文章基本信息

标题：Biochemical Characterization of Epigallocatechin-3-gallate as an Effective Stimulator for the Phosphorylation of Its Binding Proteins by Glycogen Synthase Kinase-3β in Vitro
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作者：Sayaka Miyai ; Akira Yamaguchi ; Tetsumi Iwasaki 等
期刊名称：Biological and Pharmaceutical Bulletin
印刷版ISSN：0918-6158
电子版ISSN：1347-5215
出版年度：2010
卷号：33
期号：12
页码：1932-1937
DOI：10.1248/bpb.33.1932
出版社：The Pharmaceutical Society of Japan
摘要：The stimulatory and inhibitory effects of epigallocatechin-3-gallate (EGCG) and its related two compounds (luteolin and quercetin) on the phosphorylation of four proteins [bovine myelin basic protein (bMBP), human recombinant tau protein (hrTP), human recombinant vimentin (hrVM) and rat collapsin response mediator protein-2 (rCRMP-2)] by glycogen synthase kinase-3β (GSK-3β) were comparatively determined in vitro . We found that (i) EGCG, not quercetin and luteolin, highly stimulated the GSK-3β-mediated phosphorylation of hrTP and significantly stimulated the phosphorylation of bMBP and hrVM by the kinase; (ii) these three polyphenols inhibited dose-dependently the phosphorylation of rCRMP-2 by GSK-3β; (iii) only EGCG significantly enhanced autophosphorylation of GSK-3β; and (iv) EGCG had a binding-affinity with two basic proteins (bMBP and hrTP) and a low affinity with rCRMP-2 rather than hrVM in vitro . In addition, the binding of EGCG to these two basic proteins induced to highly stimulate their phosphorylation, including novel potent sites for GSK-3β, and to significantly reduce the K _m value and increase the V _max value of these two substrate proteins for the kinase in vitro . These results provided here suggest that EGCG acts as an effective stimulator for the GSK-3β-mediated phosphorylation of its binding proteins containing EGCG-inducible phosphorylation sites for the kinase in vitro .
关键词：epigallocatechin-3-gallate;glycogen synthase kinase-3β;myelin basic protein;tau protein;collapsin response mediator protein-2 and vimentin