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ZFIN ID: ZDB-PUB-080408-3
Enzyme domain affects the movement of the voltage sensor in ascidian and zebrafish VSPs
Hossain, M.I., Iwasaki, H., Okochi, Y., Chahine, M., Higashijima, S., Nagayama, K., and Okamura, Y.
Date: 2008
Source: The Journal of biological chemistry   283(26): 18248-18259 (Journal)
Registered Authors: Higashijima, Shin-ichi
Keywords: none
MeSH Terms:
  • Amino Acid Sequence
  • Animals
  • Chick Embryo
  • Electrophysiology/methods
  • Enzyme Inhibitors/pharmacology
  • Gene Expression Regulation*
  • Humans
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Protein Structure, Tertiary
  • Rats
  • Urochordata
  • Xenopus
  • Zebrafish
PubMed: 18375390 Full text @ J. Biol. Chem.
ABSTRACT
The ascidian voltage-sensing phosphatase (Ci-VSP) consists of the voltage-sensor domain (VSD) and a cytoplasmic phosphatase region that has significant homology to the phosphatase and tensin homolog deleted on chromosome TEN (PTEN). The phosphatase activity of Ci-VSP is modified by the conformational change of the VSD. In many proteins, two protein modules are bidirectionally coupled, but it is unknown whether the phosphatase domain could affect the movement of the VSD in VSP. We addressed this issue by whole-cell patch recording of gating currents from a teleost VSP (Dr-VSP) cloned from Danio rerio expressed in tsA201 HEK cells. Replacement of a critical residue, cysteine, in the phosphatase active center of Dr-VSP by serine sharpened both ON- and OFF-gating currents. Similar changes were produced by treatment with phosphatase inhibitors, pervanadate and orthovanadate, s. Replacement of a critical residue, cysteine, in the phosphatase active center of Dr-VSP by serine sharpened both ON- and OFF-gating currents. that constitutively binds to cysteine in the active catalytic center of phosphatases. Distinct kinetics of gating currents dependent on enzyme activity was not due to altered PIP2 level, since kinetics of gating current was not changed under the condition of depletion of PIP2 as reported by coexpressed KCNQ2/3 channels. These indicate that the movement of the VSD is influenced by the enzyme state of the cytoplasmic domain, providing an important clue to understand mechanisms of coupling between VSD and its effector.
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