Cholesterol is important for a post-adsorption step in the entry process of transmissible gastroenteritis virus

Cholesterol is a major constituent of detergent-resistant membrane microdomains (DRMs). We localized transmissible gastroenteritis virus (TGEV) spike (S) protein in DRMs in the viral envelope. Though S protein was not solubilized by cold non-ionic detergents, this behavior was unchanged when cholesterol was depleted from viral membrane by methyl-β-cyclodextrin (MβCD) and the protein did not comigrate with cellular DRM marker proteins in flotation analyses. Therefore, the S protein is not anchored in the viral membrane DRMs as they are known to occur in the plasma membrane. Cholesterol depletion from viral membrane may not affect the adsorption process as neither the sialic acid binding activity nor the binding to aminopeptidase N was reduced post-MβCD treatment. Reduced infectivity of cholesterol-depleted TGEV was observed only when the adsorption process occurred at 37 °C but not when the virus was applied at 4 °C. Cholesterol is important for a post-adsorption step, allowing membrane rearrangements that facilitate virus entry. © 2010 Elsevier B.V.
National Natural Science Foundation of China (30700591) to J.Y. National Natural Science Foundation of China (30700590; 30972195), Funding supported by Program for New Century Excellent Talents in Heilongjiang Provincial University (1155--NCET--005) and a visiting scholarship from Deutscher Akademischer Austauschdienst (DAAD) to X.R. are acknowledged. G.H. was supported by Deutsche Forschungsgemeinschaft (SFB621) and by the German Ministry of Education and Research (BMBF: FKZ 01KI0702)