Protein kinase C-epsilon promotes adipogenic commitment and is essential for terminal differentiation of 3T3-F442A preadipocytes.
The role of protein kinase C (PKC) isoforms in the commitment of multipotent fibroblasts to the adipocyte lineage and in their terminal differentiation into mature adipocytes was investigated. Ectopic overexpression of PKC-epsilon, but not other PKC isoforms, committed multipotent NIH-3T3 cells to adipogenic differentiation in the presence of hormonal inducers. In committed 3T3-F442A preadipocytes, PKC-epsilon protein expression increased during the course of terminal differentiation and cell-permeable PKC-epsilon inhibitory peptides, which prevent interaction with RACK (receptor for activated C-kinase) proteins, severely inhibited differentiation. PKC-epsilon accumulated in the nuclei of 3T3-F442A cells shortly after induction of differentiation and exhibited a distinctive punctate speckling immunocytochemical staining pattern. The spatiotemporal aspects of PKC-epsilon localization and expression coincided with that of C/EBP-beta, a transcription factor critically involved in promoting the early phase of adipogenesis. Collectively, these results demonstrate a role for PKC-epsilon in both adipogenic commitment and preadipocyte terminal differentiation.
Webb
P R
PR
Division of Cancer Studies, University of Manchester, School of Medicine, Oxford Road, Manchester M13 9PT, United Kingdom.
Doyle
C
C
Anderson
N G
NG
D016475:3T3 Cells; D017667:Adipocytes / Q000166:cytology*; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002467:Cell Nucleus / Q000201:enzymology / Q000648:ultrastructure; D007527:Isoenzymes / Q000378:metabolism; D051379:Mice; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D051744:Protein Kinase C-epsilon; D011994:Recombinant Proteins / Q000378:metabolism; D014162:Transfection
D007527:Isoenzymes; D011994:Recombinant Proteins; C497256:Prkce protein, mouse; D011493:Protein Kinase C; D051744:Protein Kinase C-epsilon