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Updated: Aug 7, 2026

Recording Electrical Currents across the Plasma Membrane of Mammalian Sperm Cells
Published on: February 14, 2021
Evidence for a secretory pathway Ca2+-ATPase in sea urchin spermatozoa
Herath Jayantha Gunaratne1, Victor D Vacquier
1Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA 92093-0202, USA. hgunarat@ucsd.edu
Abstract:
Plasma membrane, sarco-endoplasmic reticulum and secretory pathway Ca2+-ATPases (designated PMCA, SERCA and SPCA) regulate intracellular Ca2+ in animal cells. The presence of PMCA, and the absence of SERCA, in sea urchin sperm is known. By using inhibitors of Ca2+-ATPases, we now show the presence of SPCA and Ca2+ store in sea urchin sperm, which refills by SPCA-type pumps. Immunofluorescence shows SPCA localizes to the mitochondrion. Ca2+ measurements reveal that approximately 75% of Ca2+ extrusion is by Ca2+ ATPases and 25% by Na+ dependent Ca2+ exchanger/s. Bisphenol, a Ca2+ ATPase inhibitor, completely blocks the acrosome reaction, indicating the importance of Ca2+-ATPases in fertilization.
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