Interaction between S4 and the phosphatase domain mediates electrochemical coupling in voltage-sensing phosphatase (VSP)

Proc Natl Acad Sci U S A. 2022 Jun 28;119(26):e2200364119. doi: 10.1073/pnas.2200364119. Epub 2022 Jun 21.

Abstract

Voltage-sensing phosphatase (VSP) consists of a voltage sensor domain (VSD) and a cytoplasmic catalytic region (CCR), which is similar to phosphatase and tensin homolog (PTEN). How the VSD regulates the innate enzyme component of VSP remains unclear. Here, we took a combined approach that entailed the use of electrophysiology, fluorometry, and structural modeling to study the electrochemical coupling in Ciona intestinalis VSP. We found that two hydrophobic residues at the lowest part of S4 play an essential role in the later transition of VSD-CCR coupling. Voltage clamp fluorometry and disulfide bond locking indicated that S4 and its neighboring linker move as one helix (S4-linker helix) and approach the hydrophobic spine in the CCR, a structure located near the cell membrane and also conserved in PTEN. We propose that the hydrophobic spine operates as a hub for translating an electrical signal into a chemical one in VSP.

Keywords: Anap; hydrophobicity; phosphoinositide; voltage sensor domain; voltage-sensing phosphatase.

MeSH terms

  • Animals
  • Catalytic Domain
  • Cell Membrane / metabolism
  • Ciona intestinalis* / metabolism
  • Cytoplasm / metabolism
  • Phosphoric Monoester Hydrolases* / metabolism
  • Protein Domains

Substances

  • Phosphoric Monoester Hydrolases