Division of Labor among Fission Dynamins Based on Substrate Size

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Membrane fission is crucial for endolysosomal vesicle formation and the division of organelles like mitochondria and peroxisomes.
• Dynamin superfamily proteins (DSPs) are key regulators of membrane fission, forming helical scaffolds that constrict and sever tubular membranes via GTP hydrolysis.

Purpose of the Study:

• To review and rationalize the mechanisms underlying the division of labor among DSPs.
• To explore the functional divergence of vesicle dynamins (VDs) and organelle dynamins (ODs) in membrane fission.

Main Methods:

• Review of existing literature on DSP structure, function, and substrate interactions.
• Comparative analysis of enzymatic properties and substrate size preferences of VDs and ODs.

Main Results:

• DSPs are categorized as VDs or ODs based on their cellular function.
• Despite conserved domains and similar enzymatic properties, VDs and ODs exhibit distinct preferences for tubular membrane substrate sizes.
• These size differences correlate with the distinct membrane structures involved in vesicle formation versus organelle division.

Conclusions:

• Evolutionary divergence in substrate size preference likely shaped the distinct roles of VDs and ODs.
• The structural basis for substrate size-dependent fission activity remains an open question for future research.