Mouse sperm K+ currents stimulated by pH and cAMP possibly coded by Slo3 channels

Pablo Martínez-López, Celia M. Santi, Claudia L. Treviño, Ana Y. Ocampo-Gutiérrez, Juan J. Acevedo, Arturo Alisio, Lawrence B. Salkoff, Alberto Darszon

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

Slo3 channels belong to the high conductance Slo K+ channel family. They are activated by voltage and intracellular alkalinization, and have a K+/Na+ permeability ratio (PK/PNa) of only approximately 5. Slo3 channels have only been found in mammalian sperm. Here we show that Slo3 channels expressed in Xenopus oocytes are also stimulated by elevated cAMP levels through PKA dependent phosphorylation. Capacitation, a maturational process required by mammalian sperm to enable them to fertilize eggs, involves intracellular alkalinization and an increase in cAMP. Our mouse sperm patch clamp recordings have revealed a K+ current that is time and voltage dependent, is activated by intracellular alkalinization, has a PK/PNa ≥ 5, is weakly blocked by TEA and is very sensitive to Ba2+. This current is also stimulated by cAMP. All of these properties match those displayed by heterologously expressed Slo3 channels, suggesting that the native current we observe in sperm is indeed carried by Slo3 channels.

Original languageEnglish
Pages (from-to)204-209
Number of pages6
JournalBiochemical and Biophysical Research Communications
Volume381
Issue number2
DOIs
StatePublished - Apr 3 2009

Keywords

  • Capacitation
  • Potassium currents
  • Slo channels
  • Slo3 channels
  • Sperm
  • cAMP
  • pH regulation

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