Fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein (also known as Neph2). This protein has five Ig-like domains, one transmembrane domain, and a cytoplasmic tail. Included in this group is mammalian Kirrel (Neph1). These proteins contain multiple Ig domains, have properties of cell adhesion molecules, and are important in organ development. Neph1 and 2 may mediate axonal guidance and synapse formation in certain areas of the CNS. In the kidney they participate in the formation of the slit diaphragm.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 390 GPPTISSTQTQQVLYGEKGQIKCFIRSTPPPDRIAWSWKETVLESGTSGRYTVETVSTEEGVISTLTMSNIVPADFQTIY 469
Cdd:cd05898     1 GPPIISSEQVQYAVRGERGKVKCFIGSTPPPDRIAWAWKENVLESGTLERYTVERTSTGSGVLSTLTINNIMEADFQTHY 80

                          90
                  ....*....|....*...
gi 1678725515 470 NCTAWNSFGSDTEIIRLK 487
Cdd:cd05898    81 NCTAWNSFGSGTAIIQLE 98

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 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGS------GVVLSNKK---TLTLKAVKQEDAGKYVCRAVVPrV 377
Cdd:pfam07679   1 PKFTQKPKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQplrssdRFKVTYEGgtyTLTISNVQPDDSGKYTCVATNS-A 79

                          90
                  ....*....|.
gi 1678725515 378 GAGEKEVSLTV 388
Cdd:pfam07679  80 GEAEASAELTV 90

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 1678725515 222 PIVNLTVDPQPVLEGNLVKFHCAAKANPPVIfYRWAKGGHVILDVPGDTYEVLVDHTFFT-EPVS--------CEVTN 290
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPT-ITWYKNGEPISSGSTRSRSLSGSNSTLTiSNVTrsdagtytCVASN 78

Fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein (also known as Neph2). This protein has five Ig-like domains, one transmembrane domain, and a cytoplasmic tail. Included in this group is mammalian Kirrel (Neph1). These proteins contain multiple Ig domains, have properties of cell adhesion molecules, and are important in organ development. Neph1 and 2 may mediate axonal guidance and synapse formation in certain areas of the CNS. In the kidney they participate in the formation of the slit diaphragm.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 390 GPPTISSTQTQQVLYGEKGQIKCFIRSTPPPDRIAWSWKETVLESGTSGRYTVETVSTEEGVISTLTMSNIVPADFQTIY 469
Cdd:cd05898     1 GPPIISSEQVQYAVRGERGKVKCFIGSTPPPDRIAWAWKENVLESGTLERYTVERTSTGSGVLSTLTINNIMEADFQTHY 80

                          90
                  ....*....|....*...
gi 1678725515 470 NCTAWNSFGSDTEIIRLK 487
Cdd:cd05898    81 NCTAWNSFGSGTAIIQLE 98

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGS------GVVLSNKK---TLTLKAVKQEDAGKYVCRAVVPrV 377
Cdd:pfam07679   1 PKFTQKPKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQplrssdRFKVTYEGgtyTLTISNVQPDDSGKYTCVATNS-A 79

                          90
                  ....*....|.
gi 1678725515 378 GAGEKEVSLTV 388
Cdd:pfam07679  80 GEAEASAELTV 90

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  313 PQSLQVDQGSDAVFNCAWTGNPSLTIVWMK----------RGSGVVLSNKKTLTLKAVKQEDAGKYVCRAvVPRVGAGEK 382
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSPPPEVTWYKqggkllaesgRFSVSRSGSTSTLTISNVTPEDSGTYTCAA-TNSSGSASS 79

                   ....*.
gi 1678725515  383 EVSLTV 388
Cdd:smart00410  80 GTTLTV 85

CD80-like C2-set immunoglobulin domain; These domains belong to the immunoglobulin superfamily.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 122 PVIVGAPVMSLRAGDHLNLTCHADNAKPAASIIWIRNGLVLSGAMYSKTLLRDGKRESTVSTLYLSPSNIESGQQITCRA 201
Cdd:pfam08205   1 PTIEPPASLLEGEGPEVVATCSSAGGKPAPRITWYLDGKPLEAAETSSEQDPESGLVTVTSELKLVPSRSDHGQSLTCQV 80

