ATP、ADP和二价阳离子在肌动蛋白、丝切蛋白和脱氧核糖核酸酶I二元及三元复合物形成中的作用。

The role of ATP, ADP and divalent cations in the formation of binary and ternary complexes of actin, cofilin and DNase I.

作者信息

Chhabra D, Nosworthy N J, dos Remedios C G

机构信息

Department of Anatomy and Histology, Institute for Biomedical Research, The University of Sydney, Australia.

出版信息

Electrophoresis. 2000 Nov;21(17):3863-9. doi: 10.1002/1522-2683(200011)21:17<3863::AID-ELPS3863>3.0.CO;2-C.

DOI:10.1002/1522-2683(200011)21:17<3863::AID-ELPS3863>3.0.CO;2-C

PMID:11271505

Abstract

Actin is the major cytoskeletal protein of virtually all eukaryotic cells. Actin assembly/disassembly is involved in a variety of cellular processes and actin-binding proteins are essential in regulation of the pool of actin monomers. Cofilin and DNase I are actin-binding proteins, which form both binary (actin-DNase 1, cofilin-actin) and ternary (cofilin-actin-DNase I) complexes with actin. Here we use native gel electrophoresis to examine the roles of ATP, ADP, Ca2+ and Mg2+ in the formation of these complexes as well as on the ability of actin to self-assemble. Conditions which favour actin polymerisation are: ATP (no Me2+) > or = ADP (no Me2+) > ADP-Ca2+ = ADP-Mg2+ > ATP-Mg2+ > ATP-Ca2+. Preferential conditions for the formation of the binary actin-cofilin complex are: ADP-Mg2+ > or = ADP-Ca2+ >> ATP-Ca2+ approximately equals ATP-Mg2+ approximately equals ADP-No Me2+ approximately equals ATP-No Me2+. Actin forms a very tight complex with DNase I in the order: ATP-Ca2+ > or = ATP-Mg2+ approximately equals ADP-Mg2+ approximately equals ADP-Ca2+ > or = ADP-(no Me2+) > ATP-(no Me2+). Effectively, the complex does not form in the presence of ATP and the absence of free Me2+. Finally, the conditions which favour the formation of a ternary complex of cofilin-actin-DNase I resemble the actin-DNase I, namely: ATP-Ca2+ approximately equals ADP-Ca2+ approximately equals ADP-Mg2+ approximately equals ATPMg2+ ADP (no Me2+) > ATP-(no Me2+).

摘要

肌动蛋白是几乎所有真核细胞中的主要细胞骨架蛋白。肌动蛋白的组装/解聚参与多种细胞过程，而肌动蛋白结合蛋白对于调节肌动蛋白单体库至关重要。丝切蛋白和脱氧核糖核酸酶I是肌动蛋白结合蛋白，它们与肌动蛋白形成二元复合物（肌动蛋白-脱氧核糖核酸酶I、丝切蛋白-肌动蛋白）和三元复合物（丝切蛋白-肌动蛋白-脱氧核糖核酸酶I）。在此，我们使用非变性凝胶电泳来研究ATP、ADP、Ca²⁺和Mg²⁺在这些复合物形成过程中的作用以及对肌动蛋白自我组装能力的影响。有利于肌动蛋白聚合的条件为：ATP（无Me²⁺）≥ADP（无Me²⁺）＞ADP-Ca²⁺ = ADP-Mg²⁺＞ATP-Mg²⁺＞ATP-Ca²⁺。二元肌动蛋白-丝切蛋白复合物形成的优先条件为：ADP-Mg²⁺≥ADP-Ca²⁺＞＞ATP-Ca²⁺≈ATP-Mg²⁺≈ADP-无Me²⁺≈ATP-无Me²⁺。肌动蛋白与脱氧核糖核酸酶I形成非常紧密的复合物，顺序为：ATP-Ca²⁺≥ATP-Mg²⁺≈ADP-Mg²⁺≈ADP-Ca²⁺≥ADP-（无Me²⁺）＞ATP-（无Me²⁺）。实际上，在ATP存在且无游离Me²⁺的情况下该复合物不形成。最后，有利于丝切蛋白-肌动蛋白-脱氧核糖核酸酶I三元复合物形成的条件类似于肌动蛋白-脱氧核糖核酸酶I的条件，即：ATP-Ca²⁺≈ADP-Ca²⁺≈ADP-Mg²⁺≈ATP-Mg²⁺ ADP（无Me²⁺）＞ATP-（无Me²⁺）。