title: The intermediate filament protein vimentin is a new target for epigallocatechin gallate.
abstract: Epigallocatechin gallate (EGCG) is the major active polyphenol in green tea. Protein interaction with EGCG is a critical step in the effects of EGCG on the regulation of various key proteins involved in signal transduction. We have identified a novel molecular target of EGCG using affinity chromatography, two-dimensional electrophoresis, and mass spectrometry for protein identification. Spots of interest were identified as the intermediate filament, vimentin. The identification was confirmed by Western blot analysis using an anti-vimentin antibody. Experiments using a pull-down assay with [3H]EGCG demonstrate binding of EGCG to vimentin with a Kd of 3.3 nm. EGCG inhibited phosphorylation of vimentin at serines 50 and 55 and phosphorylation of vimentin by cyclin-dependent kinase 2 and cAMP-dependent protein kinase. EGCG specifically inhibits cell proliferation by binding to vimentin. Because vimentin is important for maintaining cellular functions and is essential in maintaining the structure and mechanical integration of the cellular space, the inhibitory effect of EGCG on vimentin may further explain its anti-tumor-promoting effect.
authors.affiliation: Hormel Institute, University of Minnesota, Austin, Minnesota 55912, USA.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Ermakova
authors.forename: Bu Young
authors.initials: BY
authors.lastname: Choi
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Choi
authors.forename: Bong Seok
authors.initials: BS
authors.lastname: Kang
authors.forename: Ann M
authors.initials: AM
authors.lastname: Bode
authors.forename: Zigang
authors.initials: Z
authors.lastname: Dong
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D016588:Anticarcinogenic Agents / Q000494:pharmacology; D000970:Antineoplastic Agents / Q000494:pharmacology; D015153:Blotting, Western; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry*; D002460:Cell Line; D049109:Cell Proliferation; D002846:Chromatography, Affinity; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D015180:Electrophoresis, Gel, Two-Dimensional; D005419:Flavonoids / Q000737:chemistry; D005822:Genetic Vectors; D005982:Glutathione Transferase / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D020128:Inhibitory Concentration 50; D007700:Kinetics; D051379:Mice; D008856:Microscopy, Fluorescence; D008956:Models, Chemical; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry; D010636:Phenols / Q000737:chemistry; D010766:Phosphorylation; D059808:Polyphenols; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D012694:Serine / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014746:Vimentin / Q000737:chemistry* / Q000378:metabolism
chemical_list: D016588:Anticarcinogenic Agents; D000970:Antineoplastic Agents; D005419:Flavonoids; D010455:Peptides; D010636:Phenols; D059808:Polyphenols; D034741:RNA, Small Interfering; D014746:Vimentin; D012694:Serine; D002392:Catechin; C045651:epigallocatechin gallate; D005982:Glutathione Transferase; D017868:Cyclic AMP-Dependent Protein Kinases