Polarized PtdIns(4,5)P2 distribution mediated by a voltage-sensing phosphatase (VSP) regulates sperm motility

Proc Natl Acad Sci U S A. 2019 Dec 17;116(51):26020-26028. doi: 10.1073/pnas.1916867116. Epub 2019 Nov 27.

Abstract

The voltage-sensing phosphatase (VSP) is a unique protein that shows voltage-dependent phosphoinositide phosphatase activity. Here we report that VSP is activated in mice sperm flagellum and generates a unique subcellular distribution pattern of PtdIns(4,5)P2 Sperm from VSP-/- mice show more Ca2+ influx upon capacitation than VSP+/- mice and abnormal circular motion. VSP-deficient sperm showed enhanced activity of Slo3, a PtdIns(4,5)P2-sensitive K+ channel, which selectively localizes to the principal piece of the flagellum and indirectly enhances Ca2+ influx. Most interestingly, freeze-fracture electron microscopy analysis indicates that normal sperm have much less PtdIns(4,5)P2 in the principal piece than in the midpiece of the flagellum, and this polarized PtdIns(4,5)P2 distribution disappeared in VSP-deficient sperm. Thus, VSP appears to optimize PtdIns(4,5)P2 distribution of the principal piece. These results imply that flagellar PtdIns(4,5)P2 distribution plays important roles in ion channel regulation as well as sperm motility.

Keywords: PtdIns(4,5)P2; membrane potential; sperm; voltage-sensing phosphatase.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium Channels / metabolism
  • Flagella / metabolism
  • Ion Channels / metabolism*
  • Large-Conductance Calcium-Activated Potassium Channels / metabolism
  • Male
  • Membrane Potentials / physiology
  • Mice
  • Mice, Knockout
  • Phosphatidylinositol 4,5-Diphosphate / chemistry*
  • Phosphatidylinositol 4,5-Diphosphate / metabolism*
  • Phosphoric Monoester Hydrolases / genetics
  • Phosphoric Monoester Hydrolases / metabolism*
  • Sperm Motility / physiology*
  • Sperm Tail / metabolism
  • Spermatozoa / metabolism

Substances

  • Calcium Channels
  • Ion Channels
  • Kcnu1 protein, mouse
  • Large-Conductance Calcium-Activated Potassium Channels
  • Phosphatidylinositol 4,5-Diphosphate
  • Phosphoric Monoester Hydrolases