Related Experiment Video

Updated: May 24, 2026

Single-Molecule Imaging of Lateral Mobility and Ion Channel Activity in Lipid Bilayers using Total Internal Reflection Fluorescence (TIRF) Microscopy
08:55

Single-Molecule Imaging of Lateral Mobility and Ion Channel Activity in Lipid Bilayers using Total Internal Reflection Fluorescence (TIRF) Microscopy

Published on: February 17, 2023

Single molecule tracking fluorescence microscopy in mitochondria reveals highly dynamic but confined movement of

Anton Kuzmenko1, Stoyan Tankov, Brian P English

  • 1University of Tartu, Institute of Technology, Tartu, Estonia.

Scientific Reports
|February 23, 2012
PubMed

Insights

Individual Tom40 proteins in yeast mitochondria are highly mobile yet confined, indicating the entire Translocase of the Outer Membrane (TOM) complex is anchored. This research reveals insights into mitochondrial protein import dynamics.

Area of Science:

  • Mitochondrial biology
  • Protein transport
  • Cellular dynamics

Background:

  • Tom40 is a key protein in the mitochondrial outer membrane.
  • It forms the central channel of the Translocase of the Outer Membrane (TOM) complex.
  • The TOM complex facilitates protein import into mitochondria.

Purpose of the Study:

  • To characterize the diffusion properties of individual Tom40 molecules.
  • To understand the dynamics of the TOM complex within the mitochondrial outer membrane.
  • To investigate potential anchoring mechanisms of the TOM complex.

Main Methods:

  • Utilized yeast mitochondria and fused Tom40 with the photoconvertable fluorescent protein Dendra2.
  • Employed photoactivated localization microscopy (PALM) for high-resolution imaging.
  • Achieved millisecond temporal resolution to track molecular movement.

Main Results:

  • Individual Tom40 molecules exhibit highly dynamic movement within the mitochondrial outer membrane.
  • Despite high mobility, Tom40 diffusion is spatially confined.
  • These findings suggest that the TOM complex as a whole is anchored.

Conclusions:

  • The dynamic yet confined movement of Tom40 supports the hypothesis of a anchored TOM complex.
  • This anchoring may play a crucial role in regulating mitochondrial protein import.
  • Further research can explore the specific anchoring mechanisms and their functional implications.

More Related Videos

Multi-color Localization Microscopy of Single Membrane Proteins in Organelles of Live Mammalian Cells11:06

Multi-color Localization Microscopy of Single Membrane Proteins in Organelles of Live Mammalian Cells

Published on: June 30, 2018

Single-Molecule Tracking Microscopy - A Tool for Determining the Diffusive States of Cytosolic Molecules10:20

Single-Molecule Tracking Microscopy - A Tool for Determining the Diffusive States of Cytosolic Molecules

Published on: September 5, 2019

Related Concept Videos

Protein Dynamics in Living Cells01:19

Protein Dynamics in Living Cells

Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Translocation of Proteins into the Mitochondria01:19

Translocation of Proteins into the Mitochondria

Mitochondrial precursors are translocated to the internal subcompartments via independent mechanisms involving distinct protein machineries called translocases.
Sorting of outer membrane proteins:
Mitochondrial outer membrane proteins are of two types: the transmembrane, beta-barrel porins, and the membrane-anchored, alpha-helical proteins. Beta-barrel porin precursors are translocated by the TOM complex and inserted into the outer mitochondrial membrane by the SAM complex. In contrast,...
Energy to Drive Translocation01:37

Energy to Drive Translocation

Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...