Kazal type serine protease inhibitors and follistatin-like domains. Kazal inhibitors inhibit serine proteases, such as, trypsin, chyomotrypsin, avian ovomucoids, and elastases. The inhibitory domain has one reactive site peptide bond, which serves the cognate enzyme as substrate. The reactive site peptide bond is a combining loop which has an identical conformation in all Kazal inhibitors and in all enzyme/inhibitor complexes. These Kazal domains (small hydrophobic core of alpha/beta structure with 3 to 4 disulfide bonds) often occur in tandem arrays. Similar domains are also present in follistatin (FS) and follistatin-like family members, which play an important role in tissue specific regulation. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a Kazal-like domain and has five disulfide bonds. Although the Kazal-like FS substructure is similar to Kazal proteinase inhibitors, no FS domain has yet been shown to be a proteinase inhibitor. Follistatin-like family members include SPARC, also known as, BM-40 or osteonectin, the Gallus gallus Flik protein, as well as, agrin which has a long array of FS domains. The kazal-type inhibitor domain has also been detected in an extracellular loop region of solute carrier 21 (SLC21) family members (organic anion transporters) , which may regulate the specificity of anion uptake. The distant homolog, Ascidian trypsin inhibitor, is included in this CD.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 767935631  93 CRPSYVPVCGSDGRFYENHCKLHRAACLLGKRITVIHSKDC 133
Cdd:cd00104    1 CPKEYDPVCGSDGKTYSNECHLGCAACRSGRSITVAHNGPC 41

DNA-binding beta-propeller fold protein YncE [General function prediction only];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 511 NRYIYVAQPALSRVLVVDIQAQKVLQSIGVDPLPAKLSYDKSHDQVWVLSWGD--VHK-SRPSLQVITEASTGQSqhlir 587
Cdd:COG3391   79 GRRLYVANSGSGRVSVIDLATGKVVATIPVGGGPRGLAVDPDGGRLYVADSGNgrVSViDTATGKVVATIPVGAG----- 153

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 588 tpfagvddffipPTNLIIN-HIRFGFIFNKSDPAVHKV----DLETMMPLKTIGLHHHgcvPQAMAHTHLGGYFFIQCRQ 662
Cdd:COG3391  154 ------------PHGIAVDpDGKRLYVANSGSNTVSVIvsviDTATGKVVATIPVGGG---PVGVAVSPDGRRLYVANRG 218

                 .
gi 767935631 663 D 663
Cdd:COG3391  219 S 219

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 767935631  340 PPVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKN 417
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Kazal type serine protease inhibitors and follistatin-like domains. Kazal inhibitors inhibit serine proteases, such as, trypsin, chyomotrypsin, avian ovomucoids, and elastases. The inhibitory domain has one reactive site peptide bond, which serves the cognate enzyme as substrate. The reactive site peptide bond is a combining loop which has an identical conformation in all Kazal inhibitors and in all enzyme/inhibitor complexes. These Kazal domains (small hydrophobic core of alpha/beta structure with 3 to 4 disulfide bonds) often occur in tandem arrays. Similar domains are also present in follistatin (FS) and follistatin-like family members, which play an important role in tissue specific regulation. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a Kazal-like domain and has five disulfide bonds. Although the Kazal-like FS substructure is similar to Kazal proteinase inhibitors, no FS domain has yet been shown to be a proteinase inhibitor. Follistatin-like family members include SPARC, also known as, BM-40 or osteonectin, the Gallus gallus Flik protein, as well as, agrin which has a long array of FS domains. The kazal-type inhibitor domain has also been detected in an extracellular loop region of solute carrier 21 (SLC21) family members (organic anion transporters) , which may regulate the specificity of anion uptake. The distant homolog, Ascidian trypsin inhibitor, is included in this CD.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 767935631  93 CRPSYVPVCGSDGRFYENHCKLHRAACLLGKRITVIHSKDC 133
Cdd:cd00104    1 CPKEYDPVCGSDGKTYSNECHLGCAACRSGRSITVAHNGPC 41

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 767935631  256 SVTTVTVGLSTVLTCAVHGDLRPPIIWKRNGLTLNFLDLEDINDFGEDDSLYITKVTTIHMGNYTCHAS 324
Cdd:pfam13927   9 SSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVAS 77

