| Structural highlights
Disease
[CSKP_HUMAN] Defects in CASK are the cause of mental retardation and microcephaly with pontine and cerebellar hypoplasia (MICPCH) [MIM:300749]. A disorder characterized by significantly below average general intellectual functioning associated with impairments in adaptative behavior and manifested during the developmental period. Patients with mental retardation X-linked CASK-related can manifest a severe phenotype consisting of severe intellectual deficit, congenital or postnatal microcephaly, disproportionate brainstem and cerebellar hypoplasia. A milder phenotype consists of mental retardation alone or associated with nystagmus.[1] Defects in CASK are the cause of FG syndrome type 4 (FGS4) [MIM:300422]. FG syndrome (FGS) is an X-linked disorder characterized by mental retardation, relative macrocephaly, hypotonia and constipation.[2]
Function
[CSKP_HUMAN] Multidomain scaffolding protein with a role in synaptic transmembrane protein anchoring and ion channel trafficking. Contributes to neural development and regulation of gene expression via interaction with the transcription factor TRB1. Binds to cell-surface proteins, including amyloid precursor protein, neurexins and syndecans. May mediate a link between the extracellular matrix and the actin cytoskeleton via its interaction with syndecan and with the actin/spectrin-binding protein 4.1.
Publication Abstract from PubMed
Liprins are highly conserved scaffold proteins that regulate cell adhesion, cell migration, and synapse development by binding to diverse target proteins. The molecular basis governing liprin/target interactions is poorly understood. The liprin-alpha2/CASK complex structure solved here reveals that the three SAM domains of liprin-alpha form an integrated supramodule that binds to the CASK kinase-like domain. As supported by biochemical and cellular studies, the interaction between liprin-alpha and CASK is unique to vertebrates, implying that the liprin-alpha/CASK interaction is likely to regulate higher-order brain functions in mammals. Consistently, we demonstrate that three recently identified X-linked mental retardation mutants of CASK are defective in binding to liprin-alpha. We also solved the liprin-alpha/liprin-beta SAM domain complex structure, which uncovers the mechanism underlying liprin heterodimerizaion. Finally, formation of the CASK/liprin-alpha/liprin-beta ternary complex suggests that liprins can mediate assembly of target proteins into large protein complexes capable of regulating numerous cellular activities.
Liprin-mediated large signaling complex organization revealed by the liprin-alpha/CASK and liprin-alpha/liprin-beta complex structures.,Wei Z, Zheng S, Spangler SA, Yu C, Hoogenraad CC, Zhang M Mol Cell. 2011 Aug 19;43(4):586-98. PMID:21855798[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Najm J, Horn D, Wimplinger I, Golden JA, Chizhikov VV, Sudi J, Christian SL, Ullmann R, Kuechler A, Haas CA, Flubacher A, Charnas LR, Uyanik G, Frank U, Klopocki E, Dobyns WB, Kutsche K. Mutations of CASK cause an X-linked brain malformation phenotype with microcephaly and hypoplasia of the brainstem and cerebellum. Nat Genet. 2008 Sep;40(9):1065-7. doi: 10.1038/ng.194. PMID:19165920 doi:10.1038/ng.194
- ↑ Piluso G, D'Amico F, Saccone V, Bismuto E, Rotundo IL, Di Domenico M, Aurino S, Schwartz CE, Neri G, Nigro V. A missense mutation in CASK causes FG syndrome in an Italian family. Am J Hum Genet. 2009 Feb;84(2):162-77. doi: 10.1016/j.ajhg.2008.12.018. Epub 2009, Feb 5. PMID:19200522 doi:10.1016/j.ajhg.2008.12.018
- ↑ Wei Z, Zheng S, Spangler SA, Yu C, Hoogenraad CC, Zhang M. Liprin-mediated large signaling complex organization revealed by the liprin-alpha/CASK and liprin-alpha/liprin-beta complex structures. Mol Cell. 2011 Aug 19;43(4):586-98. PMID:21855798 doi:10.1016/j.molcel.2011.07.021
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