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

                          10        20        30        40        50
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1720430630  51 LQCNLTSSSHTLMYSyWTRNGVELTAT-------RKNASNMEYRINKPRAEDSGEYHCV 102
Cdd:cd05750    19 LKCEATSENPSPRYR-WFKDGKELNRKrpknikiRNKKKNSELQINKAKLEDSGEYTCV 76

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630  128 RSENKNEGQDAMMYCKSVGYPHPEWIWRKKENgvfeEISNSSGRFFITNKENYTELSIVNLQiTEDPGEYECNATNSIGS 207
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGG----KLLAESGRFSVSRSGSTSTLTISNVT-PEDSGTYTCAATNSSGS 76

                   ....*....
gi 1720430630  208 ASVSTVLRV 216
Cdd:smart00410  77 ASSGTTLTV 85

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
                  ....*....|....*....|....*....|....*....|....*....|....*....
gi 1720430630  51 LQCNLTSSSHTLMYSyWTRNGVELTAT-------RKNASNMEYRINKPRAEDSGEYHCV 102
Cdd:cd05750    19 LKCEATSENPSPRYR-WFKDGKELNRKrpknikiRNKKKNSELQINKAKLEDSGEYTCV 76

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 1720430630  32 PRIVTSEEVIIRESLLPVTLQCNLTSSSHTLMYsyWTRNGVELT-----ATRKNASNMEYRINKPRAEDSGEYHCV 102
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPTIT--WYKNGEPISsgstrSRSLSGSNSTLTISNVTRSDAGTYTCV 75

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

                           10        20        30        40        50        60        70        80
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630  128 RSENKNEGQDAMMYCKSVGYPHPEWIWRKKENgvfeEISNSSGRFFITNKENYTELSIVNLQiTEDPGEYECNATNSIGS 207
Cdd:smart00410   2 PSVTVKEGESVTLSCEASGSPPPEVTWYKQGG----KLLAESGRFSVSRSGSTSTLTISNVT-PEDSGTYTCAATNSSGS 76

                   ....*....
gi 1720430630  208 ASVSTVLRV 216
Cdd:smart00410  77 ASSGTTLTV 85

Immunoglobulin domain; This family contains immunoglobulin-like domains.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 121 PDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKkeNGvfEEISNSSGRFFITNKENYTeLSIVNLQiTEDPGEYECN 200
Cdd:pfam13927   2 PVITVSPSSVTVREGETVTLTCEATGSPPPTITWYK--NG--EPISSGSTRSRSLSGSNST-LTISNVT-RSDAGTYTCV 75

                  ...
gi 1720430630 201 ATN 203
Cdd:pfam13927  76 ASN 78

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 1720430630 119 AAPDITgHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKENGVFEEISNSSGRFFITNKENYTELSIVNLQITeDPGEYE 198
Cdd:cd05732     1 VQPKIT-YLENQTAVELEQITLTCEAEGDPIPEITWRRATRGISFEEGDLDGRIVVRGHARVSSLTLKDVQLT-DAGRYD 78

                          90
                  ....*....|....*...
gi 1720430630 199 CNATNSIGSASVSTVLRV 216
Cdd:cd05732    79 CEASNRIGGDQQSMYLEV 96

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 1720430630 121 PDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKkeNGVFEEISNSSGRFFITNKENYTELsIVNLQITEDPGEYECN 200
Cdd:cd20951     1 PEFIIRLQSHTVWEKSDAKLRVEVQGKPDPEVKWYK--NGVPIDPSSIPGKYKIESEYGVHVL-HIRRVTVEDSAVYSAV 77

