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SAMM50 is a receptor for basal piecemeal mitophagy and acts with SQSTM1/p62 in OXPHOS-induced mitophagy

Yakubu Princely Abudu1, Stephane Mouilleron2, Sharon A Tooze3

  • 1Autophagy Research Group, Department of Medical Biology, University of Tromsø, the Arctic University of Norway, Tromsø, Norway.

Autophagy
|July 19, 2021
PubMed

Insights

Basal mitophagy maintains cellular balance by clearing damaged mitochondria. Researchers found SAMM50 protein acts as a receptor, facilitating this process through interactions with specific protein complexes during metabolic shifts.

Area of Science:

  • Cell Biology
  • Mitochondrial Biology
  • Autophagy

Background:

  • Mitophagy is crucial for cellular homeostasis, involving the removal of damaged mitochondria.
  • While programmed and stress-induced mitophagy are well-studied, basal mitophagy mechanisms remain less understood.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying basal mitophagy.
  • To identify novel receptors involved in the piecemeal degradation of mitochondrial components.

Main Methods:

  • Identification of SAMM50 as a mitophagy receptor.
  • Analysis of SAMM50 interactions with Atg8-family proteins and SQSTM1/p62.
  • Investigation of SAMM50 function during metabolic switching to oxidative phosphorylation (OXPHOS).

Main Results:

  • SAMM50 was identified as a receptor for the piecemeal degradation of sorting and assembly (SAM) and mitochondrial contact site and cristae organizing system (MICOS) complexes.
  • SAMM50 directly interacts with Atg8-family proteins via a LIR motif and with SQSTM1/p62.
  • SAMM50 and SQSTM1 cooperate to mediate basal piecemeal mitophagy, particularly during a metabolic switch to OXPHOS.

Conclusions:

  • SAMM50 is a key receptor mediating basal mitophagy.
  • The SAMM50-SQSTM1 pathway is essential for efficient piecemeal degradation of mitochondrial components during metabolic adaptation.
Keywords:
Atg8MICOSOXPHOSSAMM50SQSTM1basalmetabolic switchp62piecemeal mitophagy

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