Retroviral entry mediated by receptor priming and low pH triggering of an envelope glycoprotein.
Avian leukosis virus (ALV) has been used as a model system to understand the mechanism of pH-independent viral entry involving receptor-induced conformational changes in the viral envelope (Env) glycoprotein that lead to membrane fusion. Here, we report the unexpected finding that ALV entry depends on a critical low pH step that was overlooked when this virus was directly compared to the classical pH-dependent influenza A virus. In contrast to influenza A virus, receptor interaction plays an essential role in priming ALV Env for subsequent low pH triggering. Our results reveal a novel principle in viral entry, namely that receptor interaction can convert a pH-insensitive viral glycoprotein to a form that is responsive to low pH.
Mothes
W
W
Department of Microbiology and Molecular Genetics, Harvard Medical School, Boston, MA 02115, USA.
Boerger
A L
AL
Narayan
S
S
Cunningham
J M
JM
Young
J A
JA
D001354:Avian Leukosis Virus / Q000254:growth & development*; D015686:Gene Products, env / Q000378:metabolism*; D015726:Giant Cells; D006023:Glycoproteins / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008561:Membrane Fusion; D011487:Protein Conformation; D011991:Receptors, Virus / Q000378:metabolism*; D014779:Virus Replication
D015686:Gene Products, env; D006023:Glycoproteins; D011991:Receptors, Virus