Activation of mammalian sperm motility by regulation of microtubule sliding via cyclic adenosine 5'-monophosphate-dependent phosphorylation.
Bicarbonate was found to be essential for activating live mouse sperm motility. The activated sperm flagella exhibited high beat frequency, high swimming velocity, and large principal and reverse bends. To gain further insight into the bicarbonate-triggered activation mechanism, the microtubule sliding characteristics of the activated versus the nonactivated sperm flagella were compared by use of demembranated sperm. We found that the effects of bicarbonate on live sperm were identical with the effects of cAMP on demembranated sperm both in microtubule sliding velocity and in sliding disintegration pattern. Furthermore, autoradiography revealed that the activation of mouse sperm motility was associated with cAMP-dependent phosphorylation of a 65-kDa flagellar protein. The results demonstrated that bicarbonate-triggered activation of mouse sperm motility was closely coupled with the regulation of microtubule sliding via cAMP-dependent phosphorylation.
Department of Biology, College of Arts and Sciences, University of Tokyo, Japan.
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Okuno
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002462:Cell Membrane / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D008870:Microtubules / Q000187:drug effects / Q000502:physiology*; D010766:Phosphorylation; D013081:Sperm Motility / Q000187:drug effects; D013082:Sperm Tail / Q000187:drug effects / Q000502:physiology; D013094:Spermatozoa / Q000648:ultrastructure*
D001639:Bicarbonates; D000255:Adenosine Triphosphate; D000242:Cyclic AMP