14-3-3 regulates actin dynamics by stabilizing phosphorylated cofilin
14-3-3 regulates actin dynamics by stabilizing phosphorylated cofilin
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DOI：
10.1016/s0960-9822(02)01184-3
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发表时间：
2002-10-01
期刊：
影响因子：
9.2
通讯作者：
Bokoch, GM
中科院分区：
文献类型：
--
作者：
Gohla, A;Bokoch, GM
肌动蛋白细胞骨架的功能取决于丝状肌动蛋白和单体肌动蛋白之间的动态平衡。 ADF/cofilin 家族的蛋白质对于通过调节肌动蛋白聚合/解聚循环在运动细胞中观察到的高肌动蛋白丝周转率至关重要 [1, 2]。 Rho GTPases 通过 p21 激活激酶 1 (Pak-1) [3] 和 Rho 激酶 [4] 发挥作用，通过 LIM 激酶 (LIMK) 介导的血清丝切蛋白磷酸化来抑制丝切蛋白活性 [5, 6]。我们报告了 14-3-3zeta 的鉴定，它是一种新型磷酸肌动蛋白结合蛋白，参与细胞磷酸肌动蛋白池的维持。从牛脑中纯化出血清磷酸肌动蛋白结合蛋白，并通过质谱鉴定为14-3-3zeta。下拉和免疫共沉淀实验证实了丝切蛋白和 14-3-3zeta 之间磷酸化依赖性相互作用。血清磷酸化和肌动蛋白丝切蛋白中的 14-3-3 识别基序都是 14-3-3 结合所必需的。 14-3-3 的表达会增加磷酸丝切蛋白水平，而 14-3-3zeta 与 LIMK 的共表达会进一步提高磷酸丝切蛋白水平并增强 LIMK 对肌动蛋白细胞骨架的依赖性作用。这种丝切蛋白作用的增强似乎是由于结合的 14-3-3zeta 保护磷酸丝切蛋白免受血清中磷酸酶介导的去磷酸化的结果。综上所述，这些结果表明 14-3-3zeta 蛋白可能通过维持磷酸肌动蛋白水平在细胞肌动蛋白结构的调节中发挥动态作用。
The functionality of the actin cytoskeleton depends on a dynamic equilibrium between filamentous and monomeric actin. Proteins of the ADF/cofilin family are essential for the high rates of actin filament turnover observed in motile cells through regulation of actin polymerization/depolymerization cycles [1, 2]. Rho GTPases act through p21-activated kinase-1 (Pak-1) [3] and Rho kinase [4] to inhibit cofilin activity via the LIM kinase (LIMK)-mediated phosphorylation of cofilin on Sera [5, 6]. We report the identification of 14-3-3zeta as a novel phosphocofilin binding protein involved in the maintenance of the cellular phosphocofilin pool. A Sera phosphocofilin binding protein was purified from bovine brain and was identified as 14-3-3zeta by mass spectrometry. The phosphorylation-dependent interaction between cofilin and 14-3-3zeta was confirmed in pulldown and coimmunoprecipitation experiments. Both Sera phosphorylation and a 14-3-3 recognition motif in cofilin are necessary for 14-3-3 binding. The expression of 14-3-3 increases phosphocofilin levels, and the coexpression of 14-3-3zeta with LIMK further elevates phosphocofilin levels and potentiates LIMK-dependent effects on the actin cytoskeleton. This potentiation of cofilin action appears to be a result of the protection of phosphocofilin from phosphatase-mediated dephosphorylation at Sera by bound 14-3-3zeta. Taken together, these results suggest that 14-3-3zeta proteins may play a dynamic role in the regulation of cellular actin structures through the maintenance of phosphocofilin levels.