Drosophila MIC10b can polymerize into cristae-shaping filaments

Area of Science:

• Mitochondrial biology
• Cellular ultrastructure
• Protein complexes

Background:

• Cristae, invaginations of the mitochondrial inner membrane, are vital for cellular energy metabolism.
• The MICOS (Mitochondrial Contact Site) complex is conserved and essential for cristae formation.
• MIC10 is a MICOS subunit supporting cristae through oligomerization.

Purpose of the Study:

• To identify the major MIC10 orthologue in *Drosophila melanogaster*.
• To investigate the function and mechanism of DmMIC10b in maintaining mitochondrial structure.
• To explore the role of DmMIC10b in fly physiology.

Main Methods:

• Identification and characterization of MIC10-like proteins in *Drosophila*.
• Analysis of DmMIC10b function through genetic manipulation (loss-of-function).
• Microscopy to assess mitochondrial ultrastructure and cristae architecture.

Main Results:

• CG41128/MINOS1b/DmMIC10b identified as the major MIC10 orthologue in flies.
• Loss of DmMIC10b destabilizes the MICOS complex, disrupts cristae, and reduces lifespan and fertility.
• DmMIC10b polymerizes into filaments that remodel mitochondrial membranes, dependent on specific residues.

Conclusions:

• DmMIC10b plays a critical role in regulating MICOS complex stability and mitochondrial ultrastructure in *Drosophila*.
• DmMIC10b's unique filament-forming ability is a novel mechanism for membrane remodeling.
• Findings offer insights into mitochondrial maintenance and potential therapeutic targets.