Molecular dissection of the ILK-PINCH-parvin triad reveals a fundamental role for the ILK kinase domain in the late stages of focal-adhesion maturation
Molecular dissection of the ILK-PINCH-parvin triad reveals a fundamental role for the ILK kinase domain in the late stages of focal-adhesion maturation
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DOI：
10.1242/jcs.044602
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发表时间：
2009-06-01
影响因子：
4
通讯作者：
Van Obberghen-Schilling, Ellen
中科院分区：
文献类型：
--
作者：
Stanchi, Fabio;Grashoff, Carsten;Van Obberghen-Schilling, Ellen
整合素连接激酶（ILK）和PINCH和parvin家族的细胞质衔接子形成三元复合物，称为IPP，其定位于整合素粘附。我们在这里显示，ILK或PINCH 1编码基因的缺失同样通过下调张力蛋白的表达或募集以及使α 5 β 1-整合素-细胞骨架连接不稳定来阻断粘着斑向富含张力蛋白和磷酸酪氨酸贫乏的纤维状粘连（FB）的成熟。由于IPP组分对于整联蛋白靶向和蛋白质稳定性是相互依赖的，因此通过将ILK、PINCH、parvin或其单独的基序融合到β 3整联蛋白的胞质尾区（通常从FB中排除）来实现复合物的功能性分解。使用这种新的功能获得方法，我们证明了ILK的C-末端激酶结构域的表达可以恢复张力蛋白的募集，并促进IPP无效细胞的局部粘附成熟。ILK的桩蛋白或ATP结合位点的削弱性突变，以及α-parvin沉默，揭示了ILK-parvin关联的决定性作用，但不是直接桩蛋白结合，在此功能中。我们提出了一个模型，其中ILK的C-末端结构域通过加强α 5 β 1-整联蛋白-肌动蛋白连接促进整联蛋白分选，并通过靶向张力蛋白以使粘连成熟来控制力传递。
Integrin-linked kinase (ILK) and cytoplasmic adaptors of the PINCH and parvin families form a ternary complex, termed IPP, that localizes to integrin adhesions. We show here that deletion of the genes encoding ILK or PINCH1 similarly blocks maturation of focal adhesions to tensin-rich and phosphotyrosine-poor fibrillar adhesions (FBs) by downregulating expression or recruitment of tensin and destabilizing alpha 5 beta 1-integrin-cytoskeleton linkages. As IPP components are interdependent for integrin targeting and protein stability, functional dissection of the complex was achieved by fusing ILK, PINCH, parvin or their individual motifs to the cytoplasmic tail of beta 3 integrin, normally excluded from FBs. Using this novel gain-of-function approach, we demonstrated that expression of the C-terminal kinase domain of ILK can restore tensin recruitment and prompt focal-adhesion maturation in IPP-null cells. Debilitating mutations in the paxillin-or ATP-binding sites of ILK, together with alpha-parvin silencing, revealed a determinant role for ILK-parvin association, but not for direct paxillin binding, in this function. We propose a model in which the C-terminal domain of ILK promotes integrin sorting by reinforcing alpha 5 beta 1-integrin-actin linkage and controls force transmission by targeting tensin to maturing adhesions.