PMID- 10887171
OWN - NLM
STAT- MEDLINE
DCOM- 20001103
LR  - 20210209
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 275
IP  - 38
DP  - 2000 Sep 22
TI  - Functional dichotomy of protein kinase C (PKC) in tumor necrosis factor-alpha 
      (TNF-alpha ) signal transduction in L929 cells. Translocation and inactivation of 
      PKC by TNF-alpha.
PG  - 29290-8
AB  - Tumor necrosis factor-alpha (TNF-alpha) is capable of inducing a variety of 
      biologic responses through multiple signaling pathways. Because of the potential 
      role of protein kinase C (PKC) in apoptosis, we examined the effects and 
      mechanisms of TNF-alpha on PKC regulation, specifically on PKC alpha. In L929 
      murine fibroblasts, TNF-alpha (0.5- 5 nm) caused potent inhibition of PKC alpha 
      activity and induced translocation of PKC alpha from the cytosol to the membrane. 
      Treatment of cells with TNF-alpha also induced dephosphorylation of PKC alpha as 
      detected by a mobility shift on SDS-polyacrylamide gel and inhibition of PKC 
      phosphorylation as probed by anti-phospho-PKC antibodies. Since PKC is activated 
      directly by diacylglycerol and inactivated indirectly by ceramide, we next 
      examined the roles of these lipid mediators in the regulation of PKC alpha. 
      Addition of TNF-alpha led to accumulation of both ceramide and diacylglycerol. 
      Fumonisin B(1), an inhibitor of ceramide synthase, and glutathione, an inhibitor 
      of neutral sphingomyelinase, both reversed the effect of TNF-alpha on PKC alpha 
      activity, suggesting that ceramide production is necessary for the action of 
      TNF-alpha. The diacylglycerol mimic phorbol 12-myristate 13-acetate was 
      sufficient to cause translocation of PKC alpha, but not the mobility shift. 
      Okadaic acid at 2 nm, a potent protein phosphatase inhibitor, blocked the effects 
      of TNF-alpha on PKC alpha activity, but not on PKC alpha translocation, thus 
      demonstrating that dephosphorylation and translocation are independent processes. 
      These results demonstrate that PKC alpha acts as a downstream target for 
      TNF-alpha and that different lipid-mediated pathways in TNF-alpha signaling lead 
      to opposing signals in the regulation of PKC alpha activity.
FAU - Lee, J Y
AU  - Lee JY
AD  - Department of Medicine, Duke University Medical Center,Durham, North Carolina 
      27710, USA.
FAU - Hannun, Y A
AU  - Hannun YA
FAU - Obeid, L M
AU  - Obeid LM
LA  - eng
GR  - 1R29-AG-12467/AG/NIA NIH HHS/United States
GR  - 5T32 AG00029/AG/NIA NIH HHS/United States
GR  - AG-16853-0/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Isoenzymes)
RN  - 0 (Tumor Necrosis Factor-alpha)
RN  - EC 2.7.11.13 (Prkca protein, mouse)
RN  - EC 2.7.11.13 (Protein Kinase C)
RN  - EC 2.7.11.13 (Protein Kinase C-alpha)
SB  - IM
MH  - Animals
MH  - Cell Line
MH  - Enzyme Activation/drug effects/physiology
MH  - Fibroblasts
MH  - Isoenzymes/*physiology
MH  - Mice
MH  - Protein Kinase C/*physiology
MH  - Protein Kinase C-alpha
MH  - *Signal Transduction/drug effects
MH  - Tumor Necrosis Factor-alpha/pharmacology/*physiology
EDAT- 2000/07/11 11:00
MHDA- 2001/02/28 10:01
CRDT- 2000/07/11 11:00
PHST- 2000/07/11 11:00 [pubmed]
PHST- 2001/02/28 10:01 [medline]
PHST- 2000/07/11 11:00 [entrez]
AID - S0021-9258(19)79403-4 [pii]
AID - 10.1074/jbc.M000170200 [doi]
PST - ppublish
SO  - J Biol Chem. 2000 Sep 22;275(38):29290-8. doi: 10.1074/jbc.M000170200.