CAP/Ponsin may exist as thirteen alternatively-spliced isoforms, ranging from 81 kDa to 142 kDa.[4] CAP/Ponsin is part of an adaptor protein family, of which ArgBP2 and vinexin are also a part.[5] These proteins contain a conserved sorbin homology (SOHO) domain and three SH3 domains, and CAP/Ponsin is expressed in heart, skeletal muscle, liver, adipose tissue, and macrophages.[4][6][7]
Function
In muscle, CAP/Ponsin plays a role in the formation of mature costameres from focal adhesion-like contacts during assembly of the contractile apparatus, as overexpression of CAP/Ponsin disrupted normal cell-matrix contact morphology.[8] In a mouse model of viral myocarditis due to Coxsackievirus infection, CAP/Ponsin stabilized antiviral type I interferon production and was protective against apoptosis and cytotoxicity.[9] CAP/Ponsin has also been shown to be a major regulator of insulin-stimulated signaling and regulation of glucose uptake, by potentiating insulin-induced phosphorylation and recruitment of CBL to a lipid raft signaling complex involving flotillin.[10] A role for CAP/Ponsin in macrophage function was illuminated by the finding that mice harboring SORBS1-deficient macrophages in bone marrow was protective against high-fat diet-induced insulin resistance and showed reduced inflammation.[7] In non-muscle cells, CAP/Ponsin inhibits cell spreading and focal adhesion turnover, as its siRNA-mediated knockdown resulted in enhanced PAK/MEK/ERK activation and cell migration.[11]
↑ 4.04.1Lin WH, Huang CJ, Liu MW, Chang HM, Chen YJ, Tai TY, Chuang LM (May 2001). "Cloning, mapping, and characterization of the human sorbin and SH3 domain containing 1 (SORBS1) gene: a protein associated with c-Abl during insulin signaling in the hepatoma cell line Hep3B". Genomics. 74 (1): 12–20. doi:10.1006/geno.2001.6541. PMID11374898.
↑Kioka N, Ueda K, Amachi T (Feb 2002). "Vinexin, CAP/ponsin, ArgBP2: a novel adaptor protein family regulating cytoskeletal organization and signal transduction". Cell Struct Funct. 27: 1–7. doi:10.1247/csf.27.1. PMID11937713.
↑ 7.07.1Lesniewski LA, Hosch SE, Neels JG, de Luca C, Pashmforoush M, Lumeng CN, Chiang SH, Scadeng M, Saltiel AR, Olefsky JM (Apr 2007). "Bone marrow-specific Cap gene deletion protects against high-fat diet-induced insulin resistance". Nature Medicine. 13 (4): 455–62. doi:10.1038/nm1550. PMID17351624.
↑ 8.08.18.2Gehmlich K, Pinotsis N, Hayess K, van der Ven PF, Milting H, El Banayosy A, Körfer R, Wilmanns M, Ehler E, Fürst DO (Jun 2007). "Paxillin and ponsin interact in nascent costameres of muscle cells". Journal of Molecular Biology. 369 (3): 665–82. doi:10.1016/j.jmb.2007.03.050. PMID17462669.
↑Valaperti A, Nishii M, Liu Y, Yang H, Naito K, Liu PP, Eriksson U (May 2014). "The adapter protein c-Cbl-associated protein (CAP) protects from acute CVB3-mediated myocarditis through stabilization of type I interferon production and reduced cytotoxicity". Basic Research in Cardiology. 109 (3): 411. doi:10.1007/s00395-014-0411-3. PMID24763933.
↑Baumann CA, Ribon V, Kanzaki M, Thurmond DC, Mora S, Shigematsu S, Bickel PE, Pessin JE, Saltiel AR (Sep 2000). "CAP defines a second signalling pathway required for insulin-stimulated glucose transport". Nature. 407 (6801): 202–7. doi:10.1038/35025089. PMID11001060.
↑Lin WH, Chiu KC, Chang HM, Lee KC, Tai TY, Chuang LM (Aug 2001). "Molecular scanning of the human sorbin and SH3-domain-containing-1 (SORBS1) gene: positive association of the T228A polymorphism with obesity and type 2 diabetes". Human Molecular Genetics. 10 (17): 1753–60. doi:10.1093/hmg/10.17.1753. PMID11532984.
