title: PKCδ-mediated phosphorylation of BAG3 at Ser187 site induces epithelial-mesenchymal transition and enhances invasiveness in thyroid cancer FRO cells.
abstract: Protein kinase C delta (PKCδ) is a serine (Ser)/threonine kinase, which regulates numerous cellular processes, including proliferation, differentiation, migration and apoptosis. In the current study, Chinese hamster ovary cells were transfected with either a constitutively activated PKCδ or a dominant negative PKCδ, phosphoprotein enrichment, two-dimensional difference gel electrophoresis and mass spectrometry was combined to globally identified candidates of PKCδ cascade. We found that Bcl-2 associated athanogene 3 (BAG3) was one of the targets of PKCδ cascade, and BAG3 interacted with PKCδ in vivo. In addition, we clarified that BAG3 was phosphorylate at Ser187 site in a PKCδ-dependent manner in vivo. BAG3 has been implicated in multiple cellular functions, including proliferation, differentiation, apoptosis, migration, invasion, macroautophagy and so on. We generated wild-type (WT)-, Ser187Ala (S187A)- or Ser187Asp (S187D)-BAG3 stably expressing FRO cells, and noticed that phosphorylation state of BAG3 influenced FRO morphology. Finally, for the first time, we showed that BAG3 was implicated in epithelial-mesenchymal transition (EMT) procedure, and phosphorylation state at Ser187 site had a critical role in EMT regulation by BAG3. Collectively, the current study indicates that BAG3 is a novel substrate of PKCδ, and PKCδ-mediated phosphorylation of BAG3 is implicated in EMT and invasiveness of thyroid cancer cells.
authors.affiliation: 1] Department of Biochemistry and Molecular Biology, China Medical University, Shenyang, China [2] Key Laboratory of Cell Biology, Ministry of Public Health and Key Laboratory of Medical Cell Biology, Ministry of Education, China Medical University, Shenyang, China.
authors.forename: N
authors.initials: N
authors.lastname: Li
authors.forename: Z-X
authors.initials: ZX
authors.lastname: Du
authors.forename: Z-H
authors.initials: ZH
authors.lastname: Zong
authors.forename: B-Q
authors.initials: BQ
authors.lastname: Liu
authors.forename: C
authors.initials: C
authors.lastname: Li
authors.forename: Q
authors.initials: Q
authors.lastname: Zhang
authors.forename: H-Q
authors.initials: HQ
authors.lastname: Wang
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D016466:CHO Cells; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D003412:Cricetulus; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D051745:Protein Kinase C-delta / Q000235:genetics / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C414431:BAG3 protein, human; D012694:Serine; D051745:Protein Kinase C-delta