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631   256 SVTTVTVGLSTVLTCAVHGDLRPPIIWKRNGLTL-----NFLDLEDINDFgeddSLYITKVTTIHMGNYTCHAS-GHEQL 329
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLlaesgRFSVSRSGSTS----TLTISNVTPEDSGTYTCAATnSSGSA 77

                   ....*...
gi 767935631   330 FQTHVLQV 337
Cdd:smart00410  78 SSGTTLTV 85

DNA-binding beta-propeller fold protein YncE [General function prediction only];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 511 NRYIYVAQPALSRVLVVDIQAQKVLQSIGVDPLPAKLSYDKSHDQVWVLSWGD--VHK-SRPSLQVITEASTGQSqhlir 587
Cdd:COG3391   79 GRRLYVANSGSGRVSVIDLATGKVVATIPVGGGPRGLAVDPDGGRLYVADSGNgrVSViDTATGKVVATIPVGAG----- 153

                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 588 tpfagvddffipPTNLIIN-HIRFGFIFNKSDPAVHKV----DLETMMPLKTIGLHHHgcvPQAMAHTHLGGYFFIQCRQ 662
Cdd:COG3391  154 ------------PHGIAVDpDGKRLYVANSGSNTVSVIvsviDTATGKVVATIPVGGG---PVGVAVSPDGRRLYVANRG 218

                 .
gi 767935631 663 D 663
Cdd:COG3391  219 S 219

Ca2+-binding protein, EF-hand superfamily [Signal transduction mechanisms];

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 179 VESLFRDLDADGNGHLSSSELAQhVLKKQDLDEDllgcSPGDLLRFDDYNSDSSLTLREF 238
Cdd:COG5126   71 ARAAFDLLDTDGDGKISADEFRR-LLTALGVSEE----EADELFARLDTDGDGKISFEEF 125

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 767935631  340 PPVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKN 417
Cdd:pfam13927   1 KPVITVSPSSVTVREGETVTLTCEATGSPPPTITWYKNGEPISSGSTRSRSLSGSNSTLTISNVTRSDAGTYTCVASN 78

Immunoglobulin I-set domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631  341 PVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNEVG 420
Cdd:pfam07679   1 PKFTQKPKDVEVQEGESARFTCTVTGTPDPEVSWFKDGQPLRSSDRFKVTYEGGTYTLTISNVQPDDSGKYTCVATNSAG 80

                          90
                  ....*....|
gi 767935631  421 VDEDISSLFI 430
Cdd:pfam07679  81 EAEASAELTV 90

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 767935631 340 PPVIRVYPESQAQEpGVAASLRCHAEGIPMPRITWLKNGVDVsTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNEV 419
Cdd:cd20976    2 PSFSSVPKDLEAVE-GQDFVAQCSARGKPVPRITWIRNAQPL-QYAADRSTCEAGVGELHIQDVLPEDHGTYTCLAKNAA 79

                 ..
gi 767935631 420 GV 421
Cdd:cd20976   80 GQ 81

agrin-responsive first immunoglobulin-like domains (Ig1) of the MuSK ectodomain; a member of the I-set of IgSF domains; The members here are composed of the first immunoglobulin-like domains (Ig1) of the Muscle-specific kinase (MuSK). MuSK is a receptor tyrosine kinase specifically expressed in skeletal muscle, where it plays a central role in the formation and maintenance of the neuromuscular junction (NMJ). MuSK is activated by agrin, a neuron-derived heparan sulfate proteoglycan. The activation of MUSK in myotubes regulates the formation of NMJs through the regulation of different processes including the specific expression of genes in subsynaptic nuclei, the reorganization of the actin cytoskeleton and the clustering of the acetylcholine receptors (AChR) in the postsynaptic membrane. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the MuSK lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 767935631 355 GVAASLRCHAEGIPMPRITWLKNGVDVSTqMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNEVG 420
Cdd:cd20970   17 GENATFMCRAEGSPEPEISWTRNGNLIIE-FNTRYIVRENGTTLTIRNIRRSDMGIYLCIASNGVP 81

