Functions of cofilin, an actin-regulating protein

肌动蛋白丝切蛋白（一种肌动蛋白调节蛋白）的功能

基本信息

批准号：
09101002
负责人：
IIDA Kazuko
金额：
$ 131.84万
依托单位：
The Tokyo Metropolitan Institute of Medical Science
依托单位国家：
日本
项目类别：
Grant-in-Aid for Specially Promoted Research
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09101002/
关键词：
actin cofilin cell movement actrin filament severing acceleration of actin filament depolymerization growth cone collapse Aip1 cellular slime mold Cap1 収縮高浸透圧・ストレス神経突起 AIP1 高浸透圧ストレス GFP アクチン調節蛋白質 AIP 1

项目摘要

1) We improved the conventional method using fluorescently labeled actin, then demonstrated that cofilin severs actin filaments and accelerates monomer release at their pointed ends. Under substoichiometric conditions, 0.8 μM cofilin cut filamentous actin (2.2 μM) about every 270 monomer subunits and increased the depolymerization rate 5.7-fold at pH 7.1.2) Using cultured mammalian cell and Xnopus oocyte cell extracts, we identified two proteins, which bound to actin/cofilin comuln, to be Aipl and CAP.Yeast Aip1 was also found as a factor which suppresses the ts-phenotype of cof1 mutation. In Physarum polycepharum, a heat stress-induced cist-specific actin-binding protein was identified as Aip1. Aip1 suguments both actin filaments-severing and depolymerization-accelerating activities of cofilin.3) we identified a novel type of cofilin family member, cofilin-2, in D.discoideum. Cofilin- 2 consists of 143 amino acid residues. Cofilin-2 shows a significant homology (30.6% identity) to cof … More ilin-1 in its entire sequence, but does not retain some residues conserved among the cofilin family memners, suggesting that cofilin-2 belongs to a novel type of cofilin family. Purified cofilin-2 depolymerized actin filaments in a dose- and pH-dependent manner, but did not cosediment with actin filaments while cofilin-1 did. Cofilin-2 was not expressed in vegetative cells, and expresseion of coffin-2 is reduced during aggregation stage of development.4) we investigated the role of LIM-kinase 1, a protein that phosphorylates an actin depolymerizing protein, cofilin, in semaphorin 3A-induced growth cone collapse. We found that semaphorin 3A induces phosphorylation and dephosphorylation of cofilin at growth cones sequentially. A synthetic cell-permeable peptide containing a cofilin phosphorylation site inhibited LIM-kinase in vitro and in vivo, and essentially suppressed semaphorin 3A-induced growth cone collaplse. These data suggest that phosphorylation of cofilin by LIM-kinase is a critical signaling event in growht cone collapse by semaphorin 3A. Less

1）我们改进了使用荧光标记肌动蛋白的传统方法，然后证明肌丝蛋白丝切蛋白切断肌动蛋白丝并加速其尖端的单体释放，在亚化学计量条件下，0.8μM丝切蛋白切断约270个单体亚基的丝状肌动蛋白（2.2μM）并增加了单体的释放。 pH 7.1.2) 使用培养的哺乳动物细胞和 Xnopus 卵母细胞时，解聚率是 5.7 倍在细胞提取物中，我们鉴定了两种与肌动蛋白/cofilin comuln结合的蛋白质，即Aipl和CAP。在多头绒泡菌（一种热应激诱导的cist）中，酵母Aip1也被发现是抑制cof1突变的ts表型的因子。 -特异性肌动蛋白结合蛋白被鉴定为Aip1，Aip1增强肌动蛋白丝切断和解聚加速活性。 cofilin.3) 我们在 D.discoideum 中鉴定出一种新型的 cofilin 家族成员 cofilin-2，它由 143 个氨基酸残基组成，Cofilin-2 与 cof 具有显着的同源性（30.6% 同一性）。 ilin-1 的完整序列，但不保留 cofilin 家族成员中保守的一些残基，表明 cofilin-2 属于新型 cofilin纯化的 cofilin-2 以剂量和 pH 依赖性方式解聚肌动蛋白丝，但不与肌动蛋白丝共沉积，而 cofilin-1 在营养细胞中不表达，并且 coffin-2 的表达减少。在发育的聚集阶段。4) 我们研究了 LIM 激酶 1 的作用，LIM 激酶 1 是一种磷酸化肌动蛋白解聚的蛋白质信号蛋白 3A 诱导的生长锥塌陷中的蛋白丝切蛋白 (cofilin) 我们发现，丝蛋白蛋白 3A 在生长锥处依次诱导丝切蛋白磷酸化和去磷酸化，含有丝切蛋白磷酸化位点的合成细胞渗透肽在体外和体内抑制 LIM 激酶。并基本上抑制了 semaphorin 3A 诱导的生长锥塌陷。这些数据表明 semaphorin 的磷酸化。 LIM 激酶产生的 cofilin 是信号蛋白 3A 导致生长锥塌陷的关键信号事件。