Dynamic structural rearrangements and functional regulation of voltage‐sensing phosphatase
Dynamic structural rearrangements and functional regulation of voltage‐sensing phosphatase
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DOI：
10.1113/jp274113
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发表时间：
2018-11
期刊：
影响因子：
--
通讯作者：
Souhei Sakata;Y. Okamura
中科院分区：
文献类型：
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作者：
Souhei Sakata;Y. Okamura
电压敏感磷酸酶（VSP）由电压传感器结构域（VSD）和细胞质催化区组成。后者含有磷酸酶结构域和C2结构域，与肿瘤抑制酶PTEN显示出显著的相似性。在VSP中，膜去极化诱导VSD中的构象变化，其激活磷酸肌醇磷酸酶。VSP的最终结果是细胞质区域中的酶活性，这与电压门控离子通道不同，电压门控离子通道中跨膜孔的构象变化是由VSD诱导的。因此，检测胞质催化区的结构变化对深入了解VSP的运作机制至关重要。本文综述了最近的一项研究，其中一种非经典氨基酸，Anap的基因掺入方法，用于检测海鞘VSP（Ci-VSP）催化区结构的动态膜电压控制重排。在膜去极化时，磷酸酶结构域和C2结构域在类似的时间范围内移动，表明这两个区域彼此偶联。对引入Ci-VSP的C2结构域的Anap和细胞膜中的dipicrylamine之间的Förster共振能量转移（FRET）的测量表明，酶没有向膜的大的移动。由不同的膜电位诱导的Anap的荧光变化表明存在多种构象的活性酶。
The voltage‐sensing phosphatase (VSP) consists of a voltage sensor domain (VSD) and a cytoplasmic catalytic region. The latter contains a phosphatase domain and a C2 domain, showing remarkable similarity to the tumour suppressor enzyme PTEN. In VSP, membrane depolarization induces a conformational change in the VSD, which activates the phosphoinositide phosphatase. The final outcome in VSP is enzymatic activity in the cytoplasmic region, unlike in voltage‐gated ion channels where conformational change of the transmembrane pore is induced by the VSD. Therefore, it is crucial to detect structural change in the cytoplasmic catalytic region to gain insights into the operating mechanisms of VSP. This review summarizes a recent study in which a method of genetic incorporation of a non‐canonical amino acid, Anap, was used to detect dynamic membrane voltage‐controlled rearrangements of the structure of the catalytic region of sea squirt VSP (Ci‐VSP). Upon membrane depolarization, both the phosphatase domain and the C2 domain move in a similar time frame, suggesting that the two regions are coupled to each other. Measurement of Förster resonance energy transfer (FRET) between Anap introduced into the C2 domain of Ci‐VSP and dipicrylamine in the cell membrane suggested no large movement of the enzyme towards the membrane. Fluorescence changes in Anap induced by different membrane potentials indicate the presence of multiple conformations of the active enzyme.