title: Programmed cell death protein 5 (PDCD5) is phosphorylated by CK2 in vitro and in 293T cells.
abstract: CK2 is a multifunctional kinase, involved in cell growth, apoptosis, DNA integrity preservation, viral infection, and many other biological processes. Based on an analysis of phosphopeptides database derived from phosphoproteomic studies we previously identified a list of potential new CK2 substrates, including, among others, Programmed Cell Death 5 (PDCD5), a protein involved in cell death and down-regulated in different forms of human tumors. Here we provide experimental evidence that PDCD5 is indeed a bona fide substrate of CK2. PDCD5 is phosphorylated in vitro by both CK2alpha subunit and by the CK2 holoenzyme at a residue, S118, which is found phosphorylated in vivo. We also show that PDCD5 is phosphorylated by CK2 in 293T cells. Transfection of the non-phosphorylatable mutant (S118A) impairs the PDCD5 acceleration of either doxorubimicin- or UV-induced apoptosis in U2OS cells. Our results suggest a functional link between the CK2 phosphorylation and the apoptotic potential of PDCD5.
authors.affiliation: Department of Biological Chemistry, University of Padova, Viale G. Colombo 3, Padua, Italy. mauro.salvi@unipd.it
authors.forename: Mauro
authors.initials: M
authors.lastname: Salvi
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.forename: Yingyu
authors.initials: Y
authors.lastname: Chen
authors.forename: Anna
authors.initials: A
authors.lastname: Cabrelle
authors.forename: Stefania
authors.initials: S
authors.lastname: Sarno
authors.forename: Lorenzo A
authors.initials: LA
authors.lastname: Pinna
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism*; D047390:Casein Kinase II / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D016415:Sequence Alignment; D012694:Serine / Q000235:genetics / Q000378:metabolism
chemical_list: D051017:Apoptosis Regulatory Proteins; D009363:Neoplasm Proteins; C117283:PDCD5 protein, human; D012694:Serine; D047390:Casein Kinase II