title: PKA activation in concert with ARIS and asterosap induces the acrosome reaction in starfish.
abstract: The acrosome reaction (AR) is a fundamental event for fertilization, which is induced in concert with acrosome reaction-inducing substance (ARIS) and asterosap, both of which are components of starfish egg jelly (EJ). During the AR, a spermatozoon undergoes a series of physiological changes, such as in intracellular cGMP concentration ([cGMP]i), pHi and intracellular Ca2+ concentration ([Ca2+]i). Affinity purification of cGMP-binding protein resulted in the isolation of a regulatory subunit of the cAMP-dependent protein kinase A (PKA), suggesting the involvement of a cAMP-dependent pathway in the AR. By using a cAMP enzyme immunoassay, [cAMP]i was found to increase in starfish spermatozoa when stimulated with ARIS and asterosap. ARIS could also increase the [cAMP]i in the presence of high pH seawater. Pretreatment of spermatozoa with two specific and cell-permeable PKA inhibitors, H89 and KT5720, prevented the induction of the AR in a concentration-dependent manner. These results suggest that PKA activity participates in the induction of the AR with ARIS and asterosap. To investigate this, we have cloned a gene that encodes a regulatory subunit of PKA that had been identified in starfish spermatozoa.
authors.affiliation: Department of Biosciences and Informatics, Keio University, Yokohama, Japan.
authors.forename: M Sadiqul
authors.initials: MS
authors.lastname: Islam
authors.forename: O
authors.initials: O
authors.lastname: Kawase
authors.forename: S
authors.initials: S
authors.lastname: Hase
authors.forename: M
authors.initials: M
authors.lastname: Hoshi
authors.forename: M
authors.initials: M
authors.lastname: Matsumoto
mesh_terms: D020101:Acrosome Reaction / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D047271:Asterias / Q000235:genetics / Q000502:physiology*; D001483:Base Sequence; D003001:Cloning, Molecular; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics; D004789:Enzyme Activation; D005260:Female; D005306:Fertilization / Q000502:physiology; D006023:Glycoproteins / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D036341:Intercellular Signaling Peptides and Proteins; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D021122:Protein Subunits; D012623:Seawater; D017386:Sequence Homology, Amino Acid
chemical_list: C067898:ARIS protein, Asterias amurensis; D018076:DNA, Complementary; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D021122:Protein Subunits; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D006152:Cyclic GMP