The Many Mechanisms of Viral Membrane Fusion Proteins

  • L. J. Earp
  • S. E. Delos
  • H. E. Park
  • J. M. White
Part of the Current Topics in Microbiology and Immunology book series (CT MICROBIOLOGY, volume 285)


Every enveloped virus fuses its membrane with a host cell membrane, thereby releasing its genome into the cytoplasm and initiating the viral replication cycle. In each case, one or a small set of viral surface transmembrane glycoproteins mediates fusion. Viral fusion proteins vary in their mode of activation and in structural class. These features combine to yield many different fusion mechanisms. Despite their differences, common principles for how fusion proteins function are emerging: In response to an activating trigger, the metastable fusion protein converts to an extended, in some cases rodlike structure, which inserts into the target membrane via its fusion peptide. A subsequent conformational change causes the fusion protein to fold back upon itself, thereby bringing its fusion peptide and its transmembrane domain—and their attached target and viral membranes—into intimate contact. Fusion ensues as the initial lipid stalk progresses through local hemifusion, and then opening and enlargement of a fusion pore. Here we review recent advances in our understanding of how fusion proteins are activated, how fusion proteins change conformation during fusion, and what is happening to the lipids during fusion. We also briefly discuss the therapeutic potential of fusion inhibitors in treating viral infections.


Membrane fusion protein Class I fusion protein Class II fusion protein Influenza HA HIV Env Low-pH activation Receptor activation Conformational changes Membrane dynamics Anti-fusion antivirals 


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • L. J. Earp
    • 1
  • S. E. Delos
    • 2
  • H. E. Park
    • 1
  • J. M. White
    • 2
  1. 1.Department of MicrobiologyUniversity of VirginiaCharlottesvilleUSA
  2. 2.Department of Cell Biology, School of MedicineUVA Health SystemCharlottesvilleUSA

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