p62/SQSTM1 Condensation Modulates Mitochondrial Clustering to Participate in Mitochondrial Quality Control

Area of Science:

• Cell Biology
• Neuroscience
• Molecular Biology

Background:

• Mitochondrial quality control is crucial for preventing aging-related neurodegenerative diseases like Parkinson's, Alzheimer's, ALS, and FTD.
• The protein p62 is implicated in mitophagy and "mitochondrial clustering" in ALS/FTD, but its precise role and disease relevance are unclear.

Purpose of the Study:

• To elucidate the molecular mechanism of p62 in mitochondrial clustering during mitophagy.
• To investigate the relationship between p62-mediated mitochondrial quality control and ALS/FTD pathogenesis.

Main Methods:

• Utilized cell biology techniques combined with optogenetics.
• Investigated the role of p62 phase separation (condensation) in mitochondrial clustering.

Main Results:

• p62 condensation drives the formation of "grape-like" mitochondrial clusters during PINK1/Parkin-mediated mitophagy.
• This clustering acts as an "arrest mechanism" or "brake" to reduce the turnover of dysfunctional mitochondria.
• ALS/FTD-related mutations in p62 disrupt condensation, inhibiting mitochondrial clustering and impairing quality control.

Conclusions:

• p62 condensation is a key regulator of organelle quality control through mitochondrial clustering.
• Dysfunctional p62 condensation contributes to the pathogenesis of ALS/FTD by compromising mitochondrial quality control mechanisms.