Involvement of calcium-dependent protein kinase in rice (Oryza sativa L.) lamina inclination caused by brassinolide.
Promotive effect of brassinolide (BL) on green lamina inclination was concentration-dependent when excised rice (Oryza sativa L.) lamina was floated on BL solution under continuous light conditions. Protein kinase inhibitor staurosporine and Ca2+ channel blocker LaCl3 could completely, while Ca2+ chelator EGTA could partially inhibit the lamina inclination caused by BL. Two protein kinases with apparent molecular masses of 45 and 54 kDa were detected using an in-gel kinase assay with histone III-S as a substrate. In particular, the changes in 45 kDa protein kinase activity correlated with lamina inclination caused by BL. The 45 kDa kinase activity was inhibited by Ca2+ chelator EGTA, protein kinase inhibitor, staurosporine and calmodulin antagonist W-7. Therefore, this 45 kDa protein kinase was identified as a Ca2+ -dependent protein kinase (CDPK). Patterns of 2-dimensional PAGE after in vitro phosphorylation of crude extracts showed that the phosphorylation of 56 and 41 kDa proteins, which was Ca2+ -dependent, was strongly increased by BL treatment. These results suggested that CDPK and Ca2+ -dependent protein phosphorylation are involved in BL-induced rice lamina inclination.
Yang
G
G
Department of Molecular Genetics, National Institute of Agrobiological Resources, Tsukuba, 305-8602 Japan.
Komatsu
S
S
D060406:Brassinosteroids; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D002777:Cholestanols / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005030:Ethylenes / Q000494:pharmacology; D005875:Gibberellins / Q000494:pharmacology; D007210:Indoleacetic Acids / Q000494:pharmacology; D007811:Lanthanum / Q000494:pharmacology; D012275:Oryza / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D010766:Phosphorylation / Q000187:drug effects; D010937:Plant Growth Regulators / Q000494:pharmacology*; D018515:Plant Leaves / Q000187:drug effects* / Q000201:enzymology / Q000254:growth & development; D010940:Plant Proteins / Q000378:metabolism; D011494:Protein Kinases / Q000187:drug effects / Q000378:metabolism*; D019311:Staurosporine / Q000494:pharmacology; D013260:Steroids, Heterocyclic / Q000494:pharmacology*; D017871:Calcium-Calmodulin-Dependent Protein Kinases
D060406:Brassinosteroids; D002121:Calcium Channel Blockers; D002614:Chelating Agents; D002777:Cholestanols; D004533:Egtazic Acid; D004791:Enzyme Inhibitors; D005030:Ethylenes; D005875:Gibberellins; D007210:Indoleacetic Acids; D007811:Lanthanum; D010937:Plant Growth Regulators; D010940:Plant Proteins; D011494:Protein Kinases; D019311:Staurosporine; D013260:Steroids, Heterocyclic; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C028521:lanthanum chloride; C030737:indoleacetic acid; C036216:ethylene; C007842:gibberellic acid; C023623:brassinolide