title: Novel signaling pathways involved in sperm acquisition of fertilizing capacity.
abstract: Capacitation is a complex series of molecular events that occurs in sperm after epididymal maturation and confers on sperm the ability to fertilize an egg. This process can be mimicked in vitro in defined media, the composition of which is based on the electrolyte concentration of oviductal fluid. In most cases, capacitation media contain energy substrates, such as pyruvate, lactate and glucose, a cholesterol acceptor (usually serum albumin), NaHCO(3), Ca(2+), low K(+), and physiological Na(+) concentrations. The mechanism of action by which these compounds promote capacitation is poorly understood at the molecular level; however, some molecular events significant to the initiation of capacitation have been identified. For example, capacitation correlates with cholesterol efflux from the sperm plasma membrane, increased membrane fluidity, modulations in intracellular ion concentrations, hyperpolarization of the sperm plasma membrane and increased protein tyrosine phosphorylation. These molecular events are required for the subsequent induction of hyperactivation and the acrosome reaction. This review discusses the recent progress that has been made in elucidating mechanisms which regulate sperm capacitation.
authors.affiliation: Center for Recombinant Gamete Contraceptive Vaccinogens, Department of Cell Biology, University of Virginia, Charlottesville, VA 22908, USA. pv6j@virginia.edu
authors.forename: P E
authors.initials: PE
authors.lastname: Visconti
authors.forename: V A
authors.initials: VA
authors.lastname: Westbrook
authors.forename: O
authors.initials: O
authors.lastname: Chertihin
authors.forename: I
authors.initials: I
authors.lastname: Demarco
authors.forename: S
authors.initials: S
authors.lastname: Sleight
authors.forename: A B
authors.initials: AB
authors.lastname: Diekman
mesh_terms: D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D020013:Calcium Signaling; D002784:Cholesterol / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D017136:Ion Transport; D008297:Male; D008564:Membrane Potentials; D008954:Models, Biological; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology*; D013075:Sperm Capacitation / Q000502:physiology*; D013084:Sperm-Ovum Interactions / Q000502:physiology; D014443:Tyrosine / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D014443:Tyrosine; D002784:Cholesterol; D000242:Cyclic AMP