Fimbrin and tropomyosin competition regulates endocytosis and cytokinesis kinetics in fission yeast.
Fimbrin and tropomyosin competition regulates endocytosis and cytokinesis kinetics in fission yeast.
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DOI：
10.1016/j.cub.2010.06.020
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发表时间：
2010-08-24
期刊：
影响因子：
9.2
通讯作者：
Kovar, David R.
中科院分区：
文献类型：
--
作者：
Skau, Colleen T.;Kovar, David R.
原肌凝蛋白是一种重要的肌动蛋白丝稳定蛋白，控制其他必需蛋白进入肌动蛋白丝，包括肌凝蛋白马达、Arp2/3复合物、formin和cofilin。因此，建立调节肌动蛋白丝与原肌球蛋白结合的机制是至关重要的。我们研究了分裂酵母裂糖酵母（Schizosaccharomyces pombe）中肌动蛋白丝交联蛋白Fim1p和原肌球蛋白Cdc8p如何影响彼此结合丝的能力，定位到特定的细胞结构，并通过cofilin Adf1p调节丝的切断。我们发现了一种调节裂变酵母肌动蛋白丝动力学的新机制。在体外实验中，Fim1p抑制Cdc8p与肌动蛋白丝的结合，这允许adf1p介导的Cdc8p存在下的切断。在细胞中，Fim1p和Cdc8p之间的平衡对于细胞分裂期间的内吞肌动蛋白贴片动力学和收缩环组装都是重要的。高的Fim1p浓度阻止Cdc8p与肌动蛋白贴片结合，允许快速的贴片更新和运动。在缺乏Fim1p的情况下，Cdc8p异位定位于肌动蛋白斑块增加了斑块寿命，同时降低了斑块的运动性。在细胞分裂过程中，Fim1p和Cdc8p也发挥拮抗作用，其中Fim1p的缺失挽救了由Cdc8p突变引起的收缩环组装缺陷。纤凝蛋白Fim1p从肌动蛋白丝中分离原肌球蛋白Cdc8p，允许纤凝蛋白adf1p介导的切断。因此，我们提出除了肌动蛋白丝交联外，Fim1p作为一种积极的肌动蛋白结合“选择”蛋白具有新的作用，通过抑制Cdc8p促进其他蛋白进入肌动蛋白丝。
Tropomyosin is an important actin filament stabilizing protein that controls the access of other essential proteins to filaments including myosin motors, Arp2/3 complex, formin and cofilin. It is therefore critical to establish mechanisms for regulating actin filament binding of tropomyosin. We examined how the actin filament crosslinking protein fimbrin Fim1p and tropomyosin Cdc8p affect each other’s ability to bind filaments, localize to particular cellular structures and regulate filament severing by cofilin Adf1p in fission yeast Schizosaccharomyces pombe. We discovered a novel mechanism for regulating actin filament dynamics in fission yeast. Fim1p inhibits Cdc8p binding to actin filaments in vitro, which permits Adf1p-mediated severing in the presence of Cdc8p. In cells the balance between Fim1p and Cdc8p is important for both endocytic actin patch kinetics and contractile ring assembly during cytokinesis. High Fim1p concentrations prevent Cdc8p from associating with actin patches, allowing rapid patch turnover and motility. In the absence of Fim1p, ectopic localization of Cdc8p to actin patches increases patch lifetime while decreasing patch motility. Fim1p and Cdc8p also play antagonistic roles during cytokinesis, where deletion of Fim1p rescues the contractile ring assembly defects caused by mutation of Cdc8p. Fimbrin Fim1p dissociates tropomyosin Cdc8p from actin filaments, permitting cofilin Adf1p-mediated severing. Therefore, we propose that in addition to actin filament crosslinking, Fim1p has a novel role as a positive actin-binding ‘selector’ protein that promotes the access of other proteins to actin filaments by inhibiting Cdc8p.
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DOI：
10.1083/jcb.200502053
发表时间：
2005-08-15
期刊：
The Journal of cell biology
影响因子：
--
作者：
Sirotkin V;Beltzner CC;Marchand JB;Pollard TD
通讯作者：
Pollard TD
影响因子：
3.3
作者：
Kovar, DR;Wu, JQ;Pollard, TD
通讯作者：
Pollard, TD
影响因子：
3.3
作者：
Coffman, Valerie C.;Nile, Aaron H.;Wu, Jian-Qiu
通讯作者：
Wu, Jian-Qiu
影响因子：
64.5
作者：
Kaksonen, M;Toret, CP;Drubin, DG
通讯作者：
Drubin, DG
影响因子：
3.3
作者：
Skau, Colleen T.;Neidt, Erin M.;Kovar, David R.
通讯作者：
Kovar, David R.