Tracking the Activity and Position of Mitochondrial β-Barrel Proteins

Methods Mol Biol. 2024:2778:221-236. doi: 10.1007/978-1-0716-3734-0_14.


Total interference reflection fluorescence (TIRF) microscopy of lipid bilayers is an effective technique for studying the lateral movement and ion channel activity of single integral membrane proteins. Here we describe how to integrate the mitochondrial outer membrane preprotein translocase TOM-CC and its β-barrel protein-conducting channel Tom40 into supported lipid bilayers to identify possible relationships between movement and channel activity. We propose that our approach can be readily applied to membrane protein channels where transient tethering to either membrane-proximal or intramembrane structures is accompanied by a change in channel permeation.

Keywords: Channels; Mitochondria; Protein translocation; Single molecule; TIRF microscopy; TOM; β-barrel membrane protein.

MeSH terms

  • Ion Channels / metabolism
  • Lipid Bilayers / metabolism
  • Mitochondria / metabolism
  • Mitochondrial Membrane Transport Proteins / metabolism
  • Mitochondrial Proteins* / metabolism
  • Saccharomyces cerevisiae Proteins* / metabolism


  • Mitochondrial Proteins
  • Mitochondrial Membrane Transport Proteins
  • Lipid Bilayers
  • Saccharomyces cerevisiae Proteins
  • Ion Channels