Regulation of the formin for3p by cdc42p and bud6p
Regulation of the formin for3p by cdc42p and bud6p
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DOI：
10.1091/mbc.e07-02-0094
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发表时间：
2007-10-01
影响因子：
3.3
通讯作者：
Chang, Fred
中科院分区：
文献类型：
--
作者：
Martin, Sophie G.;Rincon, Sergio A.;Chang, Fred
形成蛋白是保守的肌动蛋白成核剂，负责组装不同的肌动蛋白结构。许多formin通过涉及C-末端DAD序列与N-末端DID序列的相互作用的自抑制机制来控制。在这里，我们表明，裂变酵母cytofor 3 p，介导肌动蛋白电缆组装和极化细胞生长，是由一个类似的自抑制机制在体内调节。3 p定位于细胞尖端的多个位点起支配作用。for 3 p的定位和活性受到不同DAD和DID样序列的分子内相互作用的抑制。在内源性水平表达的for 3 p DAD突变体产生更稳健的肌动蛋白电缆，其似乎具有正常的组织和动力学。我们确定cdc 42 p作为主要的Rho GTdR参与肌动蛋白电缆组装和3 p调控。在for 3 p的N末端结合的cdc 42 p和在C末端DAD样序列附近结合的bud 6p都是for 3 p定位和完全活性所需的，但是for 3 p DAD中的突变恢复了cdc 42和bud 6突变体的for 3 p定位和其他表型。特别地，for 3 p DAD突变抑制bud 6 Delta细胞的双极生长（NETO）缺陷。这些发现表明cdc 42 p和bud 6p通过解除自身抑制激活for 3 p。
Formins are conserved actin nucleators responsible for the assembly of diverse actin structures. Many formins are controlled through an autoinhibitory mechanism involving the interaction of a C-terminal DAD sequence with an N-terminal DID sequence. Here, we show that the fission yeast formin for3p, which mediates actin cable assembly and polarized cell growth, is regulated by a similar autoinhibitory mechanism in vivo. Multiple sites govern for3p localization to cell tips. The localization and activity of for3p are inhibited by an intramolecular interaction of divergent DAD and DID-like sequences. A for3p DAD mutant expressed at endogenous levels produces more robust actin cables, which appear to have normal organization and dynamics. We identify cdc42p as the primary Rho GTPase involved in actin cable assembly and for3p regulation. Both cdc42p, which binds at the N terminus of for3p, and bud6p, which binds near the C-terminal DAD-like sequence, are needed for for3p localization and full activity, but a mutation in the for3p DAD restores for3p localization and other phenotypes of cdc42 and bud6 mutants. In particular, the for3p DAD mutation suppresses the bipolar growth (NETO) defect of bud6 Delta cells. These findings suggest that cdc42p and bud6p activate for3p by relieving autoinhibition.