Protocol for assessing the clogging of the mitochondrial translocase of the outer membrane by precursor proteins in human cells

STAR Protoc. 2025 Mar 21;6(1):103617. doi: 10.1016/j.xpro.2025.103617. Epub 2025 Jan 31.

Abstract

Protein import into the mitochondria is required for organellar function. Inefficient import can result in the stalling of mitochondrial precursors inside the translocase of the outer membrane (TOM) and blockage of the mitochondrial entry gate. Here, we present a protocol to assess the clogging of TOM by mitochondrial precursors in human cell lines. We describe how the localization of mitochondrial precursors can be determined by cellular fractionation. We then show how co-immunoprecipitation can be used to test the stalling of precursors inside TOM. For complete details on the use and execution of this protocol, please refer to Kim et al.1.

Keywords: cell biology; cell culture; cell separation/fractionation; molecular biology; protein biochemistry; protein expression and purification.

MeSH terms

  • Cell Fractionation / methods
  • Humans
  • Immunoprecipitation / methods
  • Mitochondria* / metabolism
  • Mitochondrial Membranes* / metabolism
  • Mitochondrial Precursor Protein Import Complex Proteins
  • Protein Precursors* / metabolism
  • Protein Transport

Substances

  • Protein Precursors
  • Mitochondrial Precursor Protein Import Complex Proteins