Posttranslational oligomerization and cooperative acid activation of mixed influenza hemagglutinin trimers.
The influenza virus hemagglutinin (HA) is a well-characterized integral membrane glycoprotein composed of three identical subunits. We have analyzed the formation of mixed trimers in cells expressing two different HA gene products. The results show efficient and essentially random assembly of functional hybrid trimers provided that the HAs are from the same HA subtype. Trimerization is thus a posttranslational event, and subunits are recruited randomly from a common pool of monomers in the endoplasmic reticulum. Mixed trimers were not observed between HAs derived from different subtypes, indicating that the trimerization event is sequence specific. Mixed trimers containing mutant subunits were, moreover, used to establish that the acid-induced conformational change involved in the membrane fusion activity of HA is a highly cooperative event.
Boulay
F
F
Department of Cell Biology, Yale University School of Medicine, New Haven, Connecticut 06510.
Doms
R W
RW
Webster
R G
RG
Helenius
A
A
D000818:Animals; D002459:Cell Fusion / Q000187:drug effects; D002460:Cell Line; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral / Q000235:genetics / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D007118:Immunoassay; D009980:Influenza A virus / Q000235:genetics / Q000378:metabolism*; D046911:Macromolecular Substances; D011487:Protein Conformation; D011499:Protein Processing, Post-Translational
D019267:Hemagglutinin Glycoproteins, Influenza Virus; D006389:Hemagglutinins, Viral; D046911:Macromolecular Substances