                  ..
gi 1678725515 202 SN 203
Cdd:pfam08205  81 SY 82

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515   26 PTDLVVVAGQPVTLPCSIPGY-HGMVLWLRDGMALgvnrdLSGYPRYDIvgDHSKGEYHLLIQRTEIQDDAFFECQAIQA 104
Cdd:smart00410   1 PPSVTVKEGESVTLSCEASGSpPPEVTWYKQGGKL-----LAESGRFSV--SRSGSTSTLTISNVTPEDSGTYTCAATNS 73

                           90
                   ....*....|..
gi 1678725515  105 AI-RSRPARLTV 115
Cdd:smart00410  74 SGsASSGTTLTV 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  21 VFTQQPTDLVVVAGQPVTLPCSIPGY-HGMVLWLRDGMALGVNRDLSGYprydivgdHSKGEYHLLIQRTEIQDDAFFEC 99
Cdd:pfam13927   3 VITVSPSSVTVREGETVTLTCEATGSpPPTITWYKNGEPISSGSTRSRS--------LSGSNSTLTISNVTRSDAGTYTC 74

                  ..
gi 1678725515 100 QA 101
Cdd:pfam13927  75 VA 76

Fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3 protein (also known as Neph2). This protein has five Ig-like domains, one transmembrane domain, and a cytoplasmic tail. Included in this group is mammalian Kirrel (Neph1). These proteins contain multiple Ig domains, have properties of cell adhesion molecules, and are important in organ development. Neph1 and 2 may mediate axonal guidance and synapse formation in certain areas of the CNS. In the kidney they participate in the formation of the slit diaphragm.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 390 GPPTISSTQTQQVLYGEKGQIKCFIRSTPPPDRIAWSWKETVLESGTSGRYTVETVSTEEGVISTLTMSNIVPADFQTIY 469
Cdd:cd05898     1 GPPIISSEQVQYAVRGERGKVKCFIGSTPPPDRIAWAWKENVLESGTLERYTVERTSTGSGVLSTLTINNIMEADFQTHY 80

                          90
                  ....*....|....*...
gi 1678725515 470 NCTAWNSFGSDTEIIRLK 487
Cdd:cd05898    81 NCTAWNSFGSGTAIIQLE 98

Second immunoglobulin (Ig)-like domain of Kirrel (kin of irregular chiasm-like) 3, 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 of Kirrel (kin of irregular chiasm-like) 3 (also known as Neph2). This protein has five Ig-like domains, one transmembrane domain, and a cytoplasmic tail. Included in this group is mammalian Kirrel (Neph1), Kirrel2 (Neph3), and Drosophila RST (irregular chiasm C-roughest) protein. These proteins contain multiple Ig domains, have properties of cell adhesion molecules, and are important in organ development.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 121 DPVIVGAPVMSLRAGDHLNLTCHADNAKPAASIIWIRNGLVLSGAMYSKTLLRDGKRESTVSTLYLSPSNIESGQQITCR 200
Cdd:cd05759     1 DPVIEGGPVISLQAGVPYNLTCRARGAKPAAEIIWFRDGEQLEGAVYSKELLKDGKRETTVSTLLITPSDLDTGRTFTCR 80

                          90
                  ....*....|....*...
gi 1678725515 201 ASNKAAPNGKDASVTIDI 218
Cdd:cd05759    81 ARNEAIPNGKETSITLDV 98

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 1678725515 313 PQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRG------SGVVLSNKKTLTLKAVKQEDAGKYVC 370
Cdd:cd20957     8 PPVQTVDFGRTAVFNCSVTGNPIHTVLWMKDGkplghsSRVQILSEDVLVIPSVKREDKGMYQC 71

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRG---------SGVVLSNKKTLTLKAVKQEDAGKYVCRA 372
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGepissgstrSRSLSGSNSTLTISNVTRSDAGTYTCVA 76

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 324 AVFNCAWTGNPSLTIVWMKRGSGV---------VLSNKKTLTLKAVKQEDAGKYVCRAVVPRVGAGEKEV 384
Cdd:cd00096     1 VTLTCSASGNPPPTITWYKNGKPLppssrdsrrSELGNGTLTISNVTLEDSGTYTCVASNSAGGSASASV 70

Second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 - Necl-4; member of the I-set of Ig superfamily domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the nectin-like molecules Necl-1 (also known as cell adhesion molecule 3 or CADM3), Necl-2 (also known as CADM1), Necl-3 (also known as CADM2) and Necl-4 (also known as CADM4). These nectin-like molecules have similar domain structures to those of nectins. At least five nectin-like molecules have been identified (Necl-1 through Necl-5). These have an extracellular region containing three Ig-like domains, one transmembrane region, and one cytoplasmic region. The N-terminal Ig-like domain of the extracellular region belongs to the V-type subfamily of Ig domains, is essential to cell-cell adhesion, and plays a part in the interaction with the envelope glycoprotein D of various viruses. Necl-1 and Necl-2 have Ca(2+)-independent homophilic and heterophilic cell-cell adhesion activity. Necl-1 is specifically expressed in neural tissue and is important to the formation of synapses, axon bundles, and myelinated axons. Necl-2 is expressed in a wide variety of tissues, and is a putative tumour suppressor gene, which is downregulated in aggressive neuroblastoma. Necl-3 has been shown to accumulate in tissues of the central and peripheral nervous system, where it is expressed in ependymal cells and myelinated axons. It is observed at the interface between the axon shaft and the myelin sheath. Necl-4 is expressed on Schwann cells, and plays a key part in initiating peripheral nervous system (PNS) myelination. Necl-4 participates in cell-cell adhesion and is proposed to play a role in tumor suppression.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 116 LVPPDDPVIVG--APVMSlraGDHLNLTCHADNAKPAASIIWIRNGLVLSGAMYSKTllRDGKRESTV-STLYLSPSNIE 192
Cdd:cd05761     1 LGVPEKPVITGftSPVVE---GDEITLTCTTSGSKPAADIRWFKNDKELKGVKEVQE--SGAGKTFTVtSTLRFRVDRDD 75

                          90
                  ....*....|....*..
gi 1678725515 193 SGQQITCRASNKAAPNG 209
Cdd:cd05761    76 DGVAVICRVDHESLTST 92

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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  24 QQPTDLVVVAGQPVTLPCSIPGYH--GMVLWLRDGMALgvnrDLSGyPRYDIVGDHSkgeyhLLIQRTEIQDDAFFECQA 101
Cdd:cd05724     2 VEPSDTQVAVGEMAVLECSPPRGHpePTVSWRKDGQPL----NLDN-ERVRIVDDGN-----LLIAEARKSDEGTYKCVA 71

                          90
                  ....*....|....*.
gi 1678725515 102 --IQAAIRSRPARLTV 115
Cdd:cd05724    72 tnMVGERESRAARLSV 87

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 1678725515 312 EPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGVVLSNKK-------TLTLKAVKQEDAGKYVCravVPRVGAGEKEV 384
Cdd:cd20952     5 GPQNQTVAVGGTVVLNCQATGEPVPTISWLKDGVPLLGKDERittlengSLQIKGAEKSDTGEYTC---VALNLSGEATW 81

                  ....
gi 1678725515 385 SLTV 388
Cdd:cd20952    82 SAVL 85

Fourth immunoglobulin (Ig)-like domain in Robo (roundabout) receptors; member of the I-set of Ig superfamily (IgSF) domains; Members here are composed the fourth 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1678725515 312 EPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGVVL--------------SNKKTLTLKAVKQEDAGKYVCRAV 373
Cdd:cd05726     5 KPRDQVVALGRTVTFQCETKGNPQPAIFWQKEGSQNLLfpyqppqpssrfsvSPTGDLTITNVQRSDVGYYICQAL 80

