Shannon Katie B
Department of Biological Sciences, Missouri University of Science and Technology, Rolla, MO 65409, USA.
Int J Cell Biol. 2012;2012:894817. doi: 10.1155/2012/894817. Epub 2012 Feb 21.
IQGAPs are a family of scaffolding proteins with multiple domains, named for the IQ motifs and GTPase activating protein (GAP) related domains. Despite their GAP homology, IQGAP proteins act as effectors for GTP-bound GTPases of the Ras superfamily and do not stimulate GTP hydrolysis. IQGAPs are found in eukaryotic cells from yeast to human, and localize to actin-containing structures such as lamellipodia, membrane ruffles, cell-cell adhesions, phagocytic cups, and the actomyosin ring formed during cytokinesis. Mammalian IQGAPs also act as scaffolds for signaling pathways. IQGAPs perform their myriad functions through association with a large number of proteins including filamentous actin (F-actin), GTPases, calcium-binding proteins, microtubule binding proteins, kinases, and receptors. The focus of this paper is on recent studies describing new binding partners, mechanisms of regulation, and biochemical and physiological functions of IQGAPs in yeast, amoeba, and mammalian cells.
IQGAP蛋白是一类具有多个结构域的支架蛋白，因其IQ基序和GTP酶激活蛋白（GAP）相关结构域而得名。尽管它们与GAP具有同源性，但IQGAP蛋白作为Ras超家族中与GTP结合的GTP酶的效应器，并不刺激GTP水解。IQGAP蛋白存在于从酵母到人类的真核细胞中，并定位于含肌动蛋白的结构，如片状伪足、膜皱褶、细胞间粘附、吞噬杯以及胞质分裂期间形成的肌动球蛋白环。哺乳动物的IQGAP蛋白也作为信号通路的支架。IQGAP蛋白通过与大量蛋白质结合来执行其众多功能，这些蛋白质包括丝状肌动蛋白（F-肌动蛋白）、GTP酶、钙结合蛋白、微管结合蛋白、激酶和受体。本文的重点是最近的研究，这些研究描述了IQGAP蛋白在酵母、变形虫和哺乳动物细胞中的新结合伙伴、调节机制以及生化和生理功能。
