title: HSP70 decreases receptor-dependent phosphorylation of Smad2 and blocks TGF-β-induced epithelial-mesenchymal transition.
abstract: Smad2 and Smad3, the intracellular mediators of transforming growth factor β (TGF-β) signaling, are directly phosphorylated by the activated type I receptor kinase, and then shuttle from the cytoplasm into the nucleus to regulate target gene expression. Here, we report that the 70-kDa heat-shock protein (HSP70) interacts with Smad2 and decreases TGF-β signal transduction. Ectopic expression of HSP70 prevents receptor-dependent phosphorylation and nuclear translocation of Smad2, and blocks TGF-β-induced epithelial-mesenchymal transition (EMT) in HaCat cells. Our findings reveal an essential role of HSP70 in TGF-β-induced epithelial-mesenchymal transition (EMT) by impeding Smad2 phosphorylation.
authors.affiliation: College of Life Sciences, Hebei University, Baoding 071002, China.
authors.forename: Yihao
authors.initials: Y
authors.lastname: Li
authors.forename: Xianjiang
authors.initials: X
authors.lastname: Kang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018929:Cell Culture Techniques; D058750:Epithelial-Mesenchymal Transition; D057809:HEK293 Cells; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction; D051899:Smad2 Protein / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology; D029961:Zebrafish Proteins / Q000378:metabolism*
chemical_list: D018840:HSP70 Heat-Shock Proteins; D034741:RNA, Small Interfering; D051899:Smad2 Protein; D016212:Transforming Growth Factor beta; D029961:Zebrafish Proteins; C497786:smad2 protein, zebrafish