                          90
                  ....*....|....*..
gi 1720430630 201 ATNSIGSASVSTVLRVR 217
Cdd:cd20951    78 AKNIHGEASSSASVVVE 94

Immunoglobulin (Ig)-like I-set domain of Neural Cell Adhesion Molecule 2 (NCAM-2); The members here are composed of the fourth Ig domain of Neural Cell Adhesion Molecule NCAM-2 (also known as OCAM/mamFas II and RNCAM). NCAM-2 is organized similarly to NCAM, including five N-terminal Ig-like domains and two fibronectin type III domains. NCAM-2 is differentially expressed in the developing and mature olfactory epithelium (OE), and may function like NCAM, as an adhesion molecule. 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 1720430630 121 PDITgHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKENGV-FEEISNS-SGRFFITNKENYTELSIVNLQITeDPGEYE 198
Cdd:cd05870     3 PHII-QLKNETTVENGAATLSCKAEGEPIPEITWKRASDGHtFSEGDKSpDGRIEVKGQHGESSLHIKDVKLS-DSGRYD 80

                          90
                  ....*....|....*...
gi 1720430630 199 CNATNSIGSASVSTVLRV 216
Cdd:cd05870    81 CEAASRIGGHQKSMYLDI 98

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 1720430630 135 GQDAMMYCKSVGYPHPEWIWRKKENGVFEEISNSSGRFFITNKENYTeLSIVNLQiTEDPGEYECNATNSIGS 207
Cdd:cd20954    16 GQDVMLHCQADGFPTPTVTWKKATGSTPGEYKDLLYDPNVRILPNGT-LVFGHVQ-KENEGHYLCEAKNGIGS 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        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 127 KRSENKNEGQDAMMYCKSVGYPHPEWIWRKKEngvfeEISNSSGRFFITNKENyteLSIVNLQiTEDPGEYECNATNSIG 206
Cdd:cd04969     9 KKKILAAKGGDVIIECKPKASPKPTISWSKGT-----ELLTNSSRICILPDGS---LKIKNVT-KSDEGKYTCFAVNFFG 79

                          90
                  ....*....|
gi 1720430630 207 SASVSTVLRV 216
Cdd:cd04969    80 KANSTGSLSV 89

Immunoglobulin (Ig)-like I-set domain of Neural Cell Adhesion Molecule 1 (NCAM-1); The members here are composed of the fourth Ig domain of Neural Cell Adhesion Molecule 1(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. 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 1720430630 119 AAPDITghkRSENKN--EGQDAM-MYCKSVGYPHPEWIWRKKENGVFEEISNSSGRFFITNKENYTELSIVNLQITeDPG 195
Cdd:cd05869     1 AKPKIT---YVENQTamELEEQItLTCEASGDPIPSITWRTSTRNISSEEKTLDGHIVVRSHARVSSLTLKYIQYT-DAG 76

                          90       100
                  ....*....|....*....|.
gi 1720430630 196 EYECNATNSIGSASVSTVLRV 216
Cdd:cd05869    77 EYLCTASNTIGQDSQSMYLEV 97

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        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 121 PDITGHKRSENKN--EGQDAMMYCKSVGYPHPEWIWRKKENGVFEEISNSSGRffitnkENYTELSIVNLQiTEDPGEYE 198
Cdd:cd20970     1 PVISTPQPSFTVTarEGENATFMCRAEGSPEPEISWTRNGNLIIEFNTRYIVR------ENGTTLTIRNIR-RSDMGIYL 73

                          90
                  ....*....|....*....
gi 1720430630 199 CNATNSI-GSASVSTVLRV 216
Cdd:cd20970    74 CIASNGVpGSVEKRITLQV 92

