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Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes
15:43

Assessment of Mitochondrial Functions and Cell Viability in Renal Cells Overexpressing Protein Kinase C Isozymes

Published on: January 7, 2013

Activation of mutant protein kinase Cgamma leads to aberrant sequestration and impairment of its cellular function

Graeme Doran1, Kay E Davies, Kevin Talbot

  • 1MRC Functional Genetics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK.

Biochemical and Biophysical Research Communications
|May 28, 2008
PubMed

Insights

Mutations in protein kinase Cgamma (PKCgamma) cause spinocerebellar ataxia type 14 (SCA14). Aberrant PKCgamma aggregation in early endosomes may reduce activity, leading to Purkinje cell damage in SCA14 patients.

Area of Science:

  • Neuroscience
  • Cell Biology
  • Genetics

Background:

  • Spinocerebellar ataxia type 14 (SCA14) is a neurodegenerative disease linked to mutations in protein kinase Cgamma (PKCgamma).
  • Understanding the molecular mechanisms underlying PKCgamma dysfunction in SCA14 is crucial for developing therapeutic strategies.

Purpose of the Study:

  • To investigate the cellular consequences of SCA14-associated PKCgamma mutations.
  • To elucidate the mechanism by which PKCgamma mutations lead to Purkinje cell damage.

Main Methods:

  • Expression of various SCA14-associated PKCgamma mutations as fusion proteins in cultured cells.
  • Stimulation of cells using purinoceptors.
  • Immunocytochemistry using antibodies against phosphorylated PKCgamma and the early endosome marker EEA1.
  • Assessment of protein redistribution under oxidative stress conditions.

Main Results:

  • Expression of SCA14-associated PKCgamma mutations consistently induced cytoplasmic aggregate formation upon purinoceptor stimulation.
  • These aggregates co-localized with phosphorylated PKCgamma and the early endosome marker EEA1.
  • Mutant PKCgamma failed to redistribute to the cell membrane during oxidative stress, unlike wild-type protein.

Conclusions:

  • SCA14-associated PKCgamma mutations lead to aberrant sequestration of the protein within early endosomes.
  • This sequestration may impair PKCgamma function by reducing its availability and activity.
  • Reduced PKCgamma activity due to endosomal trapping is a proposed mechanism for Purkinje cell damage in SCA14.

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