Characterization of a novel interaction between ELMO1 and ERM proteins
Characterization of a novel interaction between ELMO1 and ERM proteins
复制标题
DOI：
10.1074/jbc.m510647200
复制
发表时间：
2006-03-03
影响因子：
4.8
通讯作者：
Ravichandran, KS
中科院分区：
文献类型：
--
作者：
Grimsley, CM;Lu, MJ;Ravichandran, KS
ERMs是与细胞迁移、细胞粘附、细胞形状维持和微绒毛形成密切相关的蛋白质，其通过其将质膜与肌动蛋白细胞骨架交联的能力而参与。还已知埃尔莫蛋白通过ELMO-Dock 180复合物激活小GTP结合蛋白Rac来调节肌动蛋白细胞骨架重组。在这里，我们表明，ERM蛋白直接与ELMO 1作为纯化的重组蛋白在体外和在完整细胞的内源性水平。我们将ELMO 1上的ERM结合定位于N-末端280个氨基酸，其与结合GTdR RhoG所需的区域重叠，但与C-末端Dock 180结合区域不同。与此一致，ELMO 1可以同时结合radixin和Dock 180，尽管radixin没有通过Dock 180-埃尔莫复合物改变Rac激活。最有趣的是，根蛋白结合不影响埃尔莫与活性RhoG的结合，并且可以检测到活性RhoG-埃尔莫-根蛋白的三聚体复合物。此外，这三种蛋白共定位于质膜。最后，与大多数其他ERM结合蛋白相比，ELMO 1结合独立于根蛋白C末端磷酸化的状态发生，表明ELMO 1与活性和非活性形式的ERM蛋白相互作用，并暗示埃尔莫在某些细胞位点定位或保留ERM蛋白中可能起作用。总之，这些数据表明，ELMO 1介导的细胞骨架的变化可能是协调与ERM蛋白交联活性在动态细胞功能。
ERMs are closely related proteins involved in cell migration, cell adhesion, maintenance of cell shape, and formation of microvilli through their ability to cross-link the plasma membrane with the actin cytoskeleton. ELMO proteins are also known to regulate actin cytoskeleton reorganization through activation of the small GTP-binding protein Rac via the ELMO-Dock180 complex. Here we showed that ERM proteins associate directly with ELMO1 as purified recombinant proteins in vitro and at endogenous levels in intact cells. We mapped ERM binding on ELMO1 to the N-terminal 280 amino acids, which overlaps with the region required for binding to the GTPase RhoG, but is distinct from the C-terminal Dock180 binding region. Consistent with this, ELMO1 could simultaneously bind both radixin and Dock180, although radixin did not alter Rac activation via the Dock180-ELMO complex. Most interestingly, radixin binding did not affect ELMO binding to active RhoG and a trimeric complex of active RhoG-ELMO-radixin could be detected. Moreover, the three proteins colocalized at the plasma membrane. Finally, in contrast to most other ERM-binding proteins, ELMO1 binding occurred independently of the state of radixin C-terminal phosphorylation, suggesting an ELMO1 interaction with both the active and inactive forms of ERM proteins and implying a possible role of ELMO in localizing or retaining ERM proteins in certain cellular sites. Together these data suggest that ELMO1-mediated cytoskeletal changes may be coordinated with ERM protein cross-linking activity during dynamic cellular functions.