PKCalpha is involved in phorbol ester TPA-mediated stabilization of p14ARF.
We generated A21-13 cells expressing p14(ARF) in the presence of doxycycline in order to examine the stability of p14(ARF) protein. The effects of proteasome inhibitor MG132 on p14(ARF) protein stabilization were detectable using our experimental procedure. Introduction of mutant p53 did not affect MG132-mediated p14(ARF) protein stabilization. We found that phorbol ester TPA (12-o-tetradecanoyl-phorbol 13-acetate) stabilized p14(ARF) protein and that p53 status had no effect on TPA-mediated stabilization. TPA-mediated stabilization was abolished by staurosporine but not by lovastatin or U0126. We further investigated which isoforms of PKC were involved in TPA-mediated p14(ARF) stabilization using short-interference RNA. Knockdown of PKCalpha, but not PKCdelta, attenuated TPA-mediated p14(ARF) stabilization. These findings suggest that PKCalpha is involved in TPA-mediated stabilization of p14(ARF) protein, and this effect of TPA was not affected by the Ras/MAPK pathway or p53 status. Our results are indicative of a novel role of PKC in p14(ARF) protein stability.
Inoue
Rie
R
Second Department of Pathology, Mie University School of Medicine, 2-174 Edobashi, Tsu, Mie 514-8507, Japan. rinoue@clin.medic.mie-u.ac.jp
Shiraishi
Taizo
T
D002070:Butadienes / Q000494:pharmacology; D045744:Cell Line, Tumor; D004318:Doxycycline / Q000494:pharmacology; D016158:Genes, p53 / Q000502:physiology; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008148:Lovastatin / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors; D020935:MAP Kinase Signaling System / Q000502:physiology; D009570:Nitriles / Q000494:pharmacology; D061988:Proteasome Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D016283:Proto-Oncogene Proteins p21(ras) / Q000037:antagonists & inhibitors; D034741:RNA, Small Interfering / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D025803:Tumor Suppressor Protein p14ARF / Q000378:metabolism*
D002070:Butadienes; D007976:Leupeptins; D009570:Nitriles; D061988:Proteasome Inhibitors; D034741:RNA, Small Interfering; D025803:Tumor Suppressor Protein p14ARF; C113580:U 0126; D008148:Lovastatin; C496628:PRKCA protein, human; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D020930:MAP Kinase Kinase Kinases; C501009:HRAS protein, human; D016283:Proto-Oncogene Proteins p21(ras); D019311:Staurosporine; D004318:Doxycycline; D013755:Tetradecanoylphorbol Acetate; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde