TY - JOUR
T1 - The Ca2+-activated K+ current of human sperm is mediated by Slo3
AU - Brenker, Christoph
AU - Zhou, Yu
AU - Müller, Astrid
AU - Echeverry, Fabio Andres
AU - Trötschel, Christian
AU - Poetsch, Ansgar
AU - Xia, Xiao Ming
AU - Bönigk, Wolfgang
AU - Lingle, Christopher J.
AU - Kaupp, U. Benjamin
AU - Strünker, Timo
PY - 2014/3/26
Y1 - 2014/3/26
N2 - Sperm are equipped with a unique set of ion channels that orchestrate fertilization. In mouse sperm, the principal K+ current (IKSper) is carried by the Slo3 channel, which sets the membrane potential (Vm) in a strongly pHi-dependent manner. Here, we show that IKSper in human sperm is activated weakly by pHi and more strongly by Ca2+. Correspondingly, Vm is strongly regulated by Ca2+ and less so by pHi. We find that inhibitors of Slo3 suppress human IKSper, and we identify the Slo3 protein in the flagellum of human sperm. Moreover, heterologously expressed human Slo3, but not mouse Slo3, is activated by Ca2+ rather than by alkaline pHi; current-voltage relations of human Slo3 and human IKSper are similar. We conclude that Slo3 represents the principal K+ channel in human sperm that carries the Ca2+-activated IKSper current. We propose that, in human sperm, the progesterone-evoked Ca2+ influx carried by voltage-gated CatSper channels is limited by Ca2+-controlled hyperpolarization via Slo3.
AB - Sperm are equipped with a unique set of ion channels that orchestrate fertilization. In mouse sperm, the principal K+ current (IKSper) is carried by the Slo3 channel, which sets the membrane potential (Vm) in a strongly pHi-dependent manner. Here, we show that IKSper in human sperm is activated weakly by pHi and more strongly by Ca2+. Correspondingly, Vm is strongly regulated by Ca2+ and less so by pHi. We find that inhibitors of Slo3 suppress human IKSper, and we identify the Slo3 protein in the flagellum of human sperm. Moreover, heterologously expressed human Slo3, but not mouse Slo3, is activated by Ca2+ rather than by alkaline pHi; current-voltage relations of human Slo3 and human IKSper are similar. We conclude that Slo3 represents the principal K+ channel in human sperm that carries the Ca2+-activated IKSper current. We propose that, in human sperm, the progesterone-evoked Ca2+ influx carried by voltage-gated CatSper channels is limited by Ca2+-controlled hyperpolarization via Slo3.
UR - http://www.scopus.com/inward/record.url?scp=84898749044&partnerID=8YFLogxK
U2 - 10.7554/eLife.01438
DO - 10.7554/eLife.01438
M3 - Article
C2 - 24670955
AN - SCOPUS:84898749044
SN - 2050-084X
VL - 2014
JO - eLife
JF - eLife
IS - 3
M1 - e01438
ER -