Pptc7 maintains mitochondrial protein content by suppressing receptor-mediated mitophagy.

Area of Science:

• Mitochondrial Biology
• Cellular Metabolism
• Molecular Genetics

Background:

• Pptc7 is a mitochondrial phosphatase crucial for maintaining mitochondrial homeostasis.
• Loss of Pptc7 in newborns leads to severe metabolic dysfunction and lethality.
• The role of Pptc7 in adult mitochondrial maintenance and mitophagy remains largely unexplored.

Approach:

• Utilized an inducible knockout mouse model to study Pptc7 deletion in adult mice.
• Employed phosphoproteomics to identify altered phosphorylation sites upon Pptc7 loss.
• Investigated the impact of Pptc7 deficiency on mitophagy pathways and receptor expression in vivo and in vitro.

Key Points:

• Adult Pptc7 knockout mice show reduced mitochondrial mass and increased mitophagy.
• Mitophagy receptors Bnip3 and Nix are upregulated in Pptc7-deficient models.
• Phosphoproteomics revealed elevated phosphosites on Bnip3 and Nix, suggesting Pptc7's regulatory role.
• Pptc7 deletion disrupts metabolic pathways, contributing to mitochondrial dysfunction.

Conclusions:

• Pptc7 plays a critical role in regulating mitophagy and maintaining mitochondrial content in adult organisms.
• Dysregulation of mitochondrial protein phosphorylation by Pptc7 impacts metabolic pathways and organelle function.
• Pptc7 may directly influence the function or stability of mitophagy receptors like Bnip3 and Nix.