title: Phosphoproteomics study on the activated PKCδ-induced cell death.
abstract: The proteolytic activation of protein kinase Cδ (PKCδ) generates a catalytic fragment called PKCδ-CF, which induces cell death. However, the mechanisms underlying PKCδ-CF-mediated cell death are largely unknown. On the basis of an engineering leukemic cell line with inducible expression of PKCδ-CF, here we employ SILAC-based quantitative phosphoproteomics to systematically and dynamically investigate the overall phosphorylation events during cell death triggered by PKCδ-CF expression. Totally, 3000 phosphorylation sites were analyzed. Considering the fact that early responses to PKCδ-CF expression initiate cell death, we sought to identify pathways possibly related directly with PKCδ by further analyzing the data set of phosphorylation events that occur in the initiation stage of cell death. Interacting analysis of this data set indicates that PKCδ-CF triggers complicated networks to initiate cell death, and motif analysis and biochemistry verification reveal that several kinases in the downstream of PKCδ conduct these networks. By analysis of the specific sequence motif of kinase-substrate, we also find 59 candidate substrates of PKCδ from the up-regulated phosphopeptides, of which 12 were randomly selected for in vitro kinase assay and 9 were consequently verified as substrates of PKCδ. To our greatest understanding, this study provides the most systematic analysis of phosphorylation events initiated by the cleaved activated PKCδ, which would vastly extend the profound understanding of PKCδ-directed signal pathways in cell death. The MS data have been deposited to the ProteomeXchange with identifier PXD000225.
authors.affiliation: The Department of Pathophysiology and Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of National Ministry of Education, Shanghai Jiao Tong University School of Medicine (SJTU-SM) , Shanghai, P.R. China , 200025.
authors.forename: Li
authors.initials: L
authors.lastname: Xia
authors.forename: Tong-Dan
authors.initials: TD
authors.lastname: Wang
authors.forename: Shao-Ming
authors.initials: SM
authors.lastname: Shen
authors.forename: Meng
authors.initials: M
authors.lastname: Zhao
authors.forename: Han
authors.initials: H
authors.lastname: Sun
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.forename: Lu
authors.initials: L
authors.lastname: Xie
authors.forename: Zhao-Xia
authors.initials: ZX
authors.lastname: Wu
authors.forename: San-Feng
authors.initials: SF
authors.lastname: Han
authors.forename: Li-Shun
authors.initials: LS
authors.lastname: Wang
authors.forename: Guo-Qiang
authors.initials: GQ
authors.lastname: Chen
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis; D045744:Cell Line, Tumor; D016384:Consensus Sequence; D044842:Cullin Proteins / Q000378:metabolism; D063990:Gene Ontology; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D060066:Protein Interaction Maps; D051745:Protein Kinase C-delta / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D020543:Proteome / Q000235:genetics / Q000378:metabolism*; D040901:Proteomics; D015398:Signal Transduction
chemical_list: C114234:CUL4A protein, human; D044842:Cullin Proteins; D010750:Phosphoproteins; D020543:Proteome; C497258:PRKCD protein, human; D051745:Protein Kinase C-delta