Retroviral entry mediated by receptor priming and low pH triggering of an envelope glycoprotein

Cell. 2000 Nov 10;103(4):679-89. doi: 10.1016/s0092-8674(00)00170-7.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Avian Leukosis Virus / growth & development*
  • Gene Products, env / metabolism*
  • Giant Cells
  • Glycoproteins / metabolism*
  • Hydrogen-Ion Concentration*
  • Membrane Fusion
  • Protein Conformation
  • Receptors, Virus / metabolism*
  • Virus Replication


  • Gene Products, env
  • Glycoproteins
  • Receptors, Virus