Mitochondrial function and actin regulate dynamin-related protein 1-dependent mitochondrial fission

Area of Science:

• Cell Biology
• Mitochondrial Biology
• Biochemistry

Background:

• Mitochondria exhibit diverse shapes (tubular, spherical, networks) crucial for cellular processes.
• Mitochondrial shape dynamics involve fusion and fission, regulated by proteins like DRP1.
• The link between mitochondrial function and shape regulation via fission/fusion remains unclear.

Purpose of the Study:

• To investigate how mitochondrial dysfunction influences mitochondrial shape.
• To elucidate the role of dynamin-related protein 1 (DRP1) and the actin cytoskeleton in mitochondrial shape changes.
• To determine the mechanisms by which altered mitochondrial function impacts mitochondrial morphology.

Main Methods:

• Inhibition of mitochondrial electron transport, ATP synthase, and the permeability transition pore (mtPTP).
• Assessment of mitochondrial shape changes using microscopy.
• Analysis of dynamin-related protein 1 (DRP1) recruitment and F-actin involvement.

Main Results:

• Electron transport inhibitors induced reversible mitochondrial fission dependent on DRP1 and F-actin.
• Disrupting F-actin reduced fission and DRP1 recruitment to mitochondria.
• Uncoupling of oxidative phosphorylation caused DRP1-independent swelling and a disk-like mitochondrial shape.

Conclusions:

• Mitochondrial dysfunction rapidly and reversibly alters mitochondrial shape through DRP1-dependent fission or swelling.
• The actin cytoskeleton plays a role in mitochondrial fission by facilitating DRP1 recruitment.
• A close relationship exists between mitochondrial fission, shape, and overall function.