Abstract
Prolonged activation of protein kinase C (PKC) types α and β by tumor-promoting phorbol esters leads to desensitization of the phorbol ester response, downregulation of protein kinase C activity and depletion of the protein kinase C polypeptide. When the γ isoenzyme of PKC is transiently expressed in COS-1 cells and exposed to phorbol esters, PKC-γ is downregulated in COS cells although these cells do not normally express this subtype. A point mutation in the purative ATP-binding site (Lys-380→Met-380) of the protein kinase C γ isoenzyme which results in a kinase-deficient enzyme does not interfere with this downregulation. Our results suggest that autophosphorylation or constitutive signalling through the protein kinase C-γ kinase domain is not a prerequisite for downregulation of PKC activity.
Original language | English |
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Pages (from-to) | 262-266 |
Number of pages | 5 |
Journal | FEBS Letters |
Volume | 280 |
Issue number | 2 |
DOIs | |
Publication status | Published - Mar 25 1991 |
Keywords
- Baculovirus expression
- Downregulation
- Kinase-deficient mutant
- Phorbol ester
- Protein kinase C
ASJC Scopus subject areas
- Biophysics
- Structural Biology
- Biochemistry
- Molecular Biology
- Genetics
- Cell Biology