Immunoglobulin (Ig)-like domain of human titin C terminus and similar proteins; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the fifth immunoglobulin (Ig)-like domain from the C-terminus of human titin x and similar proteins. Titin (also called connectin) is a fibrous sarcomeric protein specifically found in vertebrate striated muscle. Titin is gigantic; 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 and appears to function similar to an elastic band, keeping the myosin filaments centered in the sarcomere during muscle contraction or stretching. 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 1678725515 308 RMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGVVLSN---------KKTLTLKAVKQEDAGKYvcrAVVPRVG 378
Cdd:cd05747     5 TILTKPRSLTVSEGESARFSCDVDGEPAPTVTWMREGQIIVSSQrhqitsteyKSTFEISKVQMSDEGNY---TVVVENS 81

                          90
                  ....*....|
gi 1678725515 379 AGEKEVSLTV 388
Cdd:cd05747    82 EGKQEAQFTL 91

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1678725515 321 GSDAVFNCAWTGNPSLTIVWMKRGSGVVLS----NKK---TLTLKAVKQEDAGKYVCRaVVPRVGA 379
Cdd:cd05856    19 GSSVRLKCVASGNPRPDITWLKDNKPLTPPeigeNKKkkwTLSLKNLKPEDSGKYTCH-VSNRAGE 83

First 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 first 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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  22 FTQQPTDLVVVAGQPVTLPCSIPGYHGMVL-WLRDGMALgvnrDLSGYPRYDIVGDHSkgeyhLLIQ-----RTEIQDDA 95
Cdd:cd05722     4 FLSEPSDIVAMRGGPVVLNCSAESDPPPKIeWKKDGVLL----NLVSDERRQQLPNGS-----LLITsvvhsKHNKPDEG 74

                          90       100
                  ....*....|....*....|...
gi 1678725515  96 FFECQA---IQAAIRSRPARLTV 115
Cdd:cd05722    75 FYQCVAqneSLGSIVSRTARVTV 97

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 1678725515 312 EPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGVVLS-----NKKTLTLKAVKQEDAGKYVCRAvVPRVGAGEKEVSL 386
Cdd:cd05725     3 RPQNQVVLVDDSAEFQCEVGGDPVPTVRWRKEDGELPKGryeilDDHSLKIRKVTAGDMGSYTCVA-ENMVGKIEASATL 81

                  ..
gi 1678725515 387 TV 388
Cdd:cd05725    82 TV 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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGV------------VLSNKKTLTLKAV----KQEDAGKYVC 370
Cdd:cd07693     1 PRIVEHPSDLIVSKGDPATLNCKAEGRPTPTIQWLKNGQPLetdkddprshriVLPSGSLFFLRVVhgrkGRSDEGVYVC 80

                  ..
gi 1678725515 371 RA 372
Cdd:cd07693    81 VA 82

Immunoglobulin (Ig)-like domain found in Perlecan and similar proteins; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig)-like domain found in Perlecan. Perlecan is a large multi-domain heparin sulfate proteoglycan, important in tissue development and organogenesis. Perlecan can be represented as 5 major portions; its fourth major portion (domain IV) is a tandem repeat of immunoglobulin-like domains (Ig2-Ig15) which can vary in size due to alternative splicing. Perlecan binds many cellular and extracellular ligands. Its domain IV region has many binding sites. Some of these have been mapped at the level of individual Ig-like domains, including a site restricted to the Ig5 domain for heparin/sulfatide, a site restricted to the Ig3 domain for nidogen-1 and nidogen-2, a site restricted to Ig4-5 for fibronectin, and sites restricted to Ig2 and to Ig13-15 for fibulin-2. 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 1678725515 312 EPQSLQVDQGSDAVFNC-AWTGNPSLTIVWmKRGSGVVLSNKK----TLTLKAVKQEDAGKYVC 370
Cdd:cd05754     7 EPRSQEVRPGADVSFICrAKSKSPAYTLVW-TRVNGTLPSRAMdfngILTIRNVQLSDAGTYVC 69

Immunoglobulin domain; This domain contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 307 PRMAAEPQslQVDQGSDAVFNCAWTGNPSLTIVWMKRGSgvVLSNKKTLTLKAVKQEDAGKYVCRAVVPRVGAGEKEVSL 386
Cdd:pfam13895   2 PVLTPSPT--VVTEGEPVTLTCSAPGNPPPSYTWYKDGS--AISSSPNFFTLSVSAEDSGTYTCVARNGRGGKVSNPVEL 77