Kazal type serine protease inhibitors and follistatin-like domains. Kazal inhibitors inhibit serine proteases, such as, trypsin, chyomotrypsin, avian ovomucoids, and elastases. The inhibitory domain has one reactive site peptide bond, which serves the cognate enzyme as substrate. The reactive site peptide bond is a combining loop which has an identical conformation in all Kazal inhibitors and in all enzyme/inhibitor complexes. These Kazal domains (small hydrophobic core of alpha/beta structure with 3 to 4 disulfide bonds) often occur in tandem arrays. Similar domains are also present in follistatin (FS) and follistatin-like family members, which play an important role in tissue specific regulation. The FS domain consists of an N-terminal beta hairpin (FOLN/EGF-like domain) and a Kazal-like domain and has five disulfide bonds. Although the Kazal-like FS substructure is similar to Kazal proteinase inhibitors, no FS domain has yet been shown to be a proteinase inhibitor. Follistatin-like family members include SPARC, also known as, BM-40 or osteonectin, the Gallus gallus Flik protein, as well as, agrin which has a long array of FS domains. The kazal-type inhibitor domain has also been detected in an extracellular loop region of solute carrier 21 (SLC21) family members (organic anion transporters) , which may regulate the specificity of anion uptake. The distant homolog, Ascidian trypsin inhibitor, is included in this CD.

                         10        20        30        40
                 ....*....|....*....|....*....|....*....|.
gi 767935631  93 CRPSYVPVCGSDGRFYENHCKLHRAACLLGKRITVIHSKDC 133
Cdd:cd00104    1 CPKEYDPVCGSDGKTYSNECHLGCAACRSGRSITVAHNGPC 41

Third immunoglobulin (Ig)-like domain of Neural Cell Adhesion Molecule 1 (NCAM-1); member of the I-set of IgSF domains; The members here are composed of the third immunoglobulin (Ig)-like domain of Neural Cell Adhesion Molecule (NCAM-1). NCAM plays important roles in the development and regeneration of the central nervous system, in synaptogenesis and neural migration. NCAM mediates cell-cell and cell-substratum recognition and adhesion via homophilic (NCAM-NCAM), and heterophilic (NCAM-non-NCAM), interactions. NCAM is expressed as three major isoforms having different intracellular extensions. The extracellular portion of NCAM has five N-terminal Ig-like domains and two fibronectin type III domains. The double zipper adhesion complex model for NCAM homophilic binding involves Ig1, Ig2, and Ig3. By this model, Ig1 and Ig2 mediate dimerization of NCAM molecules situated on the same cell surface (cis interactions), and Ig3 domains mediate interactions between NCAM molecules expressed on the surface of opposing cells (trans interactions) through binding to the Ig1 and Ig2 domains. The adhesive ability of NCAM is modulated by the addition of polysialic acid chains to the fifth Ig-like domain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 340 PPVIRVypeSQAQ-----EPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKqLSLLANGSELHISSVRYEDTGAYTCI 414
Cdd:cd05730    1 PPTIRA---RQSEvnataNLGQSVTLACDADGFPEPTMTWTKDGEPIESGEEK-YSFNEDGSEMTILDVDKLDEAEYTCI 76

                         90
                 ....*....|....
gi 767935631 415 AKNEVGVDEDISSL 428
Cdd:cd05730   77 AENKAGEQEAEIHL 90

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 341 PVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKNGV--DVSTQMSK-QLSLLANGSELHISSVRYEDTGAYTCIAKN 417
Cdd:cd20951    1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYKNGVpiDPSSIPGKyKIESEYGVHVLHIRRVTVEDSAVYSAVAKN 80

                 ....
gi 767935631 418 EVGV 421
Cdd:cd20951   81 IHGE 84

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 349 SQAQEPGVAASLRCHAEGI-PMPRITWLKNGVDVSTQMSKQLSLLAN--GSELHISSVRYEDTGAYTCIAKNEVGVDEDI 425
Cdd:cd05750    8 SQTVQEGSKLVLKCEATSEnPSPRYRWFKDGKELNRKRPKNIKIRNKkkNSELQINKAKLEDSGEYTCVVENILGKDTVT 87

                 ....*
gi 767935631 426 SSLFI 430
Cdd:cd05750   88 GNVTV 92

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 340 PPVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKngvdVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNEV 419
Cdd:cd04968    1 PSIKVRFPADTYALKGQTVTLECFALGNPVPQIKWRK----VDGSPSSQWEITTSEPVLEIPNVQFEDEGTYECEAENSR 76

