title: Abscisic acid signaling through cyclic ADP-ribose in hydroid regeneration.
abstract: Cyclic ADP-ribose (cADPR) is an intracellular calcium (Ca(2+)(i)) mobilizer involved in fundamental cell functions from protists to higher plants and mammals. Biochemical similarities between the drought-signaling cascade in plants and the temperature-sensing pathway in marine sponges suggest an ancient evolutionary origin of a signaling cascade involving the phytohormone abscisic acid (ABA), cADPR, and Ca(2+)(i). In Eudendrium racemosum (Hydrozoa, Cnidaria), exogenously added ABA stimulated ADP-ribosyl cyclase activity via a protein kinase A (PKA)-mediated phosphorylation and increased regeneration in the dark to levels observed under light conditions. Light stimulated endogenous ABA synthesis, which was conversely inhibited by the inhibitor of plant ABA synthesis Fluridone. The signal cascade of light-induced regeneration uncovered in E. racemosum: light --> increasing ABA --> PKA --> cyclase activation --> increasing [cADPR](i) --> increasing [Ca(2+)](i) --> regeneration is the first report of a complete signaling pathway in Eumetazoa involving a phytohormone.
authors.affiliation: Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Puce
authors.forename: Giovanna
authors.initials: G
authors.lastname: Basile
authors.forename: Giorgio
authors.initials: G
authors.lastname: Bavestrello
authors.forename: Santina
authors.initials: S
authors.lastname: Bruzzone
authors.forename: Carlo
authors.initials: C
authors.lastname: Cerrano
authors.forename: Marco
authors.initials: M
authors.lastname: Giovine
authors.forename: Attilio
authors.initials: A
authors.lastname: Arillo
authors.forename: Elena
authors.initials: E
authors.lastname: Zocchi
mesh_terms: D036541:ADP-ribosyl Cyclase / Q000378:metabolism; D000040:Abscisic Acid / Q000378:metabolism*; D000818:Animals; D002455:Cell Division / Q000502:physiology; D036563:Cyclic ADP-Ribose / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D003624:Darkness; D037402:Hydrozoa / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D008027:Light; D010937:Plant Growth Regulators / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*
chemical_list: D010937:Plant Growth Regulators; D036563:Cyclic ADP-Ribose; D000040:Abscisic Acid; D017868:Cyclic AMP-Dependent Protein Kinases; D036541:ADP-ribosyl Cyclase