Coupling between the voltage-sensing and phosphatase domains of Ci-VSP.
Coupling between the voltage-sensing and phosphatase domains of Ci-VSP.
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DOI：
10.1085/jgp.200910215
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发表时间：
2009-07
期刊：
影响因子：
--
通讯作者：
Bezanilla F
中科院分区：
文献类型：
--
作者：
Villalba-Galea CA;Miceli F;Taglialatela M;Bezanilla F
含有磷酸酶的海鞘电压传感器 (Ci-VSP) 与称为 PTEN（10 号染色体上删除的磷酸酶和张力蛋白同源物）的磷脂酰肌醇磷酸酶具有高度同源性。我们利用这些蛋白质之间的相似性来探究 Ci-VSP 中电压传感和磷酸酶结构域之间的耦合。最近，研究表明 PTEN 中的四个碱性残基（R11、K13、R14 和 R15）对于其与膜的结合至关重要，这是其催化活性所必需的。 Ci-VSP 具有 PTEN 的三个基本残基。在这里，我们表明，当 R253 和 R254（PTEN 中 R14 和 R15 的同源物）在 Ci-VSP 中突变为丙氨酸时，磷酸酶活性被破坏，这通过对 KCNQ2/3 离子电流缺乏影响来揭示，其中电流降低是磷酸酶活性的量度。引入赖氨酸并未恢复酶活性，这表明该结合是磷酸酶结合结构域和膜之间的精氨酸特异性相互作用，可能是通过磷脂的磷酸基团进行的。我们还发现，当精氨酸不存在时，S4 段运动的动力学和稳态电压依赖性受到影响，这表明磷酸酶催化作用所需的 R253 和 R254 与膜的相互作用限制了电压传感器的运动。
The Ciona intestinalis voltage sensor–containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues of R14 and R15 in PTEN) are mutated to alanines in Ci-VSP, phosphatase activity is disrupted, as revealed by a lack of effect on the ionic currents of KCNQ2/3, where current decrease is a measure of phosphatase activity. The enzymatic activity was not rescued by the introduction of lysines, indicating that the binding is an arginine-specific interaction between the phosphatase binding domain and the membrane, presumably through the phosphate groups of the phospholipids. We also found that the kinetics and steady-state voltage dependence of the S4 segment movement are affected when the arginines are not present, indicating that the interaction of R253 and R254 with the membrane, required for the catalytic action of the phosphatase, restricts the movement of the voltage sensor.
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DOI：
10.1085/jgp.112.4.391
发表时间：
1998-10
期刊：
The Journal of general physiology
影响因子：
--
作者：
Cha A;Bezanilla F
通讯作者：
Bezanilla F
影响因子：
5.5
作者：
Murata, Yoshimichi;Okamura, Yasushi
通讯作者：
Okamura, Yasushi
DOI：
10.1073/pnas.0807387105
发表时间：
2008-11-18
影响因子：
11.1
作者：
Villalba-Galea, Carlos A.;Sandtner, Walter;Bezanilla, Francisco
通讯作者：
Bezanilla, Francisco
影响因子：
4.8
作者：
Halaszovich, Christian R.;Schreiber, Daniela N.;Oliver, Dominik
通讯作者：
Oliver, Dominik
影响因子：
64.8
作者：
Murata, Y;Iwasaki, H;Okamura, Y
通讯作者：
Okamura, Y