Second Ig-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk, and similar domains; a member of the I-set of IgSF domains; The members here are composed of the second immunoglobulin (Ig)-like domain of the giant muscle protein titin Z1z2 in the sarcomeric Z-disk and similar proteins. Titin is a key component in the assembly and functioning of vertebrate striated muscles. By providing connections at the level of individual microfilaments, it contributes to the fine balance of forces between the two halves of the sarcomere. The Ig superfamily (IgSF) is a heterogenous group of proteins, built on a common fold comprised of a sandwich of two beta sheets. IgSF domains can be divided into 4 main classes based on their structures and sequences: the Variable (V), Constant 1 (C1), Constant 2 (C2), and Intermediate (I) sets. Unlike the V-set, one of the distinctive features of I-set domains is the lack of a C" strand. The structure of the titin Z1z2 lacks this strand and thus it belongs to the I-set of the IgSF. I-set domains are found in several cell adhesion molecules (such as VCAM, ICAM, and MADCAM), and are also present in numerous other diverse protein families, including several tyrosine-protein kinase receptors, the hemolymph protein hemolin, the muscle proteins titin, telokin, and twitchin, the neuronal adhesion molecule axonin-1, and the signaling molecule semaphorin 4D that is involved in axonal guidance, immune function and angiogenesis.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 120 APDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKEngvfEEISNSSGrFFITNKENYTELsIVNLQITEDPGEYEC 199
Cdd:cd20972     1 PPQFIQKLRSQEVAEGSKVRLECRVTGNPTPVVRWFCEG----KELQNSPD-IQIHQEGDLHSL-IIAEAFEEDTGRYSC 74

                          90
                  ....*....|....*..
gi 1720430630 200 NATNSIGSASVSTVLRV 216
Cdd:cd20972    75 LATNSVGSDTTSAEIFV 91

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

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|..
gi 1720430630 145 VGYPHPEWIWrKKENGVFEEisnsSGRFFITNKENYTELSIVNLQiTEDPGEYECNATNSIGSASVSTVLRV 216
Cdd:cd05748    17 KGRPTPTVTW-SKDGQPLKE----TGRVQIETTASSTSLVIKNAK-RSDSGKYTLTLKNSAGEKSATINVKV 82

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 1720430630 128 RSENKNEGQDAMMYCKSVG-YPHPEWIWRKKENgvfeEISNS-SGRFFITNKENYTELSIvNLQITEDPGEYECNATNSI 205
Cdd:cd05750     7 KSQTVQEGSKLVLKCEATSeNPSPRYRWFKDGK----ELNRKrPKNIKIRNKKKNSELQI-NKAKLEDSGEYTCVVENIL 81

                          90
                  ....*....|.
gi 1720430630 206 GSASVSTVLRV 216
Cdd:cd05750    82 GKDTVTGNVTV 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
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 1720430630 135 GQDAMMYCKS-VGYPHPEWIWRKkeNGVFEEISNssgrffitnkENYTELSIVNLQITE----DPGEYECNATNSIG 206
Cdd:cd05724    12 GEMAVLECSPpRGHPEPTVSWRK--DGQPLNLDN----------ERVRIVDDGNLLIAEarksDEGTYKCVATNMVG 76

Fourth Ig domain of the neural cell adhesion molecule contactin-2, and similar domains; The members here are composed of the fourth Ig domain of the neural cell adhesion molecule contactin-2. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-2 (also called TAG-1, axonin-1) facilitates cell adhesion by homophilic binding between molecules in apposed membranes. The first four Ig domains form the intermolecular binding fragment which arranges as a compact U-shaped module by contacts between Ig domains 1 and 4, and domains 2 and 3. It has been proposed that a linear zipper-like array forms, from contactin-2 molecules alternatively provided by the two apposed membranes.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 1720430630 142 CKSVGYPHPEWIWRKkeNGvfeEISNSSGRFFITNKEnyteLSIVNLQItEDPGEYECNATNSIGSASVSTVLRV 216
Cdd:cd05728    21 CKASGNPRPAYRWLK--NG---QPLASENRIEVEAGD----LRITKLSL-SDSGMYQCVAENKHGTIYASAELAV 85

