CATSPER channel-mediated Ca2+ entry into mouse sperm triggers a tail-to-head propagation.
Many Ca(2+) channel proteins have been detected in mammalian sperm, but only the four CATSPER channels have been clearly shown to be required for male fertility. Ca(2+) entry through the principal piece-localized CATSPER channels has been implicated in the activation of hyperactivated motility. In the present study, we show that the Ca(2+) entry also triggers a tail-to-head Ca(2+) propagation in the mouse sperm. When activated with 8-Br-cAMP, 8-Br-cGMP, or alkaline depolarization, a CATSPER-dependent increase in intracellular Ca(2+) concentration starts in the principal piece, propagates through the midpiece, and reaches the head in a few seconds. The Ca(2+) propagation through the midpiece leads to a Ca(2+)-dependent increase in NADH fluorescence. In addition, CatSper1-mutant sperm have lower intracellular ATP levels than wild-type sperm. Thus, a Ca(2+) influx in the principal piece through CATSPER channels can not only initiate hyperactivated motility, but can also trigger a tail-to-head Ca(2+) propagation that leads to an increase in [NADH] and may regulate ATP homeostasis.
Xia
Jingsheng
J
Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA.
Reigada
David
D
Mitchell
Claire H
CH
Ren
Dejian
D
D020101:Acrosome Reaction / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D013075:Sperm Capacitation / Q000502:physiology; D013081:Sperm Motility / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism / Q000502:physiology*
D015220:Calcium Channels; C488642:Catsper1 protein, mouse; D000255:Adenosine Triphosphate; D002118:Calcium