Protein kinase Cdelta is responsible for constitutive and DNA damage-induced phosphorylation of Rad9.
The mammalian homolog of the Schizosaccharomyces pombe Rad9 is involved in checkpoint signaling and the induction of apoptosis. While the mechanisms responsible for the regulation of human Rad9 (hRad9) are not known, hRad9 is subject to hyperphosphorylation in the response of cells to DNA damage. The present results demonstrate that protein kinase Cdelta (PKCdelta) associates with Rad9 and that DNA damage induces this interaction. PKCdelta phosphorylates hRad9 in vitro and in cells exposed to genotoxic agents. The functional significance of the interaction between hRad9 and PKCdelta is supported by the finding that activation of PKCdelta is necessary for formation of the Rad9-Hus1-Rad1 complex. We also show that PKCdelta is required for binding of hRad9 to Bcl-2. In concert with these results, inhibition of PKCdelta attenuates Rad9-mediated apoptosis. These findings demonstrate that PKCdelta is responsible for the regulation of Rad9 in the Hus1-Rad1 complex and in the apoptotic response to DNA damage.
Yoshida
Kiyotsugu
K
Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115, USA.
Wang
Hong-Gang
HG
Miki
Yoshio
Y
Kufe
Donald
D
D017209:Apoptosis; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000187:drug effects / Q000378:metabolism*; D016923:Cell Death; D002460:Cell Line; D003561:Cytarabine / Q000494:pharmacology; D004249:DNA Damage; D004268:DNA-Binding Proteins; D004789:Enzyme Activation; D049452:Green Fluorescent Proteins; D006801:Humans; D008164:Luminescent Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism*; D051745:Protein Kinase C-delta; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins; D020298:U937 Cells
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D008164:Luminescent Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D025521:Tumor Suppressor Proteins; D003561:Cytarabine; C069930:rad9 protein; D049452:Green Fluorescent Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; C497258:PRKCD protein, human; D011493:Protein Kinase C; D051745:Protein Kinase C-delta