TY - JOUR
T1 - Mouse sperm K+ currents stimulated by pH and cAMP possibly coded by Slo3 channels
AU - Martínez-López, Pablo
AU - Santi, Celia M.
AU - Treviño, Claudia L.
AU - Ocampo-Gutiérrez, Ana Y.
AU - Acevedo, Juan J.
AU - Alisio, Arturo
AU - Salkoff, Lawrence B.
AU - Darszon, Alberto
N1 - Funding Information:
Supported by: NIH Grants R01 HD038082-07A1 (to PEV and AD), 1R21HD056444-01A1 (to CS) and R01 GM067154-01A1 (to LS) and CONACyT-Mexico, 49113 (to AD), DGAPA/UNAM IN211809 (to AD) and IN204109 (to CT), and the Wellcome Trust (to AD). We thank Elizabeth Mata, Marcela Ramírez and Shirley Ainsworth for technical assistance.
PY - 2009/4/3
Y1 - 2009/4/3
N2 - 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.
AB - 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.
KW - Capacitation
KW - Potassium currents
KW - Slo channels
KW - Slo3 channels
KW - Sperm
KW - cAMP
KW - pH regulation
UR - http://www.scopus.com/inward/record.url?scp=61849099356&partnerID=8YFLogxK
U2 - 10.1016/j.bbrc.2009.02.008
DO - 10.1016/j.bbrc.2009.02.008
M3 - Article
C2 - 19338774
AN - SCOPUS:61849099356
SN - 0006-291X
VL - 381
SP - 204
EP - 209
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -