Saito Y
Department of Pharmacology, Faculty of Medicine, Kyoto University, Japan.
Nihon Yakurigaku Zasshi. 1997 Jan;109(1):13-7. doi: 10.1254/fpj.109.13.
rho p21 is a member of the ras superfamily of small GTPases. Clostridium botulinum C3 exoenzyme ADP-ribosylates rho p21 at the Asp41 residue located at an effector domain and inhibits its biological activity by interfering with the interaction with its downstream effectors. The amount of rho p21 in cells or tissues is determined by the in vitro ADP-ribosylation reaction with C3 exoenzyme and 32P NAD. The studies using C3 exoenzyme have revealed that rho p21 is involved in the regulation of stress fiber formation, cell adhesion, contractile ring formation during cytokinesis and serum response factor-mediated activation of immediate early genes. C3 exoenzyme is a valuable tool for elucidating the unidentified function of rho p21 because the exoenzyme specifically inhibits rho p21-mediated signal transduction pathways. A Glu173 substitution mutant of the C3 exoenzyme lacking ADP-ribosyltransferase activity is useful for a control experiment.
rho p21是小GTP酶ras超家族的成员。肉毒杆菌C3外切酶在位于效应结构域的Asp41残基处对rho p21进行ADP核糖基化，并通过干扰其与下游效应物的相互作用来抑制其生物学活性。细胞或组织中rho p21的含量通过与C3外切酶和32P NAD的体外ADP核糖基化反应来确定。使用C3外切酶的研究表明，rho p21参与应激纤维形成、细胞黏附、胞质分裂期间收缩环形成以及血清反应因子介导的即刻早期基因激活的调节。C3外切酶是阐明rho p21未知功能的有价值工具，因为该外切酶特异性抑制rho p21介导的信号转导途径。缺乏ADP核糖基转移酶活性的C3外切酶的Glu173替代突变体可用于对照实验。