Immunoglobulin domain of human Synaptic Adhesion-Like Molecule 5 (SALM5) and similar proteins; member of the I-set of IgSF domains; This group contains the immunoglobulin domain of human Synaptic Adhesion-Like Molecule 5 (SALM5) and similar proteins. The SALM (for synaptic adhesion-like molecules; also known as Lrfn for leucine-rich repeat and fibronectin type III domain containing) family of adhesion molecules consists of five known members: SALM1/Lrfn2, SALM2/Lrfn1, SALM3/Lrfn4, SALM4/Lrfn3, and SALM5/Lrfn5. SALMs share a similar domain structure, containing leucine-rich repeats (LRRs), an immunoglobulin (Ig) domain, and a fibronectin III (FNIII) domain, followed by a transmembrane domain and a C-terminal PDZ-binding motif. SALM5 is implicated in autism spectrum disorders (ASDs) and schizophrenia, induces presynaptic differentiation in contacting axons. SALM5 interacts with the Ig domains of LAR (Leukocyte common Antigen-Related) family receptor protein tyrosine phosphatases (LAR-RPTPs; LAR, PTPdelta, and PTPsigma). In addition, PTPdelta is implicated in ASDs, ADHD, bipolar disorder, and restless leg syndrome. Studies have shown that LAR-RPTPs are novel and splicing-dependent presynaptic ligands for SALM5, and that they mediate SALM5-dependent presynaptic differentiation. Furthermore, SALM5 maintains AMPA receptor (AMPAR)-mediated excitatory synaptic transmission through mechanisms involving the interaction of SALM5 with LAR-RPTPs. This group belongs to the I-set of immunoglobulin superfamily (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 1720430630 121 PDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKENGVfeeISNSSGRFFITNKenytELSIvNLQITEDPGEYECN 200
Cdd:cd05764     1 PLITRHTHELRVLEGQRATLRCKARGDPEPAIHWISPEGKL---ISNSSRTLVYDNG----TLDI-LITTVKDTGAFTCI 72

                          90
                  ....*....|....*.
gi 1720430630 201 ATNSIGSASVSTVLRV 216
Cdd:cd05764    73 ASNPAGEATARVELHI 88

Sixth immunoglobulin (Ig) domain of contactin-2; The members here are composed of the sixth immunoglobulin (Ig) domain of the neural cell adhesion molecule contactin-2-like. Contactins are comprised of six Ig domains followed by four fibronectin type III (FnIII) domains anchored to the membrane by glycosylphosphatidylinositol. Contactin-2 (TAG-1, axonin-1) facilitates cell adhesion by homophilic binding between molecules in apposed membranes. It may play a part in the neuronal processes of neurite outgrowth, axon guidance and fasciculation, and neuronal migration. The first four Ig domains form the intermolecular binding fragment, which arranges as a compact U-shaped module by contacts between IG domains 1 and 4, and domains 2 and 3. 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-2 is also expressed in retinal amacrine cells (AC) in the developing chick retina, corresponding to the period of formation and maturation of AC processes.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 120 APDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKENGVFEEISNSSGRFFITN-KENYTELSIVNLQITEDpGEYE 198
Cdd:cd05854     2 ATKITLAPSSADINQGENLTLQCHASHDPTMDLTFTWSLDDFPIDLDKPNGHYRRMEvKETIGDLVIVNAQLSHA-GTYT 80

                          90
                  ....*....|....*....
gi 1720430630 199 CNATNSIGSASVSTVLRVR 217
Cdd:cd05854    81 CTAQTVVDSASASATLVVR 99

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

                           10        20        30        40        50        60
                   ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 1720430630   48 PVTLQCNLTSSSHTLMYsyWTRNGVELTAT------RKNASNMEYRINKPRAEDSGEYHCV 102
Cdd:smart00410  11 SVTLSCEASGSPPPEVT--WYKQGGKLLAEsgrfsvSRSGSTSTLTISNVTPEDSGTYTCA 69

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        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 135 GQDAMMYCKSVGYPHPEWIWRKK--ENGVFEEIS-NSSGRFFITNKenyTELSIVNLQITeDPGEYECNATNSIGSASVS 211
Cdd:cd05726    14 GRTVTFQCETKGNPQPAIFWQKEgsQNLLFPYQPpQPSSRFSVSPT---GDLTITNVQRS-DVGYYICQALNVAGSILAK 89

