Ca2+-dependent binding and activation of dormant ezrin by dimeric, S100P
Ca2+-dependent binding and activation of dormant ezrin by dimeric, S100P
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DOI：
10.1091/mbc.e02-09-0553
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发表时间：
2003-06-01
影响因子：
3.3
通讯作者：
Gerke, V
中科院分区：
文献类型：
--
作者：
Koltzscher, M;Neumann, C;Gerke, V
S100蛋白是EF手型Ca2+结合蛋白，被认为通过结合并以Ca2+依赖的方式调节细胞靶标，在刺激-反应偶联中起作用。为了分离S100P蛋白的这些靶标，我们设计了一种亲和层析方法，选择需要生物活性S100二聚体进行相互作用的S100蛋白配体。因此，我们确定ezrin，一种膜/ f -肌动蛋白交联蛋白，作为二聚体特异性S100P配体。S100P-ezrin复合体的形成依赖于Ca2+，并且很可能发生在细胞内，因为两种蛋白质在生长因子或Ca2+离子载体刺激后在质膜上共定位。S100P结合位点位于ezrin的N端结构域，在休眠的ezrin中可以相互作用，其中f -肌动蛋白和跨膜蛋白的结合位点通过N端和c端结构域之间的关联被掩盖。有趣的是，S100P结合揭示了F-actin结合位点，从而至少部分激活了ezrin分子。这表明S100P是一种新的ezrin激活剂，并表明ezrin交联功能的激活可以直接发生在Ca2+瞬态反应中。
S100 proteins are EF hand type Ca2+ binding proteins thought to function in stimulus-response coupling by binding to and thereby regulating cellular targets in a Ca2+-dependent manner. To isolate such target(s), of the S100P protein we devised an affinity chromatography approach that selects for S100 protein ligands requiring the biologically active S100 dimer for interaction. Hereby we identify ezrin, a membrane/F-actin cross-linking protein, as a dimer-specific S100P ligand. S100P-ezrin complex formation is Ca2+ dependent and most likely occurs within cells because both proteins colocalize at the plasma membrane after growth factor or Ca2+ ionophore stimulation. The S100P binding site is, located in the N-terminal domain of ezrin and is accessible for interaction in dormant ezrin, in which binding sites for F-actin and transmembrane proteins are masked through an association between the N- and C-terminal domains. Interestingly, S100P binding unmasks the F-actin binding site, thereby at least partially activating the ezrin molecule. This identifies S100P as a novel activator of ezrin and indicates that activation of ezrin's crosslinking function can occur directly in response to Ca2+ transients.