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Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
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Mutation of the hydrophobic motif in a phosphorylation-deficient mutant renders protein kinase C delta more

Mrigendra B Karmacharya1, Jung-Ie Jang, Yoon-Jin Lee

  • 1Biomedical Research Center for Signal Transduction Networks, Department of Chemistry, Inha University, Incheon, Korea.

Archives of Biochemistry and Biophysics
|November 17, 2009
PubMed

Insights

Mutating Ser643 in Protein Kinase C delta (PKCdelta) to Ala (PKCdelta-S662A) enhances its apoptotic activity. This mutant shows increased tyrosine phosphorylation and faster membrane translocation, indicating a role in programmed cell death.

Area of Science:

  • Cellular Biology
  • Molecular Biology
  • Biochemistry

Background:

  • Protein Kinase C delta (PKCdelta) is a key regulator of cellular processes like survival and apoptosis.
  • PKCdelta activation, particularly through phosphorylation at Thr505, Ser643, and Ser662, is linked to apoptosis induction.
  • Tyrosine phosphorylation, especially at Tyr311, is also associated with PKCdelta activation and apoptosis.

Purpose of the Study:

  • To investigate the role of Ser662 phosphorylation in PKCdelta-mediated apoptosis.
  • To generate and characterize a hydrophobic motif phosphorylation-deficient mutant of PKCdelta (PKCdelta-S662A).

Main Methods:

  • Site-directed mutagenesis was used to create the PKCdelta-S662A mutant.
  • Apoptosis induction was studied in L929 murine fibroblasts.
  • Tyrosine phosphorylation and membrane translocation of wild-type and mutant PKCdelta were analyzed.

Main Results:

  • The PKCdelta-S662A mutant demonstrated enhanced apoptotic activity compared to wild-type PKCdelta.
  • The mutant PKCdelta-S662A exhibited increased tyrosine phosphorylation.
  • Faster translocation of the mutant PKCdelta-S662A to the cell membrane was observed.

Conclusions:

  • Phosphorylation at Ser662 is a critical regulatory site for PKCdelta activity in apoptosis.
  • The PKCdelta-S662A mutant is a valuable tool for studying the mechanisms of PKCdelta-induced apoptosis.
  • Targeting PKCdelta phosphorylation may offer therapeutic strategies for diseases involving apoptosis.

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