CASPR explained

CASPR should not be confused with CRISPR.

CASPR also known as Contactin associated protein 1, Paranodin and CASPR1 is a protein that in humans is encoded by the CNTNAP1 gene.^[1] CASPR is a part of the neurexin family of proteins, hence its another name "Neurexin IV".^[2] CASPR is a membrane protein found in the neuronal membrane in the paranodal section of the axon in myelinated neurons, between the Nodes of Ranvier containing Na+ channels, and juxtaparanode, which contains K+ channels.^[3] During myelination, caspr associates with contactin in a cis complex,^[3] though its precise role in myelination is not yet understood.

Function

The gene product was initially identified as a 190-kD protein associated with the contactin-PTPRZ1 complex. The 1,384-amino acid protein, also designated p190 or CASPR for 'contactin-associated protein,' includes an extracellular domain with several putative protein-protein interaction domains, a putative transmembrane domain, and a 74-amino acid cytoplasmic domain. Northern blot analysis showed that the gene is transcribed predominantly in brain as a transcript of 6.2 kb, with weak expression in several other tissues tested. The architecture of its extracellular domain is similar to that of neurexins, and this protein may be the signaling subunit of contactin, enabling recruitment and activation of intracellular signaling pathways in neurons. [provided by RefSeq, Jan 2009].

Clinical

Mutations in CNTNAP1 cause arthrogryposis multiplex congenita.^[4]

Other diseases associated with mutations in this gene include lethal congenital contracture syndrome type 7 and congenital hypomyelinating neuropathy type 3.^[5]

Further reading

• Martins-de-Souza D, Guest PC, Mann DM, Roeber S, Rahmoune H, Bauder C, Kretzschmar H, Volk B, Baborie A, Bahn S . Proteomic analysis identifies dysfunction in cellular transport, energy, and protein metabolism in different brain regions of atypical frontotemporal lobar degeneration . Journal of Proteome Research . 11 . 4 . 2533–43 . April 2012 . 22360420 . 10.1021/pr2012279 .
• Velez Edwards DR, Naj AC, Monda K, North KE, Neuhouser M, Magvanjav O, Kusimo I, Vitolins MZ, Manson JE, O'Sullivan MJ, Rampersaud E, Edwards TL . Gene-environment interactions and obesity traits among postmenopausal African-American and Hispanic women in the Women's Health Initiative SHARe Study . Human Genetics . 132 . 3 . 323–36 . March 2013 . 23192594 . 3704217 . 10.1007/s00439-012-1246-3 .
• Li R, Zhang B, Zheng Y . Structural determinants required for the interaction between Rho GTPase and the GTPase-activating domain of p190 . The Journal of Biological Chemistry . 272 . 52 . 32830–5 . December 1997 . 9407060 . 10.1074/jbc.272.52.32830 . free .
• Lee JY, Park AK, Lee KM, Park SK, Han S, Han W, Noh DY, Yoo KY, Kim H, Chanock SJ, Rothman N, Kang D . Candidate gene approach evaluates association between innate immunity genes and breast cancer risk in Korean women . Carcinogenesis . 30 . 9 . 1528–31 . September 2009 . 19372141 . 10.1093/carcin/bgp084 . free .
• Peles E, Nativ M, Lustig M, Grumet M, Schilling J, Martinez R, Plowman GD, Schlessinger J . Identification of a novel contactin-associated transmembrane receptor with multiple domains implicated in protein-protein interactions . The EMBO Journal . 16 . 5 . 978–88 . March 1997 . 9118959 . 1169698 . 10.1093/emboj/16.5.978 .
• Hur JY, Teranishi Y, Kihara T, Yamamoto NG, Inoue M, Hosia W, Hashimoto M, Winblad B, Frykman S, Tjernberg LO . Identification of novel γ-secretase-associated proteins in detergent-resistant membranes from brain . The Journal of Biological Chemistry . 287 . 15 . 11991–2005 . April 2012 . 22315232 . 3320946 . 10.1074/jbc.M111.246074 . free .
• Venken K, Meuleman J, Irobi J, Ceuterick C, Martini R, De Jonghe P, Timmerman V . Caspr1/Paranodin/Neurexin IV is most likely not a common disease-causing gene for inherited peripheral neuropathies . NeuroReport . 12 . 11 . 2609–14 . August 2001 . 11496158 . 10.1097/00001756-200108080-00063 . 28331998 .
• Charles P, Tait S, Faivre-Sarrailh C, Barbin G, Gunn-Moore F, Denisenko-Nehrbass N, Guennoc AM, Girault JA, Brophy PJ, Lubetzki C . Neurofascin is a glial receptor for the paranodin/Caspr-contactin axonal complex at the axoglial junction . Current Biology . 12 . 3 . 217–20 . February 2002 . 11839274 . 10.1016/S0960-9822(01)00680-7 . 18017227 . free . 2002CBio...12..217C .
• Nie DY, Zhou ZH, Ang BT, Teng FY, Xu G, Xiang T, Wang CY, Zeng L, Takeda Y, Xu TL, Ng YK, Faivre-Sarrailh C, Popko B, Ling EA, Schachner M, Watanabe K, Pallen CJ, Tang BL, Xiao ZC . Nogo-A at CNS paranodes is a ligand of Caspr: possible regulation of K(+) channel localization . The EMBO Journal . 22 . 21 . 5666–78 . November 2003 . 14592966 . 275427 . 10.1093/emboj/cdg570 .

