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Updated: Jan 3, 2026

Recording Electrical Currents across the Plasma Membrane of Mammalian Sperm Cells
Published on: February 14, 2021
Polarized PtdIns(4,5)P2 distribution mediated by a voltage-sensing phosphatase (VSP) regulates sperm motility
Takafumi Kawai1, Haruhiko Miyata2, Hiroki Nakanishi3
1Graduate School of Medicine, Osaka University, Suita 565-0871, Japan.
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.
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