Receptor-mediated Drp1 oligomerization on endoplasmic reticulum.

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Dynamin-related protein 1 (Drp1) is essential for mitochondrial and peroxisomal division.
• Endoplasmic reticulum (ER) and actin filaments are known to positively influence mitochondrial division, but their mechanisms are unclear.
• Drp1 recruitment and oligomerization are regulated by mitochondrial receptors like Mff, MiD49, MiD51, and Fis1.

Purpose of the Study:

• To investigate the role of the endoplasmic reticulum (ER) in Drp1 oligomerization and mitochondrial division.
• To elucidate the mechanisms by which ER influences Drp1-mediated organelle division.

Main Methods:

• Immunofluorescence microscopy to visualize Drp1, Mff, and Fis1 localization on ER, mitochondria, and peroxisomes.
• Cellular assays to assess Drp1 oligomerization and mitochondrial division.
• Genetic manipulation, including suppression of Mff and inhibition of actin polymerization via INF2.

Main Results:

• A distinct population of Drp1 oligomers was found associated with the ER in mammalian cells.
• Subpopulations of Mff and Fis1 were also localized to the ER.
• Suppression of Mff or inhibition of actin polymerization reduced all Drp1 oligomer populations and mitochondrial division.
• Targeting Mff to the ER stimulated mitochondrial division.

Conclusions:

• The ER serves as a platform for Drp1 oligomerization.
• ER-associated Drp1 contributes significantly to mitochondrial division.
• Mff and actin filaments, potentially via INF2, play critical roles in regulating Drp1 assembly and function on the ER for organelle division.