                 ...
gi 767935631 420 GVD 422
Cdd:cd04968   77 GKD 79

Immunoglobulin (Ig)-like I-set domain of Neural Cell Adhesion Molecule 1 (NCAM-1) and similar proteins; The members here are composed of the fourth immunoglobulin (Ig)-like domain of Neural Cell Adhesion Molecule (NCAM-1). NCAM plays important roles in the development and regeneration of the central nervous system, in synaptogenesis and neural migration. NCAM mediates cell-cell and cell-substratum recognition and adhesion via homophilic (NCAM-NCAM), and heterophilic (NCAM-non-NCAM), interactions. NCAM is expressed as three major isoforms having different intracellular extensions. The extracellular portion of NCAM has five N-terminal Ig-like domains and two fibronectin type III domains. The double zipper adhesion complex model for NCAM homophilic binding involves Ig1, Ig2, and Ig3. By this model, Ig1 and Ig2 mediate dimerization of NCAM molecules situated on the same cell surface (cis interactions), and Ig3 domains mediate interactions between NCAM molecules expressed on the surface of opposing cells (trans interactions), through binding to the Ig1 and Ig2 domains. The adhesive ability of NCAM is modulated by the addition of polysialic acid chains to the fifth Ig-like domain. Also included in this group is NCAM-2 (also known as OCAM/mamFas II and RNCAM) NCAM-2 is differentially expressed in the developing and mature olfactory epithelium (OE). One of the unique features of I-set domains is the lack of a C" strand. The structures of this group show that the Ig domain lacks this strand and thus is a member of the I-set of Ig domains.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 339 VPPVIrVYPESQAQEPGVAASLRCHAEGIPMPRITWlKNGVDVSTQMSKQLS------LLANGSELHISSVRYEDTGAYT 412
Cdd:cd05732    1 VQPKI-TYLENQTAVELEQITLTCEAEGDPIPEITW-RRATRGISFEEGDLDgrivvrGHARVSSLTLKDVQLTDAGRYD 78

                         90
                 ....*....|....*....
gi 767935631 413 CIAKNEVGVdeDISSLFIE 431
Cdd:cd05732   79 CEASNRIGG--DQQSMYLE 95

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 767935631 355 GVAASLRCHAEGIPMPRITWLKN-GVDVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNEVG 420
Cdd:cd05763   14 GSTARLECAATGHPTPQIAWQKDgGTDFPAARERRMHVMPEDDVFFIVDVKIEDTGVYSCTAQNSAG 80

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 767935631 360 LRCHAEGIPMPRITWLKNGVDVSTQMSKqlSLLANGSeLHISSVRYEDTGAYTCIAKNEVG 420
Cdd:cd20978   21 LPCQVTGVPQPKITWLHNGKPLQGPMER--ATVEDGT-LTIINVQPEDTGYYGCVATNEIG 78

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 767935631 339 VPPVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSELHISSVRYEDTGAYTCIAKNE 418
Cdd:cd05747    2 LPATILTKPRSLTVSEGESARFSCDVDGEPAPTVTWMREGQIIVSSQRHQITSTEYKSTFEISKVQMSDEGNYTVVVENS 81

                 ....*
gi 767935631 419 VGVDE 423
Cdd:cd05747   82 EGKQE 86

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 767935631 347 PESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSeLHISSVRYEDTGAYTCIAKNEVG 420
Cdd:cd05867    6 PQSHLYGPGETARLDCQVEGIPTPNITWSINGAPIEGTDPDPRRHVSSGA-LILTDVQPSDTAVYQCEARNRHG 78

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 767935631 355 GVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGSELhISSVRYE-----DTGAYTCIAKNE 418
Cdd:cd05722   16 GGPVVLNCSAESDPPPKIEWKKDGVLLNLVSDERRQQLPNGSLL-ITSVVHSkhnkpDEGFYQCVAQNE 83

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 355 GVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLANGS-ELHISSVRYEDTGAYTCIAKNEVGVDE 423
Cdd:cd05744   15 GRLCRFDCKVSGLPTPDLFWQLNGKPVRPDSAHKMLVRENGRhSLIIEPVTKRDAGIYTCIARNRAGENS 84

