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Updated: Jul 19, 2025

Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei
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Isolation of F1-ATPase from the Parasitic Protist Trypanosoma brucei

Published on: January 22, 2019

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A Msp1-containing complex removes orphaned proteins in the mitochondrial outer membrane of T. brucei

Markus Gerber1, Ida Suppanz2, Silke Oeljeklaus3

  • 1Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland.

Life Science Alliance
|August 16, 2023
PubMed

Insights

Trypanosomal Msp1 and VCP AAA-ATPases are key to mitochondrial quality control, degrading mislocalized outer membrane proteins. This pathway involves pATOM36 and Msp1-interacting proteins, suggesting conserved mechanisms across eukaryotes.

Area of Science:

  • Mitochondrial biology
  • Protein quality control
  • Cellular homeostasis

Background:

  • Mitochondrial outer membrane protein biogenesis is crucial for cellular function.
  • Misfolded or mislocalized proteins can disrupt mitochondrial homeostasis.
  • AAA-ATPases play vital roles in protein quality control pathways.

Purpose of the Study:

  • To investigate the role of trypanosomal Msp1 in mitochondrial protein quality control.
  • To identify Msp1-interacting proteins and their function in protein assembly.
  • To elucidate the pathway for degradation of unassembled mitochondrial outer membrane proteins.

Main Methods:

  • Pulldown assays to identify protein complexes.
  • RNA interference (RNAi) to deplete specific proteins.
  • Proteomic analyses to assess pathway components.
  • Inducible cell lines for precise genetic manipulation.

Main Results:

  • Trypanosomal Msp1 localizes to glycosomes and the mitochondrial outer membrane, forming a complex with four outer membrane proteins.
  • pATOM36 mediates the assembly of α-helical outer membrane proteins, including protein translocase subunits.
  • Inhibition of assembly triggers proteasomal digestion of unassembled substrates.
  • Msp1 and the AAA-ATPase VCP are involved in this quality control pathway.
  • Msp1-interacting proteins are required for efficient proteasomal digestion of pATOM36 substrates.

Conclusions:

  • Msp1 and VCP collaborate in a mitochondrial quality control pathway involving pATOM36.
  • This pathway ensures proper assembly of mitochondrial outer membrane proteins and degrades aberrant ones.
  • The findings suggest conserved mitochondrial quality control mechanisms in yeast and humans.

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