Notes and References

1. Web site: Entrez Gene: Contactin associated protein 1 .
2. Web site: OMIM Entry- * 602346 - CONTACTIN-ASSOCIATED PROTEIN 1; CNTNAP1. omim.org. en-us. 2017-04-27.
3. Contactin-Associated Protein (Caspr) and Contactin Form a Complex That Is Targeted to the Paranodal Junctions during Myelination. Jose C.. Rios. Carmen V.. Melendez-Vasquez. Steven. Einheber. Marc. Lustig. Martin. Grumet. John. Hemperly. Elior. Peles. James L.. Salzer. 15 November 2000. J. Neurosci.. 20. 22. 8354–8364. 11069942. 10.1523/JNEUROSCI.20-22-08354.2000. 6773165. free.
4. Laquérriere A, Maluenda J, Camus A, Fontenas L, Dieterich K, Nolent F, Zhou J, Monnier N, Latour P, Gentil D, Héron D, Desguerres I, Landrieu P, Beneteau C, Delaporte B, Bellesme C, Baumann C, Capri Y, Goldenberg A, Lyonnet S, Bonneau D, Estournet B, Quijano-Roy S, Francannet C, Odent S, Saint-Frison MH, Sigaudy S, Figarella-Branger D, Gelot A, Mussini JM, Lacroix C, Drouin-Garraud V, Malinge MC, Attié-Bitach T, Bessieres B, Bonniere M, Encha-Razavi F, Beaufrère AM, Khung-Savatovsky S, Perez MJ, Vasiljevic A, Mercier S, Roume J, Trestard L, Saugier-Veber P, Cordier MP, Layet V, Legendre M, Vigouroux-Castera A, Lunardi J, Bayes M, Jouk PS, Rigonnot L, Granier M, Sternberg D, Warszawski J, Gut I, Gonzales M, Tawk M, Melki J . Mutations in CNTNAP1 and ADCY6 are responsible for severe arthrogryposis multiplex congenita with axoglial defects . Human Molecular Genetics . 23 . 9 . 2279–89 . May 2014 . 24319099 . 10.1093/hmg/ddt618 . free .
5. Sabbagh S, Antoun S, Mégarbané A (2020) CNTNAP1 Mutations and Their Clinical Presentations: New Case Report and Systematic Review. Case Rep Med 2020:8795607.