Biochemical consequences of a mutation that controls the cholesterol dependence of Semliki Forest virus fusion

Prodyot K. Chatterjee, Malini Vashishtha, Margaret Kielian

Research output: Contribution to journalArticle

45 Citations (Scopus)

Abstract

The enveloped alphavirus Semliki Forest virus (SFV) infects cells via a low-pH-triggered membrane fusion reaction that requires cholesterol and sphingolipid in the target membrane. Cholesterol-depleted insect cells are highly resistant to alphavirus infection and were used to select srf-3, an SFV mutant that is ~100-fold less cholesterol dependent for infection due to a single amino acid change in the E1 spike subunit, proline 226 to serine. Sensitive lipid-mixing assays here demonstrated that the in vitro fusion of srf-3 and wild-type (wt) virus with cholesterol-containing liposomes had comparable kinetics, activation energies, and sphingolipid dependence. In contrast, srf-3 fusion with sterol-free liposomes was significantly more efficient than that of wt virus. Thus, the srf-3 mutation does not affect its general fusion properties with purified lipid bilayers but causes a marked and specific reduction in cholesterol dependence. Upon exposure to low pH, the E1 spike subunit undergoes distinct conformational changes, resulting in the exposure of an acid conformation-specific epitope and formation of an E1 homotrimer. These conformational changes were strongly cholesterol and sphingolipid dependent for wt SFV and strikingly less cholesterol dependent for srf-3. Our results thus demonstrate the functional importance of fusogenic E1 conformational changes in the control of SFV cholesterol dependence.

Original languageEnglish (US)
Pages (from-to)1623-1631
Number of pages9
JournalJournal of Virology
Volume74
Issue number4
DOIs
StatePublished - 2000

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Semliki Forest virus
Semliki forest virus
Cholesterol
cholesterol
mutation
Mutation
sphingolipids
Sphingolipids
Alphavirus
Liposomes
Alphavirus Infections
Viruses
viruses
lipid bilayers
Membrane Fusion
Lipid Bilayers
Sterols
activation energy
Proline
infection

ASJC Scopus subject areas

  • Immunology

Cite this

Biochemical consequences of a mutation that controls the cholesterol dependence of Semliki Forest virus fusion. / Chatterjee, Prodyot K.; Vashishtha, Malini; Kielian, Margaret.

In: Journal of Virology, Vol. 74, No. 4, 2000, p. 1623-1631.

Research output: Contribution to journalArticle

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