Uncoupling PIP2-calmodulin regulation of Kv7.2 channels by an assembly destabilizing epileptogenic mutation
Uncoupling PIP2-calmodulin regulation of Kv7.2 channels by an assembly destabilizing epileptogenic mutation
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DOI：
10.1242/jcs.176420
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发表时间：
2015-11-01
影响因子：
4
通讯作者：
Villarroel, Alvaro
中科院分区：
文献类型：
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作者：
Alberdi, Araitz;Gomis-Perez, Carolina;Villarroel, Alvaro
我们展示了细胞内双部钙调蛋白（CaM）结合位点和远端组装区域的结合影响了离子通道如何被膜脂调节。我们的数据显示磷脂酰肌醇（4,5）二磷酸（PIP2）的调控和远离膜的细胞内线圈区域对组装的Kv7.2亚基的稳定是耦合的分子过程。活细胞荧光能量转移测量和直接结合研究表明，远程线圈-线圈形成为不同的CaM相互作用模式创造了条件，每种模式都赋予不同的PIP2对Kv7.2通道的依赖性。引起癫痫的突变破坏了卷曲线圈的形成，降低了CaM结合的明显亲和力，并中断了CaM对PIP2敏感性的影响。
We show that the combination of an intracellular bi-partite calmodulin (CaM)-binding site and a distant assembly region affect how an ion channel is regulated by a membrane lipid. Our data reveal that regulation by phosphatidylinositol(4,5)bisphosphate (PIP2) and stabilization of assembled Kv7.2 subunits by intracellular coiled-coil regions far from the membrane are coupled molecular processes. Live-cell fluorescence energy transfer measurements and direct binding studies indicate that remote coiled-coil formation creates conditions for different CaM interaction modes, each conferring different PIP2 dependency to Kv7.2 channels. Disruption of coiled-coil formation by epilepsy-causing mutation decreases apparent CaM-binding affinity and interrupts CaM influence on PIP2 sensitivity.