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The effect of IAA on phosphorylation of plasma proteins in wheat coleoptiles

Wu Haiming, Wang Ningning, Yu Ziran, Zhu Liangji

Biochemistry and Molecular Biology Department of Nankai University.Tianjing 300071

Abstract

Protein kinases and protein phosphatases play key roles in signal transduction. Many factors regulate enzyme activities by changing the phosphorylation level of them. Protein kinase activity was observed in plasma membrane of wheat coleoptiles. Activity of this kinase is Ca~(2+)-dependent. Treating with IAA increased the kinase activity. The phosphorylation of proteins with molecular weight 132, 100, 87, 72, 50 and 35 kD was enhanced. IAA also enhanced the autophosphorylation of protein kinases with MW 125 and 89 kD. LaCl_(3), as an inhibitor of calcium ion channel, diminished of calcium ion channel, diminished the influences of IAA. It seems possible that Ca~(2+)-dependent protein kinase functions in calcium-regulated signal transduction processes in IAA-induced elongation of wheat coleoptiles through their responses to changes in concentration of cytosolic calcium.

Key words: IAA;Wheat coleoptiles;Protein phosphorylation;Protein kinase;Ca~(2+) ion channel

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Citing This Article：

Wu Haiming, Wang Ningning, Yu Ziran, Zhu Liangji. The effect of IAA on phosphorylation of plasma proteins in wheat coleoptiles. Acta Physiol Sin 1999; 51 (4): (in Chinese with English abstract).