Paduch M, Jeleń F, Otlewski J
Institute of Biochemistry and Molecular Biology, University of Wrocław, Poland.
Acta Biochim Pol. 2001;48(4):829-50.
In recent years small G proteins have become an intensively studied group of regulatory GTP hydrolases involved in cell signaling. More than 100 small G proteins have been identified in eucaryotes from protozoan to human. The small G protein superfamily includes Ras, Rho Rab, Rac, Sarl/Arf and Ran homologs, which take part in numerous and diverse cellular processes, such as gene expression, cytoskeleton reorganization, microtubule organization, and vesicular and nuclear transport. These proteins share a common structural core, described as the G domain, and significant sequence similarity. In this paper we review the available data on G domain structure, together with a detailed analysis of the mechanism of action. We also present small G protein regulators: GTPase activating proteins that bind to a catalytic G domain and increase its low intrinsic hydrolase activity, GTPase dissociation inhibitors that stabilize the GDP-bound, inactive state of G proteins, and guanine nucleotide exchange factors that accelerate nucleotide exchange in response to cellular signals. Additionally, in this paper we describe some aspects of small G protein interactions with down-stream effectors.
近年来，小G蛋白已成为细胞信号传导中一类深入研究的调节性GTP水解酶。从原生动物到人类的真核生物中已鉴定出100多种小G蛋白。小G蛋白超家族包括Ras、Rho、Rab、Rac、Sar1/Arf和Ran同源物，它们参与众多不同的细胞过程，如基因表达、细胞骨架重组、微管组织以及囊泡和核运输。这些蛋白质共享一个被称为G结构域的共同结构核心，并具有显著的序列相似性。在本文中，我们综述了有关G结构域结构的现有数据，并对作用机制进行了详细分析。我们还介绍了小G蛋白调节剂：与催化性G结构域结合并增加其低固有水解酶活性的GTP酶激活蛋白、稳定G蛋白结合GDP的无活性状态的GTP酶解离抑制剂，以及响应细胞信号加速核苷酸交换的鸟嘌呤核苷酸交换因子。此外，本文还描述了小G蛋白与下游效应器相互作用的一些方面。
