ROS induced distribution of mitochondria to filopodia by Myo19 depends on a class specific tryptophan in the motor...

Area of Science:

• Cell Biology
• Mitochondrial Dynamics
• Cytoskeletal Motors

Background:

• The actin cytoskeleton's role in mitochondrial function and dynamics is an emerging area of research.
• Myo19, an actin-based motor protein, localizes mitochondria to filopodia during glucose starvation.
• Mechanisms and dynamics of glucose starvation-induced mitochondrial translocation remain unclear.

Purpose of the Study:

• To elucidate the signaling pathways and dynamics involved in glucose starvation-induced mitochondrial localization to filopodia.
• To investigate the role of reactive oxygen species (ROS) in mediating this cellular response.
• To characterize the motor properties of Myo19 essential for mitochondrial transport.

Main Methods:

• Time-lapse fluorescence microscopy to observe Myo19 and mitochondria dynamics.
• Genetic manipulation (back-to-consensus mutation) of the Myo19 motor domain.
• Biochemical kinetic analysis of purified wild-type (WT) and mutant Myo19 motor domains.

Main Results:

• Reactive oxygen species (ROS) were found to mimic and mediate the glucose starvation-induced mitochondrial phenotype.
• ROS-induced Myo19 motility is dynamic, coupled with filopodia elongation and retraction.
• A specific mutation in the Myo19 motor domain significantly impaired its motility and duty ratio, hindering mitochondrial translocation.

Conclusions:

• Actin-based motility, specifically via Myo19, is critical for relocating mitochondria to filopodia in response to cellular cues like ROS.
• Myo19's unique motor properties, including its duty ratio, are essential for efficient mitochondrial propulsion.
• This study highlights the interplay between cytoskeletal dynamics, ROS signaling, and mitochondrial positioning.