SARS-CoV-2 ORF3a blocks lysosomal cholesterol egress by disrupting VPS39-regulated NPC2 trafficking and BMP metabolism
Year: 2024
Type: preprint
Abstract: Cholesterol homeostasis relies on lysosomes, which release free cholesterol from degraded lipids. We show that SARS-CoV-2 blocks lysosomal cholesterol export through its protein ORF3a. ORF3a binds the HOPS subunit VPS39, and disrupting this interaction restores cholesterol trafficking. Two mechanisms underlie this defect. First, ORF3a-VPS39 interaction traps the sorting receptor CI-MPR and the retrieval complex retromer in endosomes/lysosomes, impairing trafficking of the cholesterol transporter NPC2. Retromer deletion reproduced these defects. Second, ORF3a reduces bis(monoacylglycerol)phosphates (BMPs), lysosomal lipids required for cholesterol export. Lipidomics and proteomics revealed altered metabolism of BMP precursors, mitochondrial phosphatidylglycerols (PGs), and reduced mitochondrial proteins at lysosomes. ORF3a-VPS39 interaction decreased lysosome-mitochondrion membrane contact sites (MCS), excluding autophagy or mitochondrion-derived vesicles as routes for PG transfer. VPS39 deletion decreased the MCS and BMPs. These findings identify VPS39 as a regulator of NPC2 trafficking and BMP biosynthesis and reveal that ORF3a disrupts both pathways to block cholesterol egress.
Authors: Baley A. Goodson, Valeria Montenegro Vazquez, Aliza Doyle, Oralia M. Kolaczkowski, Rui Liu, Jingyue Jia, Morié Ishida, Hu Wang, Xianlin Han, Chunyan Ye, Alison M. Kell, Steven B. Bradfute, Monica Rosas Lemus, Jing Pu
Language: English
Subfield: Cell Biology
Domain: Life Sciences
Open Access status: green
Awards: Lysosome‐Lipid Droplet Interactions in Fatty Acid Metabolism, San Antonio Nathan Shock Center of Excellence in the Biology of Aging, Initiative to Maximize Student Diversity at the University of New Mexico Health Sciences Center 2021, Cellular Mechanisms of Lysosomal Damage Response, Autophagy, Inflammation and Metabolism (AIM) in Disease Center - Phase 2.
OpenAlex ID: W4404366562