Particulate and soluble adenylyl cyclases participate in the sperm acrosome reaction.
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.
Beltrán
Carmen
C
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
Vacquier
Victor D
VD
Moy
Gary
G
Chen
Yanqiu
Y
Buck
Jochen
J
Levin
Lonny R
LR
Darszon
Alberto
A
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
D001639:Bicarbonates; D000262:Adenylyl Cyclases