                  ....*
gi 1720430630 212 TVLRV 216
Cdd:cd05726    90 AQLEV 94

Second immunoglobulin (Ig)-like domain of a Follistatin-related protein 5, and similar domains; member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the second immunoglobulin (Ig)-like domain found in human Follistatin-related protein 5 (FSTL5) and a follistatin-like molecule encoded by the CNS-related Mahya gene. Mahya genes have been retained in certain Bilaterian branches during evolution. They are conserved in Hymenoptera and Deuterostomes, but are absent from other metazoan species such as fruit fly and nematode. Mahya proteins are secretory, with a follistatin-like domain (Kazal-type serine/threonine protease inhibitor domain and EF-hand calcium-binding domain), two Ig-like domains, and a novel C-terminal domain. Mahya may be involved in learning and memory and in processing of sensory information in Hymenoptera and vertebrates. Follistatin is a secreted, multidomain protein that binds activins with high affinity and antagonizes their signaling.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 121 PDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKKENGVFEEISNSsgrffITNKENYTELSIVNLQItEDPGEYECN 200
Cdd:cd05736     1 PVIRVYPEFQAKEPGVEASLRCHAEGIPLPRVQWLKNGMDINPKLSKQ-----LTLIANGSELHISNVRY-EDTGAYTCI 74

                  ....*.
gi 1720430630 201 ATNSIG 206
Cdd:cd05736    75 AKNEGG 80

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 1720430630 134 EGQDAMMYCKSVGYPHPEWIWRKkeNGvfEEISNSSGRFFITNKENYTELsiVNLQITEDPGEYECNATNSIGSAS 209
Cdd:cd20949    13 EGQSATILCEVKGEPQPNVTWHF--NG--QPISASVADMSKYRILADGLL--INKVTQDDTGEYTCRAYQVNSIAS 82

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 1720430630 120 APDITGHKRSENKNEGQDAMMYCKSVGYPHPEWIWRKkengVFEEISNSSGRFfiTNKENYTELSIVNLqITEDPGEYEC 199
Cdd:cd20976     1 APSFSSVPKDLEAVEGQDFVAQCSARGKPVPRITWIR----NAQPLQYAADRS--TCEAGVGELHIQDV-LPEDHGTYTC 73

                          90
                  ....*....|....*..
gi 1720430630 200 NATNSIGSASVSTVLRV 216
Cdd:cd20976    74 LAKNAAGQVSCSAWVTV 90

Third immunoglobulin (Ig)-like domain of fibroblast growth factor receptor 2 (FGFR2); member of the I-set of Ig superfamily (IgSF) domains; The members here are composed of the third immunoglobulin (Ig)-like domain of human fibroblast growth factor receptor 2 (FGFR2). Fibroblast growth factors (FGFs) participate in morphogenesis, development, angiogenesis, and wound healing. These FGF-stimulated processes are mediated by four FGFR tyrosine kinases (FGRF1-4). FGFRs are comprised of an extracellular portion consisting of three Ig-like domains, a transmembrane helix, and a cytoplasmic portion having protein tyrosine kinase activity. The highly conserved Ig-like domains 2 and 3, and the linker region between D2 and D3 define a general binding site for FGFs. FGFR2 is required for male sex determination. 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 1720430630 135 GQDAMMYCK--SVGYPHPEWIWRKKENGV--------FEEISNSSGrFFITNKEnyteLSIVNLQ-IT-EDPGEYECNAT 202
Cdd:cd05858    16 GTDAEFVCKvySDAQPHIQWLKHVEKNGSkygpdglpYVEVLKTAG-VNTTDKE----IEVLYLRnVTfEDAGEYTCLAG 90

                          90
                  ....*....|....
gi 1720430630 203 NSIGSASVSTVLRV 216
Cdd:cd05858    91 NSIGISHHSAWLTV 104

Fourth 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 fourth 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 1720430630 135 GQDAMMYCKSVGYPHPEWIWRKKENGVFEeisnsSGRF----FITnkENYTELSIVNlqIT----EDPGEYECNATNSIG 206
Cdd:cd20956    16 GPSVSLKCVASGNPLPQITWTLDGFPIPE-----SPRFrvgdYVT--SDGDVVSYVN--ISsvrvEDGGEYTCTATNDVG 86

