domain [General function prediction only];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  76 VPSAPLRLTLEDVSHSSLTVSWEPPEklgKLGLQGYVLEFCREGASEWVPVNprPVMVTQQTVRNLALGDKFFLRVTAVS 155
Cdd:COG3401   232 PPSAPTGLTATADTPGSVTLSWDPVT---ESDATGYRVYRSNSGDGPFTKVA--TVTTTSYTDTGLTNGTTYYYRVTAVD 306

                  ...
gi 1274095709 156 SAG 158
Cdd:COG3401   307 AAG 309

Fibronectin type 3 domain [General function prediction only];

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 249 RYELTVHLEGLEAKASIDILVI---EKPGPPSSIKLLDVWGCNAALEWTPPQDTGNTellGYTVQKADKRTGQWfTVLER 325
Cdd:COG3401   206 YYRVAATDTGGESAPSNEVSVTtptTPPSAPTGLTATADTPGSVTLSWDPVTESDAT---GYRVYRSNSGDGPF-TKVAT 281

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....
gi 1274095709 326 YHPTTCTISDLIIGNSYSFRVFSENLCG----LSDLATTTKELA 365
Cdd:COG3401   282 VTTTSYTDTGLTNGTTYYYRVTAVDAAGnesaPSNVVSVTTDLT 325

Immunoglobulin (Ig)-like domain of titin and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain found in titin-like proteins and similar proteins. Titin (also called connectin) is a fibrous sarcomeric protein specifically found in vertebrate striated muscle. Titin is a giant protein; depending on isoform composition, it ranges from 2970 to 3700 kDa, and is of a length that spans half a sarcomere. Titin largely consists of multiple repeats of Ig-like and fibronectin type 3 (FN-III)-like domains. Titin connects the ends of myosin thick filaments to Z disks and extends along the thick filament to the H zone. It appears to function similarly to an elastic band, keeping the myosin filaments centered in the sarcomere during muscle contraction or stretching. Within the sarcomere, titin is also attached to or is associated with myosin binding protein C (MyBP-C). MyBP-C appears to contribute to the generation of passive tension by titin and like titin has repeated Ig-like and FN-III domains. Also included in this group are worm twitchin and insect projectin, thick filament proteins of invertebrate muscle which also have repeated Ig-like and FN-III domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 189 TYIRQVGESVNLQIPFQGKPKPQVSWTHNGHALDN-QRVNVRSGDQDSILFIRSAQRADSGRYELTVHLEGLEAKASIDI 267
Cdd:cd05748     1 TIVVRAGESLRLDIPIKGRPTPTVTWSKDGQPLKEtGRVQIETTASSTSLVIKNAKRSDSGKYTLTLKNSAGEKSATINV 80

                  ..
gi 1274095709 268 LV 269
Cdd:cd05748    81 KV 82

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 1274095709 388 PSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQG---DPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAIN 464
Cdd:cd20951     1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVPIDPssiPGKYKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                          90
                  ....*....|....
gi 1274095709 465 VLGEASVDCRLEVK 478
Cdd:cd20951    81 IHGEASSSASVVVE 94

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  77 PSAPLRLTLEDVSHSSLTVSWEPPEKLGKlGLQGYVLEFCREGASEWVPVNPRPVMVTQQTVRNLALGDKFFLRVTAVSS 156
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDGG-PITGYVVEYREKGSGDWKEVEVTPGSETSYTLTGLKPGTEYEFRVRAVNG 79

                  ....*..
gi 1274095709 157 AGAGPPA 163
Cdd:cd00063    80 GGESPPS 86

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1274095709 388 PSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAIN 464
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  188 QTYIRQVGESVNLQIPFQGKPKPQVSWTHNGHAL--DNQRVNVRSGDQDSILFIRSAQRADSGRYELTVHLEGLEAKASI 265
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLlaESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGT 81

                   ....
gi 1274095709  266 DILV 269
Cdd:smart00410  82 TLTV 85

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 1274095709 388 PSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPK-YRAVSEQGVCTLEIRKPSPFDSGVYTCKAINVL 466
Cdd:cd20975     1 PTFKVSLMDQSVREGQDVIMSIRVQGEPKPVVSWLRNRQPVRPDQRrFAEEAEGGLCRLRILAAERGDAGFYTCKAVNEY 80

                          90
                  ....*....|.
gi 1274095709 467 GEASVDCRLEV 477
Cdd:cd20975    81 GARQCEARLEV 91

