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The ATP-dependent PIM1 protease is required for the expression of intron-containing genes in mitochondria

L van Dyck1, W Neupert, T Langer

  • 1Institut für Physiologische Chemie der Universität München, 80336 München, Germany. Langer@bio.med.uni-muenchen.de

Genes & Development
|May 29, 1998
PubMed

Insights

The PIM1 protease is crucial for yeast mitochondrial DNA (mtDNA) integrity and gene expression. Lacking PIM1 protease impairs mtDNA stability, protein synthesis, and transcript processing, affecting cellular respiration.

Area of Science:

  • Mitochondrial biology
  • Molecular genetics
  • Protease function

Background:

  • The ATP-dependent PIM1 protease, a Lon-like protease in the mitochondrial matrix, is vital for yeast mitochondrial genome integrity.
  • Yeast cells deficient in PIM1 accumulate mitochondrial DNA (mtDNA) lesions, leading to loss of respiratory function.

Purpose of the Study:

  • To investigate novel functions of the PIM1 protease in mitochondrial biogenesis and gene expression.
  • To understand the role of PIM1 in stabilizing mtDNA and regulating the synthesis of mitochondrially encoded proteins.

Main Methods:

  • Utilized a multicopy suppressor to stabilize mtDNA in PIM1-deficient yeast mutants.
  • Analyzed the synthesis of cytochrome c oxidase subunit I (CoxI) and cytochrome b (Cob).
  • Examined mRNA splicing and transcript stability for COXI and COB genes.

Main Results:

  • Impaired synthesis of CoxI and Cob in pim1 mutants with mtDNA.
  • PIM1-mediated proteolysis is essential for mature COXI mRNA translation.
  • Deficiencies in COXI and COB transcript splicing and degradation of multi-intron transcripts were observed in pim1 mutants.

Conclusions:

  • PIM1 protease plays multiple essential roles in mitochondrial gene expression, including mtDNA maintenance, mRNA translation, and transcript processing.
  • These functions are critical for maintaining mitochondrial function and cellular respiration in yeast.

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