Commander complex regulates lysosomal function and is implicated in Parkinson's disease risk.

Area of Science:

• Neurogenetics
• Molecular Biology
• Cell Biology

Background:

• Genetic variants in the GBA1 gene, leading to reduced glucocerebrosidase (GCase) activity, are established risk factors for Parkinson's disease (PD) and dementia with Lewy bodies (DLB).
• Incomplete penetrance observed in individuals with GBA1 variants indicates the involvement of other genetic factors in the manifestation of PD and DLB.

Purpose of the Study:

• To identify novel genetic modifiers of GCase activity and lysosomal function.
• To investigate the role of COMMD3 protein in lysosomal homeostasis and its potential link to neurodegenerative diseases.

Main Methods:

• A pooled genome-wide CRISPR interference screen was employed to identify genes that modify GCase and lysosomal activity.
• The study involved analyzing the effects of COMMD3 loss on lysosomal protein release and endolysosomal delivery.

Main Results:

• The copper metabolism MURR1 domain-containing 3 (COMMD3) protein was identified as a modifier of GCase and lysosomal activity.
• Loss of COMMD3 function resulted in increased extracellular vesicle-mediated release of lysosomal proteins, impairing endolysosomal delivery and causing lysosomal dysfunction.
• Rare variants within the Commander gene family were found to be associated with an elevated risk of PD.

Conclusions:

• COMMD proteins and associated complexes play a crucial role in maintaining lysosomal homeostasis.
• These findings suggest that COMMD genes and their related complexes may act as modifiers in Parkinson's disease and other neurodegenerative disorders characterized by lysosomal dysfunction.