RRC ID 1304
Author Kajimoto T, Shirai Y, Sakai N, Yamamoto T, Matsuzaki H, Kikkawa U, Saito N.
Title Ceramide-induced apoptosis by translocation, phosphorylation, and activation of protein kinase Cdelta in the Golgi complex.
Journal J Biol Chem
Abstract Protein kinase C (PKC), a Ca(2+)/phospholipid-dependent protein kinase, is known as a key enzyme in various cellular responses, including apoptosis. However, the functional role of PKC in apoptosis has not been clarified. In this study, we focused on the involvement of PKCdelta in ceramide-induced apoptosis in HeLa cells and examined the importance of spatiotemporal activation of the specific PKC subtype in apoptotic events. Ceramide-induced apoptosis was inhibited by the PKCdelta-specific inhibitor rottlerin and also was blocked by knockdown of endogenous PKCdelta expression using small interfering RNA. Ceramide induced the translocation of PKCdelta to the Golgi complex and the concomitant activation of PKCdelta via phosphorylation of Tyr(311) and Tyr(332) in the hinge region of the enzyme. Unphosphorylatable PKCdelta (mutants Y311F and Y332F) could translocate to the Golgi complex in response to ceramide, suggesting that tyrosine phosphorylation is not necessary for translocation. However, ceramide failed to activate PKCdelta lacking the C1B domain, which did not translocate to the Golgi complex, but could be activated by tyrosine phosphorylation. These findings suggest that ceramide translocates PKCdelta to the Golgi complex and that PKCdelta is activated by tyrosine phosphorylation in the compartment. Furthermore, we utilized species-specific knockdown of PKCdelta by small interfering RNA to study the significance of phosphorylation of Tyr(311) and Tyr(332) in PKCdelta for ceramide-induced apoptosis and found that phosphorylation of Tyr(311) and Tyr(332) is indispensable for ceramide-induced apoptosis. We demonstrate here that the targeting mechanism of PKCdelta, dual regulation of both its activation and translocation to the Golgi complex, is critical for the ceramide-induced apoptotic event.
Volume 279(13)
Pages 12668-76
Published 2004-3-26
DOI 10.1074/jbc.M312350200
PII M312350200
PMID 14715667
MeSH Acetophenones / pharmacology Animals Apoptosis* Benzopyrans / pharmacology Ceramides / metabolism Ceramides / pharmacology* Enzyme Activation Enzyme Inhibitors / pharmacology Golgi Apparatus / enzymology* Golgi Apparatus / metabolism Green Fluorescent Proteins HeLa Cells Humans Hydrogen Peroxide / pharmacology Luminescent Proteins / metabolism Microscopy, Fluorescence Mutation Phosphorylation Plasmids / metabolism Precipitin Tests Protein Kinase C / chemistry* Protein Kinase C / metabolism Protein Kinase C-delta Protein Structure, Tertiary Protein Transport RNA / chemistry RNA, Small Interfering / metabolism Rats Time Factors Tyrosine / chemistry Tyrosine / metabolism
IF 4.106
Times Cited 81
Human and Animal Cells HeLa