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 767935631 344 RVYPESQAQEPGVAASLRCHA-EGIPMPRITWLKNGVDVSTQmSKQLSLLANGSeLHISSVRYEDTGAYTCIAKNEVGVD 422
Cdd:cd05724    1 RVEPSDTQVAVGEMAVLECSPpRGHPEPTVSWRKDGQPLNLD-NERVRIVDDGN-LLIAEARKSDEGTYKCVATNMVGER 78

                 .
gi 767935631 423 E 423
Cdd:cd05724   79 E 79

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 767935631 355 GVAASLRCHAEGIPMPRITWLKNG--VDVSTQMSKQLSLLANGseLHISSVRYEDTGAYTCIAKNEVGVDEDISSL 428
Cdd:cd20949   14 GQSATILCEVKGEPQPNVTWHFNGqpISASVADMSKYRILADG--LLINKVTQDDTGEYTCRAYQVNSIASDMQER 87

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631   256 SVTTVTVGLSTVLTCAVHGDLRPPIIWKRNGLTL-----NFLDLEDINDFgeddSLYITKVTTIHMGNYTCHAS-GHEQL 329
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGGKLlaesgRFSVSRSGSTS----TLTISNVTPEDSGTYTCAATnSSGSA 77

                   ....*...
gi 767935631   330 FQTHVLQV 337
Cdd:smart00410  78 SSGTTLTV 85

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 767935631 341 PVIRVYPESQAQEpgvAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLSLLanGSELHISS-VRYEDTGAYTCIAKNEV 419
Cdd:cd04967    8 PDDTIFPEDSDEK---KVALNCRARANPVPSYRWLMNGTEIDLESDYRYSLV--DGTLVISNpSKAKDAGHYQCLATNTV 82

                 .
gi 767935631 420 G 420
Cdd:cd04967   83 G 83

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 767935631 347 PESQAQEPGVAASLRCHAEGIPMPRITWLKNGVDVSTQMSKQLsllaNGSELHISSVRYEDTGAYTCIAKNEVGVDEDIS 426
Cdd:cd05725    4 PQNQVVLVDDSAEFQCEVGGDPVPTVRWRKEDGELPKGRYEIL----DDHSLKIRKVTAGDMGSYTCVAENMVGKIEASA 79

                 ..
gi 767935631 427 SL 428
Cdd:cd05725   80 TL 81

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

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 767935631 360 LRCHAEGIPMPRITWLKNGVDVSTqmSKQLSLLANGSeLHISSVRYEDTGAYTCIAKNEVG 420
Cdd:cd05746    3 IPCSAQGDPEPTITWNKDGVQVTE--SGKFHISPEGY-LAIRDVGVADQGRYECVARNTIG 60

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 767935631 258 TTVTVGLSTVLTCAVHGDLRPPIIWKRNGLTLNFLDLEDIndfgEDDSLYITKVTTIHMGNYTCHA 323
Cdd:cd05725    7 QVVLVDDSAEFQCEVGGDPVPTVRWRKEDGELPKGRYEIL----DDHSLKIRKVTAGDMGSYTCVA 68

Third immunoglobulin-like domain of the human WFIKKN (WAP, follistatin, immunoglobulin, Kunitz and NTR domain-containing protein), and similar domains; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin-like domain of the human WFIKKN (WAP, follistatin, immunoglobulin, Kunitz and NTR domain-containing protein) and similar proteins. WFIKKN is a secreted protein that consists of multiple types of protease inhibitory modules, including two tandem Kunitz-type protease inhibitor-domains. The Ig superfamily is a heterogenous group of proteins built on a common fold comprised of a sandwich of two beta sheets. Members of the Ig superfamily are components of immunoglobulin, neuroglia, cell surface glycoproteins, such as T-cell receptors, CD2, CD4, CD8, and membrane glycoproteins, such as 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. 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 767935631 341 PVIRVYPESQAQEPGVAASLRCHAEGIPMPRITWLK------NGVDVSTQMSKQLsLLANGSELHISSVRYEDTGAYTCI 414
Cdd:cd05765    1 PALVNSPTHQTVKVGETASFHCDVTGRPQPEITWEKqvpgkeNLIMRPNHVRGNV-VVTNIGQLVIYNAQPQDAGLYTCT 79

                 ....*..
gi 767935631 415 AKNEVGV 421
Cdd:cd05765   80 ARNSGGL 86