Fibronectin type 3 domain; One of three types of internal repeats found in the plasma protein fibronectin. Its tenth fibronectin type III repeat contains an RGD cell recognition sequence in a flexible loop between 2 strands. Approximately 2% of all animal proteins contain the FN3 repeat; including extracellular and intracellular proteins, membrane spanning cytokine receptors, growth hormone receptors, tyrosine phosphatase receptors, and adhesion molecules. FN3-like domains are also found in bacterial glycosyl hydrolases.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 273 PGPPSSIKLLDVWGCNAALEWTPPQDTGnTELLGYTVQKADKRTGQWFTVLERYHPTT-CTISDLIIGNSYSFRVFSENL 351
Cdd:cd00063     1 PSPPTNLRVTDVTSTSVTLSWTPPEDDG-GPITGYVVEYREKGSGDWKEVEVTPGSETsYTLTGLKPGTEYEFRVRAVNG 79

                          90
                  ....*....|
gi 1274095709 352 CGLSDLATTT 361
Cdd:cd00063    80 GGESPPSESV 89

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  396 DHTSTPGYSTQLFCSVRASPKPKIIWMKNKMD-IQGDPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAINVLGEASVDCR 474
Cdd:smart00410   3 SVTVKEGESVTLSCEASGSPPPEVTWYKQGGKlLAESGRFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTT 82

                   ...
gi 1274095709  475 LEV 477
Cdd:smart00410  83 LTV 85

Fibronectin type 3 domain; One of three types of internal repeat within the plasma protein, fibronectin. The tenth fibronectin type III repeat contains a RGD cell recognition sequence in a flexible loop between 2 strands. Type III modules are present in both extracellular and intracellular proteins.

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709  273 PGPPSSIKLLDVWGCNAALEWTPPQDTGNTE-LLGYTVQKADKrTGQWFTVLERYHPTTCTISDLIIGNSYSFRVFSENL 351
Cdd:smart00060   1 PSPPSNLRVTDVTSTSVTLSWEPPPDDGITGyIVGYRVEYREE-GSEWKEVNVTPSSTSYTLTGLKPGTEYEFRVRAVNG 79

                   ....
gi 1274095709  352 CGLS 355
Cdd:smart00060  80 AGEG 83

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 1274095709 387 APSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAINVL 466
Cdd:cd20972     1 PPQFIQKLRSQEVAEGSKVRLECRVTGNPTPVVRWFCEGKELQNSPDIQIHQEGDLHSLIIAEAFEEDTGRYSCLATNSV 80

                          90
                  ....*....|.
gi 1274095709 467 GEASVDCRLEV 477
Cdd:cd20972    81 GSDTTSAEIFV 91

Fibronectin type III domain;

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1274095709 274 GPPSSIKLLDVWGCNAALEWTPPqDTGNTELLGYTVQKADKRTGQ-WFTVLERYHPTTCTISDLIIGNSYSFRVFSEN 350
Cdd:pfam00041   1 SAPSNLTVTDVTSTSLTVSWTPP-PDGNGPITGYEVEYRPKNSGEpWNEITVPGTTTSVTLTGLKPGTEYEVRVQAVN 77

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
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1274095709 198 VNLQIPFQGKPKPQVSWTHNGHALDNQ-RVNVRSGDQDSILFIRSAQRADSGRYELTVH 255
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLPPSsRDSRRSELGNGTLTISNVTLEDSGTYTCVAS 59

Third 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 third 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 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, 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, and 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 Slit2 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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1274095709 395 ADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIqgdPKYRA-VSEQGvcTLEIRKPSPFDSGVYTCKAINVLGEASVDC 473
Cdd:cd05725     5 QNQVVLVDDSAEFQCEVGGDPVPTVRWRKEDGEL---PKGRYeILDDH--SLKIRKVTAGDMGSYTCVAENMVGKIEASA 79

