VPS13A is closely associated with mitochondria and is required for efficient lysosomal degradation

Area of Science:

• Cell Biology
• Neuroscience
• Human Genetics

Background:

• VPS13A protein dysfunction causes chorea-acanthocytosis (ChAc), a neurodegenerative disorder.
• Defective autophagy flux is observed in ChAc, but the underlying mechanisms remain unclear.
• VPS13A family members are implicated in various human diseases.

Purpose of the Study:

• Investigate the function of VPS13A in endosome trafficking and lysosomal degradation.
• Elucidate the mechanistic link between VPS13A deficiency and impaired autophagy.
• Explore the potential role of VPS13A in inter-organelle communication, particularly with mitochondria.

Main Methods:

• Identified VPS13A and RAB7A interaction in Dictyostelium discoideum and conserved in human HeLa cells.
• Assessed VPS13A's role in endocytic trafficking and lysosomal degradation.
• Examined VPS13A localization at mitochondria-associated membrane contact sites (MCS) with endosomes and endoplasmic reticulum.

Main Results:

• VPS13A interacts with RAB7A, a key regulator of endosome trafficking.
• VPS13A deficiency leads to general defects in endocytic trafficking and lysosomal degradation, contributing to reduced autophagy.
• VPS13A localizes to mitochondria-endosome and mitochondria-ER interfaces, and its absence alters MCS.
• Altered membrane contact sites suggest VPS13A's role in inter-organelle communication.

Conclusions:

• VPS13A deficiency causes broader endolysosomal trafficking defects, not just autophagy impairment.
• VPS13A's function at mitochondria-associated membrane contact sites is crucial for cellular homeostasis.
• Targeting the endolysosomal pathway and inter-organelle communication presents a potential therapeutic strategy for ChAc.