Structural basis of Focal Adhesion Kinase activation on lipid membranes
Structural basis of Focal Adhesion Kinase activation on lipid membranes
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DOI：
10.15252/embj.2020104743
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发表时间：
2020-08-11
期刊：
影响因子：
11.4
通讯作者：
Lietha, Daniel
中科院分区：
文献类型：
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作者：
Acebron, Ivan;Righetto, Ricardo D.;Lietha, Daniel
粘着斑激酶（FAK）是粘着斑复合物中膜近端信号层的关键组分，调节重要的细胞过程，包括细胞迁移、增殖和存活。在胞质溶胶中，FAK呈自抑制状态，但在募集到局灶性粘连时被激活，但这是如何发生的或什么诱导了结构变化尚不清楚。在这里，我们采用冷冻电子显微镜来揭示FAK如何与脂质膜结合，以及膜相互作用如何解除FAK自身抑制以促进激活。有趣的是，FAK与膜的初始结合导致空间冲突，使激酶结构域从自抑制中释放出来，使其经历大的构象变化，并以将活性位点朝向膜的方向与膜相互作用。在这种构象中，自磷酸化位点暴露，多个界面对齐以促进膜上的FAK寡聚化。我们发现，负责初始二聚化和膜附着的界面对于FAK自磷酸化和由此产生的细胞活性（包括癌细胞侵袭）是必不可少的，而稳定的FAK寡聚化似乎是以锚定非依赖性方式进行最佳癌细胞增殖所必需的。总之，我们的数据提供了一个关键的膜结合状态ofFAK的结构细节，这是有效的自磷酸化和激活，从而揭示了整合素介导的FAK激活和信号在局灶性粘连的关键事件。
Focal adhesion kinase (FAK) is a key component of the membrane proximal signaling layer in focal adhesion complexes, regulating important cellular processes, including cell migration, proliferation, and survival. In the cytosol,FAKadopts an autoinhibited state but is activated upon recruitment into focal adhesions, yet how this occurs or what induces structural changes is unknown. Here, we employ cryo-electron microscopy to reveal howFAKassociates with lipid membranes and how membrane interactions unlockFAKautoinhibition to promote activation. Intriguingly, initial binding ofFAKto the membrane causes steric clashes that release the kinase domain from autoinhibition, allowing it to undergo a large conformational change and interact itself with the membrane in an orientation that places the active site toward the membrane. In this conformation, the autophosphorylation site is exposed and multiple interfaces align to promoteFAKoligomerization on the membrane. We show that interfaces responsible for initial dimerization and membrane attachment are essential forFAKautophosphorylation and resulting cellular activity including cancer cell invasion, while stableFAKoligomerization appears to be needed for optimal cancer cell proliferation in an anchorage-independent manner. Together, our data provide structural details of a key membrane bound state ofFAKthat is primed for efficient autophosphorylation and activation, hence revealing the critical event in integrin mediatedFAKactivation and signaling at focal adhesions.