Control of actin dynamics by proteins made of β-thymosin repeats -: The actobindin family
Control of actin dynamics by proteins made of β-thymosin repeats -: The actobindin family
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DOI：
10.1074/jbc.m112064200
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发表时间：
2002-04-26
影响因子：
4.8
通讯作者：
Carlier, MF
中科院分区：
文献类型：
--
作者：
Hertzog, M;Yarmola, EG;Carlier, MF
Actobindin是一种来自阿米巴的肌动蛋白结合蛋白，它由两个β-胸腺素重复序列组成，已被证明通过隔离G-肌动蛋白和稳定肌动蛋白二聚体来抑制肌动蛋白聚合。在这里，我们证明了actobindin具有与果蝇或秀丽线虫的同源蛋白相同的生化特性，该蛋白由三个β-胸腺素重复组成。这些蛋白质定义了一个新的肌动蛋白结合蛋白家族。它们以1：1的比例结合G-肌动蛋白，其热力学和动力学参数与β-胸腺素相似。和β-胸腺球蛋白一样，它们减缓G-肌动蛋白上的核苷酸交换，与G-肌动蛋白和Latrunculin A形成三元复合体。另一方面，它们与镁ATP-G-肌动蛋白的复合体与镁ATP-G-肌动蛋白复合体不同，参与细丝带刺末端的生长，就像Profilin-肌动蛋白复合体一样。因此，这些蛋白质在基于肌动蛋白的运动过程中起着积极的作用。此外，actobindin家族的蛋白与肌动蛋白细丝的尖端相互作用，并抑制尖端的生长，可能是通过β-胸腺素重复序列与两个末端亚基的相互作用。
Actobindin is an actin-binding protein from amoeba, which consists of two beta-thymosin repeats and has been shown to inhibit actin polymerization by sequestering G-actin and by stabilizing actin dimers. Here we show that actobindin has the same biochemical properties as the Drosophila or Caenorhabditis elegans homologous protein that consists of three beta-thymosin repeats. These proteins define a new family of actin-binding proteins. They bind G-actin in a 1:1 complex with thermodynamic and kinetic parameters similar to beta-thymosins. Like beta-thymosins, they slow down nucleotide exchange on G-actin and make a ternary complex with G-actin and Latrunculin A. On the other hand, they behave as functional homologs of profilin because their complex with MgATP-G-actin, unlike beta-thymosin-actin, participates in filament barbed end growth, like profilin-actin complex. Therefore these proteins play an active role in actin-based motility processes. In addition, proteins of the actobindin family interact with the pointed end of actin filaments and inhibit pointed end growth, maybe via the interaction of the beta-thymosin repeats with two terminal subunits.