Work

KSper, a pH-sensitive K + current that controls sperm membrane potential

Year: 2007

Type: article

Abstract: Mature mammalian spermatozoa are quiescent in the male reproductive tract. Upon ejaculation and during their transit through the female reproductive tract, they undergo changes that enable them to fertilize the egg. During this process of capacitation, they acquire progressive motility, develop hyperactivated motility, and are readied for the acrosome reaction. All of these processes are regulated by intracellular pH. In the female reproductive tract, the spermatozoan cytoplasm alkalinizes, which in turn activates a Ca2+-selective current (I(CatSper)) required for hyperactivated motility. Here, we show that alkalinization also has a dramatic effect on membrane potential, producing a rapid hyperpolarization. This hyperpolarization is primarily mediated by a weakly outwardly rectifying K+ current (I(KSper)) originating from the principal piece of the sperm flagellum. Alkalinization activates the pH(i)-sensitive I(KSper), setting the membrane potential to negative potentials where Ca2+ entry via I(CatSper) is maximized. I(KSper) is one of two dominant ion currents of capacitated sperm cells.

Source: Proceedings of the National Academy of Sciences

DOI: 10.1073/pnas.0702018104

Authors: Betsy Navarro, Yuriy Kirichok, David E. Clapham

Institutions: Boston Children's Hospital, Howard Hughes Medical Institute, Harvard University, University of California, San Francisco

Language: English

Topic: Sperm and Testicular Function

Subfield: Reproductive Medicine

Field: Medicine

Domain: Health Sciences

Open Access status: green

Funders: National Institutes of Health, U.S. Public Health Service, Eunice Kennedy Shriver National Institute of Child Health and Human Development

Awards: G4051201072, Novel CatSper3 and CatSper4 Ion Channel Genes in Sperm