Abscisic acid signaling through cyclic ADP-ribose in hydroid regeneration.
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.
Puce
Stefania
S
Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
Basile
Giovanna
G
Bavestrello
Giorgio
G
Bruzzone
Santina
S
Cerrano
Carlo
C
Giovine
Marco
M
Arillo
Attilio
A
Zocchi
Elena
E
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*
D010937:Plant Growth Regulators; D036563:Cyclic ADP-Ribose; D000040:Abscisic Acid; D017868:Cyclic AMP-Dependent Protein Kinases; D036541:ADP-ribosyl Cyclase