Horn Richard
Department of Physiology, Institute of Hyperexcitability, Jefferson Medical College, 1020 Locust Street, Philadelphia, PA 19107, USA.
Sci STKE. 2005 Oct 25;2005(307):pe50. doi: 10.1126/stke.3072005pe50.
Ci-VSP, a recently described protein with sequence similarity to both the voltage-sensing domain of a voltage-gated potassium channel and the phosphatase PTEN, functions as a transmembrane phosphoinositide phosphatase that is regulated by changes in voltage across the plasma membrane. Ci-VSP dephosphorylated phosphatidylinositol-3,4,5-trisphosphate [PtdIns(3,4,5)P3] in vitro, exhibited capacitative currents that resembled ion channel gating currents, and, when coexpressed with potassium channels that are regulated by PtdIns(4,5)P2, conferred sensitivity of potassium current amplitude to prolonged changes in membrane potential. How the voltage-sensing (VS) domain of Ci-VSP communicates with the phosphatase domain, and how the VS domain moves its charges across the membrane electric field in the absence of a transmembrane pore domain, remain to be determined.
Ci-VSP是一种最近被描述的蛋白质，其序列与电压门控钾通道的电压感应结构域和磷酸酶PTEN均有相似性，它作为一种跨膜磷酸肌醇磷酸酶发挥作用，受质膜两侧电压变化的调节。Ci-VSP在体外可使磷脂酰肌醇-3,4,5-三磷酸[PtdIns(3,4,5)P3]去磷酸化，表现出类似于离子通道门控电流的电容性电流，并且当与受PtdIns(4,5)P2调节的钾通道共表达时，会使钾电流幅度对膜电位的长期变化产生敏感性。Ci-VSP的电压感应（VS）结构域如何与磷酸酶结构域进行通讯，以及在没有跨膜孔结构域的情况下VS结构域如何在膜电场中移动其电荷，仍有待确定。
