Allosteric regulation of focal adhesion kinase by PIP₂ and ATP.
Allosteric regulation of focal adhesion kinase by PIP₂ and ATP.
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DOI：
10.1016/j.bpj.2014.11.3454
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发表时间：
2015-02
影响因子：
3.4
通讯作者：
Jing Zhou;A. Bronowska;J. Le Coq;D. Lietha;F. Gräter
中科院分区：
文献类型：
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作者：
Jing Zhou;A. Bronowska;J. Le Coq;D. Lietha;F. Gräter
局灶黏附激酶（FAK）是一种非受体酪氨酸激酶，调节细胞信号传导、增殖、迁移和发育。调控FAK活性的主要机制是其两个结构域（催化结构域和FERM结构域）之间的分子内自抑制相互作用。当细胞粘附到细胞外基质时，FAK被转移到黏附部位并被激活。FAK与磷酸肌肽磷脂酰肌醇-4,5-二磷酸（PIP2）相互作用是激活FAK的必要条件。然而，激活的分子机制仍然知之甚少。最近的荧光共振能量转移实验显示，ATP结合后，ferm -激酶界面关闭，而PIP2的额外结合则逆转。在这里，我们通过对含有催化结构域和FERM结构域的FAK片段进行全原子分子动力学模拟来研究FAK的变构调节，并比较了ATP和PIP2缺失或存在时的动力学。作为一个主要的构象变化，我们观察到ATP和额外的pip2结合分别发生了闭合和打开运动，这与荧光共振能量转移实验很好地吻合。为了揭示调控pip2与FERM F2叶的结合是如何被转导到非常遥远的F1/ n叶界面的，我们采用了力分布分析。我们确定了一个主要带电残基-残基相互作用的网络，从pip2结合位点跨越到激酶和FERM结构域之间的远端界面，包括突变的候选残基，以验证FAK激活的预测机制。
Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that regulates cell signaling, proliferation, migration, and development. A major mechanism of regulation of FAK activity is an intramolecular autoinhibitory interaction between two of its domains—the catalytic and FERM domains. Upon cell adhesion to the extracellular matrix, FAK is being translocated toward focal adhesion sites and activated. Interactions of FAK with phosphoinositide phosphatidylinsositol-4,5-bis-phosphate (PIP2) are required to activate FAK. However, the molecular mechanism of the activation remains poorly understood. Recent fluorescence resonance energy transfer experiments revealed a closure of the FERM-kinase interface upon ATP binding, which is reversed upon additional binding of PIP2. Here, we addressed the allosteric regulation of FAK by performing all-atom molecular-dynamics simulations of a FAK fragment containing the catalytic and FERM domains, and comparing the dynamics in the absence or presence of ATP and PIP2. As a major conformational change, we observe a closing and opening motion upon ATP and additional PIP2binding, respectively, in good agreement with the fluorescence resonance energy transfer experiments. To reveal how the binding of the regulatory PIP2to the FERM F2 lobe is transduced to the very distant F1/N-lobe interface, we employed force distribution analysis. We identified a network of mainly charged residue-residue interactions spanning from the PIP2binding site to the distant interface between the kinase and FERM domains, comprising candidate residues for mutagenesis to validate the predicted mechanism of FAK activation.