                  ..
gi 1678725515 387 TV 388
Cdd:pfam13895  78 TV 79

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 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGSGVVLSNKKT--------LTLKAVKQEDAGKYVCRAvVPRVG 378
Cdd:cd20976     2 PSFSSVPKDLEAVEGQDFVAQCSARGKPVPRITWIRNAQPLQYAADRStceagvgeLHIQDVLPEDHGTYTCLA-KNAAG 80

                          90
                  ....*....|
gi 1678725515 379 AGEKEVSLTV 388
Cdd:cd20976    81 QVSCSAWVTV 90

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  21 VFTQQPTDLVVVAGQPVTLPCSIPGY-HGMVLWLRDGMALGVNRDLSGYprydivgdHSKGEYHLLIQRTEIQDDAFFEC 99
Cdd:pfam13927   3 VITVSPSSVTVREGETVTLTCEATGSpPPTITWYKNGEPISSGSTRSRS--------LSGSNSTLTISNVTRSDAGTYTC 74

                  ..
gi 1678725515 100 QA 101
Cdd:pfam13927  75 VA 76

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  21 VFTQQPTDLVVVAGQPVTLPCSIPGYHGM-VLWLRDGmalgvnRDLSGYPRYDIvgDHSKGEYHLLIQRTEIQDDAFFEC 99
Cdd:pfam07679   2 KFTQKPKDVEVQEGESARFTCTVTGTPDPeVSWFKDG------QPLRSSDRFKV--TYEGGTYTLTISNVQPDDSGKYTC 73

                  ..
gi 1678725515 100 QA 101
Cdd:pfam07679  74 VA 75

Seventh immunoglobulin domain of the Drosophila melanogaster Dscam protein, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the seventh 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. This group 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.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515  25 QPTDLVVVAGQPVTLPCSIPGY-HGMVLWLRD-GMALGVNRDLSGYPRYDIVGDHSkgeyhLLIQRTEIQDDAFFECQAI 102
Cdd:cd20954     7 EPVDANVAAGQDVMLHCQADGFpTPTVTWKKAtGSTPGEYKDLLYDPNVRILPNGT-----LVFGHVQKENEGHYLCEAK 81

Immunoglobulin (Ig)-like domain of Down Syndrome Cell Adhesion molecule (DSCAM); The members here are composed of the immunoglobulin (Ig)-like domain of Down Syndrome Cell Adhesion molecule (DSCAM). DSCAM is a cell adhesion molecule expressed largely in the developing nervous system. The gene encoding DSCAM is located at human chromosome 21q22, the locus associated with the intellectual disability phenotype of Down Syndrome. DSCAM is predicted to be the largest member of the IG superfamily. It has been demonstrated that DSCAM can mediate cation-independent homophilic intercellular adhesion.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 307 PRMAAEPQSLQVDQGSDAVFNCAWTGNPSLTIVW-MKRGSGV--------------VLSNkKTLTLKAVKQEDAGKYVCR 371
Cdd:cd05734     2 PRFVVQPNDQDGIYGKAVVLNCSADGYPPPTIVWkHSKGSGVpqfqhivplngriqLLSN-GSLLIKHVLEEDSGYYLCK 80

                  .
gi 1678725515 372 A 372
Cdd:cd05734    81 V 81

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

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1678725515 396 STQTQQVLyGEKGQIKCFIRSTPPPdRIAWSWKETVLeSGTSGRYTVETvsteegviSTLTMSNIVPADFQTiYNCTAWN 475
Cdd:cd20978     8 EKNVVVKG-GQDVTLPCQVTGVPQP-KITWLHNGKPL-QGPMERATVED--------GTLTIINVQPEDTGY-YGCVATN 75

                  ...
gi 1678725515 476 SFG 478
Cdd:cd20978    76 EIG 78

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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 1678725515 312 EPQSLQVDQGSDAVFNCAWTGNPSLTIVWMKRGS--------GVVLSNKKTLTLKAVKQEDAGKYVCRA 372
Cdd:cd04978     5 EPPSLVLSPGETGELICEAEGNPQPTITWRLNGVpiepapedMRRTVDGRTLIFSNLQPNDTAVYQCNA 73