                  ....
gi 1274095709 474 RLEV 477
Cdd:cd05725    80 TLTV 83

Immunoglobulin (Ig)-like domain of the human basement membrane heparan sulfate proteoglycan perlecan and similar proteins; The members here are composed of the immunoglobulin (Ig)-like domain of the human basement membrane heparan sulfate proteoglycan perlecan, also known as HSPG2, and similar proteins. Perlecan consists of five domains: domain I has three putative heparan sulfate attachment sites, domain II has four LDL receptor-like repeats, and one Ig-like repeat, domain III resembles the short arm of laminin chains, domain IV has multiple Ig-like repeats (21 repeats in human perlecan), and domain V resembles the globular G domain of the laminin A chain and internal repeats of EGF. Perlecan may participate in a variety of biological functions including cell binding, LDL-metabolism, basement membrane assembly and selective permeability, calcium binding, and growth- and neurite-promoting activities.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1274095709 402 GYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAINVLGE--ASVDCRLEV 477
Cdd:cd05743     1 GETVEFTCVATGVPTPIINWRLNWGHVPDSARVSITSEGGYGTLTIRDVKESDQGAYTCEAINTRGMvfGIPDGILTV 78

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

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gi 1274095709 390 FTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQG-DPKYRAVsEQGvcTLEIRKPSPFDSGVYTCKAINVLGE 468
Cdd:cd20952     2 ILQGPQNQTVAVGGTVVLNCQATGEPVPTISWLKDGVPLLGkDERITTL-ENG--SLQIKGAEKSDTGEYTCVALNLSGE 78

                  ....*....
gi 1274095709 469 ASVDCRLEV 477
Cdd:cd20952    79 ATWSAVLDV 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.

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                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1274095709 402 GYSTQLFCSVRASPKPKIIWM---KNKMDIQGDPKYRAVSEQgvcTLEIRKPSPFDSGVYTCKAINVLGEASVDCRLEV 477
Cdd:cd20969    17 GHTVQFVCRADGDPPPAILWLsprKHLVSAKSNGRLTVFPDG---TLEVRYAQVQDNGTYLCIAANAGGNDSMPAHLHV 92

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.

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gi 1274095709 384 FSEAPSFTqpladhTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRAVSEQGVCTLEIRKPSPFDSGVYTCKAI 463
Cdd:cd20949     2 FTENAYVT------TVKEGQSATILCEVKGEPQPNVTWHFNGQPISASVADMSKYRILADGLLINKVTQDDTGEYTCRAY 75

                  ....*..
gi 1274095709 464 NVLGEAS 470
Cdd:cd20949    76 QVNSIAS 82

Second 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.

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gi 1274095709 388 PSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRA-VSEQGVCTLEIRKPSPFDSGVYTCKAINVL 466
Cdd:cd20990     1 PHFLQAPGDLTVQEGKLCRMDCKVSGLPTPDLSWQLDGKPIRPDSAHKMlVRENGVHSLIIEPVTSRDAGIYTCIATNRA 80

                          90
                  ....*....|.
gi 1274095709 467 GEASVDCRLEV 477
Cdd:cd20990    81 GQNSFNLELVV 91

First immunoglobulin-like domains A168 within the A-band segment of human cardiac titin, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domain A168 within the A-band segment of human cardiac titin. 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 structures of the titin-A168169 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.

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gi 1274095709 387 APSFTQPLADHTSTPGYSTQLFCSVRASPKPKIIWMKNKMDIQGDPKYRAVSEQ-GVCTLEIRKPS-PFDSGVYTCKAIN 464
Cdd:cd20971     1 APHFKEELRNLNVRYQSNATLVCKVTGHPKPIVKWYRQGKEIIADGLKYRIQEFkGGYHQLIIASVtDDDATVYQVRATN 80

                  ....*.
gi 1274095709 465 VLGEAS 470
Cdd:cd20971    81 QGGSVS 86

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.

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gi 1274095709 388 PSFTQPLA----DHTSTPGYSTQLFCSVRASPKPKIIWMKN---KMDIQGDPKYRaVSEQGVcTLEIRKPSPFDSGVYTC 460
Cdd:cd05729     1 PRFTDTEKmeerEHALPAANKVRLECGAGGNPMPNITWLKDgkeFKKEHRIGGTK-VEEKGW-SLIIERAIPRDKGKYTC 78

                          90
                  ....*....|....*..
gi 1274095709 461 KAINVLGEASVDCRLEV 477
Cdd:cd05729    79 IVENEYGSINHTYDVDV 95

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.

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gi 1274095709 401 PGYSTQLFCSVRASPKPKIIWMKNKMDIQGD-PKYRAVSEQGvCTLEIRKPSPFDSGVYTCKAINVLG 467
Cdd:cd05736    14 PGVEASLRCHAEGIPLPRVQWLKNGMDINPKlSKQLTLIANG-SELHISNVRYEDTGAYTCIAKNEGG 80