title: Particulate and soluble adenylyl cyclases participate in the sperm acrosome reaction.
abstract: cAMP is important in sea urchin sperm signaling, yet the molecular nature of the adenylyl cyclases (ACs) involved remained unknown. These cells were recently shown to contain an ortholog of the mammalian soluble adenylyl cyclase (sAC). Here, we show that sAC is present in the sperm head and as in mammals is stimulated by bicarbonate. The acrosome reaction (AR), a process essential for fertilization, is influenced by the bicarbonate concentration in seawater. By using functional assays and immunofluorescence techniques we document that sea urchin sperm also express orthologs of multiple isoforms of transmembrane ACs (tmACs). Our findings employing selective inhibitors for each class of AC indicate that both sAC and tmACs participate in the sperm acrosome reaction.
authors.affiliation: Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos CP 62250, Mexico. beltran@ibt.unam.mx
authors.forename: Carmen
authors.initials: C
authors.lastname: Beltrán
authors.forename: Victor D
authors.initials: VD
authors.lastname: Vacquier
authors.forename: Gary
authors.initials: G
authors.lastname: Moy
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Chen
authors.forename: Jochen
authors.initials: J
authors.lastname: Buck
authors.forename: Lonny R
authors.initials: LR
authors.lastname: Levin
authors.forename: Alberto
authors.initials: A
authors.lastname: Darszon
mesh_terms: D000177:Acrosome / Q000187:drug effects / Q000502:physiology*; D020101:Acrosome Reaction / Q000187:drug effects / Q000502:physiology*; D000262:Adenylyl Cyclases / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001639:Bicarbonates / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D008297:Male; D012617:Sea Urchins / Q000502:physiology*; D012995:Solubility
chemical_list: D001639:Bicarbonates; D000262:Adenylyl Cyclases