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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 283436190    47 EAGHPISLSClSAFGTPSPLYYWYKIEGNTIVP---VKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLT 122
Cdd:smart00410   7 KEGESVTLSC-EASGSPPPEVTWYKQGGKLLAEsgrFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLT 84

Procyclic acidic repetitive protein (PARP); This family consists of several Trypanosoma brucei procyclic acidic repetitive protein (PARP) like sequences. The procyclic acidic repetitive protein (parp) genes of Trypanosoma brucei encode a small family of abundant surface proteins whose expression is restricted to the procyclic form of the parasite. They are found at two unlinked loci, parpA and parpB; transcription of both loci is developmentally regulated.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 283436190  207 EPTTTAVLEPEYEPNPPLETTTQPDPEPEgsvPVLAPEAEIQPHPE 252
Cdd:pfam05887  68 EPEPEPEPEPEPEPEPEPEPEPEPEPEPE---PEPEPEPEPEPEPE 110

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 283436190    47 EAGHPISLSClSAFGTPSPLYYWYKIEGNTIVP---VKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLT 122
Cdd:smart00410   7 KEGESVTLSC-EASGSPPPEVTWYKQGGKLLAEsgrFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLT 84

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 283436190  49 GHPISLSCLsAFGTPSPLYYWYKIEGNTI--VPVKESFNTAtgvLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLT 122
Cdd:cd05731   10 GGVLLLECI-AEGLPTPDIRWIKLGGELPkgRTKFENFNKT---LKIENVSEADSGEYQCTASNTMGSARHTISVT 81

Procyclic acidic repetitive protein (PARP); This family consists of several Trypanosoma brucei procyclic acidic repetitive protein (PARP) like sequences. The procyclic acidic repetitive protein (parp) genes of Trypanosoma brucei encode a small family of abundant surface proteins whose expression is restricted to the procyclic form of the parasite. They are found at two unlinked loci, parpA and parpB; transcription of both loci is developmentally regulated.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 283436190  207 EPTTTAVLEPEYEPNPPLETTTQPDPEPEgsvPVLAPEAEIQPHPE 252
Cdd:pfam05887  68 EPEPEPEPEPEPEPEPEPEPEPEPEPEPE---PEPEPEPEPEPEPE 110

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

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 283436190    47 EAGHPISLSClSAFGTPSPLYYWYKIEGNTIVP---VKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLT 122
Cdd:smart00410   7 KEGESVTLSC-EASGSPPPEVTWYKQGGKLLAEsgrFSVSRSGSTSTLTISNVTPEDSGTYTCAATNSSGSASSGTTLT 84

Third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM), and similar domains; The members here are composed of the third immunoglobulin (Ig)-like domain of the L1 cell adhesion molecule (CAM). L1 belongs to the L1 subfamily of cell adhesion molecules (CAMs) and is comprised of an extracellular region having six Ig-like domains and five fibronectin type III domains, a transmembrane region and an intracellular domain. L1 is primarily expressed in the nervous system and is involved in its development and function. L1 is associated with an X-linked recessive disorder, X-linked hydrocephalus, MASA syndrome, and spastic paraplegia type 1, that involves abnormalities of axonal growth. This group also contains the chicken neuron-glia cell adhesion molecule, Ng-CAM and human neurofascin.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 283436190  49 GHPISLSCLsAFGTPSPLYYWYKIEGNTI--VPVKESFNTAtgvLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLT 122
Cdd:cd05731   10 GGVLLLECI-AEGLPTPDIRWIKLGGELPkgRTKFENFNKT---LKIENVSEADSGEYQCTASNTMGSARHTISVT 81

Immunoglobulin (Ig)-like domain of protein zero (P0) and similar proteins; The members here are composed of the immunoglobulin (Ig) domain of protein zero (P0), a myelin membrane adhesion molecule. P0 accounts for over 50% of the total protein in peripheral nervous system (PNS) myelin. P0 is a single-pass transmembrane glycoprotein with a highly basic intracellular domain and an extracellular Ig domain. The extracellular domain of P0 (P0-ED) is similar to the Ig variable domain, carrying one acceptor sequence for N-linked glycosylation. P0 plays a role in membrane adhesion in the spiral wraps of the myelin sheath. The intracellular domain is thought to mediate membrane apposition of the cytoplasmic faces and may, through electrostatic interactions, interact directly with lipid headgroups. It is thought that homophilic interactions of the P0 extracellular domain mediate membrane juxtaposition in the extracellular space of PNS myelin. This group also contains the Ig domain of sodium channel subunit beta-2 (SCN2B), and of epithelial V-like antigen 1 (EVA). EVA, also known as myelin protein zero-like 2, is an adhesion molecule, which may play a role in structural organization of the thymus and early lymphocyte development. SCN2B subunits play a role in determining sodium channel density and function in neurons,and in control of electrical excitability in the brain.

