The diaphanous-related formin DAAM1 collaborates with the Rho GTPases RhoA and Cdc42, CIP4 and Src in regulating cell morphogenesis and actin dynamics
The diaphanous-related formin DAAM1 collaborates with the Rho GTPases RhoA and Cdc42, CIP4 and Src in regulating cell morphogenesis and actin dynamics
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DOI：
10.1016/j.yexcr.2006.03.013
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发表时间：
2006-07-15
影响因子：
3.7
通讯作者：
Johansson, Ann-Sofi
中科院分区：
文献类型：
--
作者：
Aspenstrom, Pontus;Richnau, Ninna;Johansson, Ann-Sofi
通过酵母双杂交系统以及通过在免疫共沉淀实验中测试潜在的CIP4结合蛋白来鉴定Cdc42效应器CIP4的结合伴侣。对其中一种CIP 4结合蛋白DAAM 1进行了更详细的表征。DAAM1是哺乳动物透明相关formin的普遍表达成员，包括mDia1和mDia2等蛋白质。DAAM1在体内与CIP4的SH3结构域结合。异位表达的DAAM1定位在转染细胞的背侧的点状图案和蛋白质积累在附近的微管组织中心。此外，DAAM1的异位表达诱导细胞形态的显著改变，如细胞的圆整、分支突起的形成以及转染细胞中应力纤维的减少。免疫共沉淀实验表明DAAM 1以GTP依赖的方式与RhoA和Cdc42结合。此外，DAAM1被发现与非受体酪氨酸激酶Src相互作用和协作，形成分支突起。两者合计，我们的数据表明，DAAM1通信与Rho GTP酶，CIP4和Src的信号转导通路的调节，协调肌动蛋白丝系统的动态。(c)2006爱思唯尔公司All rights reserved.
Binding partners for the Cdc42 effector CIP4 were identified by the yeast two-hybrid system, as well as by testing potential CIP4-binding proteins in coimmunoprecipitation experiments. One of the CIP4-binding proteins, DAAM1, was characterised in more detail. DAAM1 is a ubiquitously expressed member of the mammalian diaphanous-related formins, which include proteins such as mDia1 and mDia2. DAAM1 was shown to bind to the SH3 domain of CIP4 in vivo. Ectopically expressed DAAM1 localised in dotted pattern at the dorsal side of transfected cells and the protein was accumulated in the proximity to the microtubule organising centre. Moreover, ectopic expression of DAAM1 induced a marked alteration of the cell morphology, seen as rounding up of the cells, the formation of branched protrusions as well as a reduction of stress-fibres in the transfected cells. Coimmunoprecipitation experiments demonstrated that DAAM1 bound to RhoA and Cdc42 in a GTP-dependent manner. Moreover, DAAM1 was found to interact and collaborate with the non-receptor tyrosine kinase Src in the formation of branched protrusions. Taken together, our data indicate that DAAM1 communicates with Rho GTPases, CIP4 and Src in the regulation of the signalling pathways that co-ordinate the dynamics of the actin filament system. (c) 2006 Elsevier Inc. All rights reserved.