                          90
                  ....*....|
gi 1720430630 207 SASVSTVLRV 216
Cdd:cd20956    87 SVSHSARINV 96

Immunoglobulin-like Ig0 domain of basigin-1 (BSG1) and similar proteins; The members here are composed of the immunoglobulin (Ig) domain of the collagenase stimulatory factor, basigin-1 (BSG1; also known as Cluster of Differentiation 147 (CD147) and Extracellular Matrix Metalloproteinase Inducer (EMMPRIN)) and similar proteins. CD147 is a transmembrane glycoprotein that belongs to the immunoglobulin superfamily. It is expressed in nearly all cells including platelets and fibroblasts and is involved in inflammatory diseases, and cancer progression. CD147 is highly expressed in several cancers and used as a prognostic marker. The two primary isoforms of CD147 that are related to cancer progression have been identified: CD147 Ig1-Ig2 (also called Basigin-2) that is ubiquitously expressed in most tissues and CD147 Ig0-Ig1-Ig2 (also called Basigin-1) that is retinal specific and implicated in retinoblastoma. Studies showed that CD147 Ig0 domain is a potent stimulator of interleukin-6 and suggest that the CD147 Ig0 dimer is the functional unit required for activity.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 129 SENKNEGQDAMMYCKSVGYPHPEWIWRKKENGVFEEISN-----SSGRFFIT---NKENYTELSIVNLqITEDPGEYECN 200
Cdd:cd20940     9 SQQRLVGDSVELHCEAVGSPIPEIQWWFEGQEPNEICSQlwdgaRLDRVHINatyHQHATSTISIDNL-TEEDTGTYECR 87

                          90
                  ....*....|....*..
gi 1720430630 201 ATNSIGSASVSTVLRVR 217
Cdd:cd20940    88 ASNDPDRNHLTRAPKVK 104

First immunoglobulin (Ig)-like domain of neural cell adhesion molecule NCAM-1, 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 of neural cell adhesion molecule NCAM-1. NCAM-1 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-nonNCAM) 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 the Ig1, Ig2, and Ig3 domains. 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). 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 1720430630 135 GQDAMMYCKSVGypHPEWIWRKKENGvfEEISNSSGRFFITNKEN-YTELSIVNLQItEDPGEYECNATNSIGSASVSTV 213
Cdd:cd04977    15 GESKFFLCKVSG--DAKNINWVSPNG--EKVLTKHGNLKVVNHGSvLSSLTIYNANI-NDAGIYKCVATNGKGTESEATV 89

Immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1; The members here are composed of the immunoglobulin (Ig)-like domain found in neuregulin (NRG)-1. There are many NRG-1 isoforms which arise from the alternative splicing of mRNA. NRG-1 belongs to the neuregulin gene family which is comprised of four genes. This group represents NRG-1. NRGs are signaling molecules which participate in cell-cell interactions in the nervous system, breast, and heart, and other organ systems, and are implicated in the pathology of diseases including schizophrenia, multiple sclerosis, and breast cancer. The NRG-1 protein binds to and activates the tyrosine kinases receptors ErbB3 and ErbB4, initiating signaling cascades. NRG-1 has multiple functions, for example, in the brain it regulates various processes such as radial glia formation and neuronal migration, dendritic development, and expression of neurotransmitters receptors in the peripheral nervous system NRG-1 regulates processes such as target cell differentiation, and Schwann cell survival.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1720430630 128 RSENKNEGQDAMMYCKSVG-YPHPEWIWRKKENGVFEEisNSSGRFFITNKENYTELSIvNLQITEDPGEYECNATNSIG 206
Cdd:cd05895     7 KSQEVAAGSKLVLRCETSSeYPSLRFKWFKNGKEINRK--NKPENIKIQKKKKKSELRI-NKASLADSGEYMCKVSSKLG 83

                  ....*
gi 1720430630 207 SASVS 211
Cdd:cd05895    84 NDSAS 88