Puce Stefania, Basile Giovanna, Bavestrello Giorgio, Bruzzone Santina, Cerrano Carlo, Giovine Marco, Arillo Attilio, Zocchi Elena
Dipartimento di Scienze del Mare, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy.
J Biol Chem. 2004 Sep 17;279(38):39783-8. doi: 10.1074/jbc.M405348200. Epub 2004 Jul 12.
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 --> increasing Ca(2+) --> regeneration is the first report of a complete signaling pathway in Eumetazoa involving a phytohormone.
环磷酸腺苷核糖（cADPR）是一种细胞内钙（Ca(2+)(i)）动员剂，参与从原生生物到高等植物和哺乳动物的基本细胞功能。植物干旱信号级联与海洋海绵温度传感途径之间的生化相似性表明，涉及植物激素脱落酸（ABA）、cADPR和Ca(2+)(i)的信号级联具有古老的进化起源。在总状真枝螅（水螅纲，刺胞动物门）中，外源添加的ABA通过蛋白激酶A（PKA）介导的磷酸化刺激ADP核糖基环化酶活性，并在黑暗中增加再生，使其达到在光照条件下观察到的水平。光照刺激内源性ABA合成，而植物ABA合成抑制剂氟啶酮则相反地抑制这种合成。在总状真枝螅中发现的光诱导再生信号级联：光→ABA增加→PKA→环化酶激活→cADPR增加→Ca(2+)增加→再生，这是关于后生动物中涉及植物激素的完整信号通路的首次报道。