↑ 13.013.1Haglund K, Ivankovic-Dikic I, Shimokawa N, Kruh GD, Dikic I (May 2004). "Recruitment of Pyk2 and Cbl to lipid rafts mediates signals important for actin reorganization in growing neurites". Journal of Cell Science. 117 (Pt 12): 2557–68. doi:10.1242/jcs.01148. PMID15128873.
↑ 14.014.1Vandenbroere I, Paternotte N, Dumont JE, Erneux C, Pirson I (Jan 2003). "The c-Cbl-associated protein and c-Cbl are two new partners of the SH2-containing inositol polyphosphate 5-phosphatase SHIP2". Biochemical and Biophysical Research Communications. 300 (2): 494–500. doi:10.1016/s0006-291x(02)02894-2. PMID12504111.
Kioka N (Nov 2002). "[A novel adaptor protein family regulating cytoskeletal organization and signal transduction--Vinexin, CAP/ponsin, ArgBP2]". Seikagaku. The Journal of Japanese Biochemical Society. 74 (11): 1356–60. PMID12510380.
Ribon V, Herrera R, Kay BK, Saltiel AR (Feb 1998). "A role for CAP, a novel, multifunctional Src homology 3 domain-containing protein in formation of actin stress fibers and focal adhesions". The Journal of Biological Chemistry. 273 (7): 4073–80. doi:10.1074/jbc.273.7.4073. PMID9461600.
Asakura T, Nakanishi H, Sakisaka T, Takahashi K, Mandai K, Nishimura M, Sasaki T, Takai Y (Oct 1999). "Similar and differential behaviour between the nectin-afadin-ponsin and cadherin-catenin systems during the formation and disruption of the polarized junctional alignment in epithelial cells". Genes to Cells. 4 (10): 573–81. doi:10.1046/j.1365-2443.1999.00283.x. PMID10583506.
Nagase T, Kikuno R, Ishikawa KI, Hirosawa M, Ohara O (Feb 2000). "Prediction of the coding sequences of unidentified human genes. XVI. The complete sequences of 150 new cDNA clones from brain which code for large proteins in vitro". DNA Research. 7 (1): 65–73. doi:10.1093/dnares/7.1.65. PMID10718198.
Lebre AS, Jamot L, Takahashi J, Spassky N, Leprince C, Ravisé N, Zander C, Fujigasaki H, Kussel-Andermann P, Duyckaerts C, Camonis JH, Brice A (May 2001). "Ataxin-7 interacts with a Cbl-associated protein that it recruits into neuronal intranuclear inclusions". Human Molecular Genetics. 10 (11): 1201–13. doi:10.1093/hmg/10.11.1201. PMID11371513.
Lin WH, Huang CJ, Liu MW, Chang HM, Chen YJ, Tai TY, Chuang LM (May 2001). "Cloning, mapping, and characterization of the human sorbin and SH3 domain containing 1 (SORBS1) gene: a protein associated with c-Abl during insulin signaling in the hepatoma cell line Hep3B". Genomics. 74 (1): 12–20. doi:10.1006/geno.2001.6541. PMID11374898.
Lin WH, Chiu KC, Chang HM, Lee KC, Tai TY, Chuang LM (Aug 2001). "Molecular scanning of the human sorbin and SH3-domain-containing-1 (SORBS1) gene: positive association of the T228A polymorphism with obesity and type 2 diabetes". Human Molecular Genetics. 10 (17): 1753–60. doi:10.1093/hmg/10.17.1753. PMID11532984.
Cowan CA, Henkemeyer M (Sep 2001). "The SH2/SH3 adaptor Grb4 transduces B-ephrin reverse signals". Nature. 413 (6852): 174–9. doi:10.1038/35093123. PMID11557983.
Vandenbroere I, Paternotte N, Dumont JE, Erneux C, Pirson I (Jan 2003). "The c-Cbl-associated protein and c-Cbl are two new partners of the SH2-containing inositol polyphosphate 5-phosphatase SHIP2". Biochemical and Biophysical Research Communications. 300 (2): 494–500. doi:10.1016/S0006-291X(02)02894-2. PMID12504111.
Yang WS, Lee WJ, Huang KC, Lee KC, Chao CL, Chen CL, Tai TY, Chuang LM (Apr 2003). "mRNA levels of the insulin-signaling molecule SORBS1 in the adipose depots of nondiabetic women". Obesity Research. 11 (4): 586–90. doi:10.1038/oby.2003.82. PMID12690089.