Coupling of the phosphatase activity of Ci-VSP to its voltage sensor activity over the entire range of voltage sensitivity

摘要

Non-technical summaryCi-VSP is a protein that consists of a voltage sensor domain (VSD) and a cytoplasmic phosphatase region. The phosphatase activity is regulated by the VSD. Detailed mechanisms of how the VSD regulates the phosphatase activity are elusive. The voltage range where the phosphatase activity is coupled with the VSD provides important clues to the coupling mechanisms. This paper examined the voltage sensitivity of the phosphatase activity over a wide range of voltage by electrophysiological methods, imaging analysis and mathematical modelling. The results demonstrate that the voltage dependency of the phosphatase activity correlates with that of the VSD. Thus, the phosphatase activity of Ci-VSP is coupled to the VSD over the entire range of voltages that elicit movement of the VSD.