Biophysical Society Conference | Estes Park 2023

Membrane Budding and Fusion

Tuesday Speaker Abstracts

MACROPINOCYTOSIS IN SARS-COV-2 INFECTION

Xin Wang 1 ; Sue Han 1 ; Tiansheng Li 2 ; Alberto Lopezmunoz 2 ; Ivan Kosik 2 ; Jonathan Yewdell 2 ; Ling-Gang Wu 1 ; 1 National Institute of Neurological Disorders and Stroke, Bethesda, MD, USA 2 National Institute of Allergy and Infectious Diseases, Bethesda, MD, USA SARS-CoV-2 is a main target for combat against the global pandemic COVID-19. Accumulated studies that adopt spike protein or detect viral genome expression but not virion itself establish the current view that the endocytosis of SARS-CoV-2 is mediated by clathrin-mediated endocytosis. By labeling endocytic vesicles and tracking fluorescent labelled pseudo-SARS CoV-2 virion, we observed that the virus is internalized into endosome-like vesicles with size of ~300 nm, each taking up 1-5 viral particles. By Taking advantage of super-resolution stimulated emission depletion (STED) microscopy, we clearly show that the attached virus is internalized via membrane ruffle-mediated macropinocytosis, but not classic clathrin-coated vesicles with a diameter of 80-120 nm. The internalization of multiple virions via membrane ruffle-mediated structure into large vacuole but not classic clathrin-coated vesicles was also confirmed with Electron microscope (EM). In addition, in combination with pharmaceutical treatment and monitoring viral genome expression, we demonstrate that the interference of macropinocytosis components could lead to remarkably reduction in virus endocytosis and viral infection. Further, we show that membrane ruffle-mediated macropinocytosis could be involved in the cell entry of authentic SARS-CoV-2. Taking together, our results revealed that macropinocytosis could be a major pathway for viral endocytosis which also leads to subsequent viral infection.

30