Monoclonal antibodies localize events in the folding, assembly, and intracellular transport of the influenza virus hemagglutinin glycoprotein.
We used monoclonal antibodies that recognize monomeric and/or trimeric forms of the influenza virus hemagglutinin (HA) to study biosynthesis of this integral membrane protein in influenza virus-infected cells. We find the following: First, the globular head of the HA folds into its mature conformation in the endoplasmic reticulum prior to the assembly of HA monomers into trimers. Second, trimerization begins within 1 to 2 min following synthesis, with a half-time of approximately 5 min. Third, trimerization occurs only after the HA has been transported from the endoplasmic reticulum. Fourth, newly formed trimers are sensitive to acid-induced conformational alterations associated with viral fusion activity.
D000818:Animals; D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D001692:Biological Transport; D002460:Cell Line; D004721:Endoplasmic Reticulum / Q000276:immunology; D000939:Epitopes / Q000032:analysis; D005455:Fluorescent Antibody Technique; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000235:genetics* / Q000276:immunology; D046911:Macromolecular Substances; D009975:Orthomyxoviridae / Q000276:immunology; D011487:Protein Conformation
D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D000939:Epitopes; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D046911:Macromolecular Substances