                         10        20
                 ....*....|....*....|..
gi 283436190   1 MQPADSGIYICDVNNPPDFVGK 22
Cdd:cd05715   88 LQFSDNGTYTCDVKNPPDIVGG 109

Second Ig-like domain of Junctional adhesion molecule-1 (JAM1); a member of the I-set of IgSF domains; The members here are composed of the second Ig-like domain of Junctional adhesion molecule-1 (JAM1). JAM1 is an immunoglobulin superfamily (IgSF) protein with two Ig-like domains in its extracellular region; it plays a role in the formation of endothelial and epithelial tight junction and acts as a receptor for mammalian reovirus sigma-1. The 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 second Ig-like domain of JAM1 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, the A strand of the I-set is discontinuous but lacks 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 283436190  38 PFCTIQGRPEAGHPISLSCLSAFGTPSPLYYWYKieGNTIVPVKE-----------SFNTATGVLVIGNLTNFEQGYYQC 106
Cdd:cd20950    1 PTVNIPSSATIGNRAVLTCSEPDGSPPSEYTWFK--DGVVMPTNPkstrafsnssySLDPTTGELVFDPLSASDTGEYSC 78

                 ....*..
gi 283436190 107 TAINSLG 113
Cdd:cd20950   79 EARNGYG 85

Procyclic acidic repetitive protein (PARP); This family consists of several Trypanosoma brucei procyclic acidic repetitive protein (PARP) like sequences. The procyclic acidic repetitive protein (parp) genes of Trypanosoma brucei encode a small family of abundant surface proteins whose expression is restricted to the procyclic form of the parasite. They are found at two unlinked loci, parpA and parpB; transcription of both loci is developmentally regulated.

                          10        20        30        40
                  ....*....|....*....|....*....|....*....|....*.
gi 283436190  207 EPTTTAVLEPEYEPNPPLETTTQPDPEPEgsvPVLAPEAEIQPHPE 252
Cdd:pfam05887  68 EPEPEPEPEPEPEPEPEPEPEPEPEPEPE---PEPEPEPEPEPEPE 110

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 283436190  61 GTPSPLYYWyKIEGNTIVPVKESF----NTATGVLVIGNLTNFEQGYYQCTAINSLGNSSCEIDL 121
Cdd:cd05744   26 GLPTPDLFW-QLNGKPVRPDSAHKmlvrENGRHSLIIEPVTKRDAGIYTCIARNRAGENSFNAEL 89

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

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 283436190  47 EAGHPISLSCLSAFGTPSPLYYWYKiEGNTI-----VPVKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSS 116
Cdd:cd05750   12 QEGSKLVLKCEATSENPSPRYRWFK-DGKELnrkrpKNIKIRNKKKNSELQINKAKLEDSGEYTCVVENILGKDT 85

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 283436190  48 AGHPISLSClSAFGTPSPLYYWYKiEGNTIVPVKESFNT-ATGVLVIGNLTNFEQGYYQCTAINSLGNSS 116
Cdd:cd20952   13 VGGTVVLNC-QATGEPVPTISWLK-DGVPLLGKDERITTlENGSLQIKGAEKSDTGEYTCVALNLSGEAT 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        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 283436190  49 GHPISLSClSAFGTPSPLYYWYKiEGNTIVPVKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSSCEIDLTS 123
Cdd:cd20978   16 GQDVTLPC-QVTGVPQPKITWLH-NGKPLQGPMERATVEDGTLTIINVQPEDTGYYGCVATNEIGDIYTETLLHV 88

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

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 283436190  49 GHPISLSCLSAfGTPSPLYYWYKiEGNtivPVKESFNTATG-------VLVIGNLTNFEQGYYQCTAINSLGNSSCEIDL 121
Cdd:cd20973   12 GSAARFDCKVE-GYPDPEVKWMK-DDN---PIVESRRFQIDqdedglcSLIISDVCGDDSGKYTCKAVNSLGEATCSAEL 86

                 .
gi 283436190 122 T 122
Cdd:cd20973   87 T 87

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
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 283436190  47 EAGHPISLSClSAFGTPSPLYYWYKIEGNTIVPVKESFNTAT------GVLVIGNLTNFEQGYYQCTAINSLG 113
Cdd:cd20954   14 AAGQDVMLHC-QADGFPTPTVTWKKATGSTPGEYKDLLYDPNvrilpnGTLVFGHVQKENEGHYLCEAKNGIG 85

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.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....
gi 283436190  49 GHPISLSClSAFGTPSPLYYWYKIEgnTIVPVKESFNTATG------VLVIGNLTNFEQGYYQCTAINSLGNSS 116
Cdd:cd20971   16 QSNATLVC-KVTGHPKPIVKWYRQG--KEIIADGLKYRIQEfkggyhQLIIASVTDDDATVYQVRATNQGGSVS 86

Fifth immunoglobulin (Ig) domain of contactin; The members here are composed of the fifth 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.

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*.
gi 283436190  61 GTPSPLYYWYKiEGNTIVPVKESFNTATGVLVIGNLTNFEQGYYQCTAINSLGNSS 116
Cdd:cd04969   28 ASPKPTISWSK-GTELLTNSSRICILPDGSLKIKNVTKSDEGKYTCFAVNFFGKAN 82