The interaction of alphavirus E1 protein with exogenous domain III defines stages in virus-membrane fusion

Gleyder Roman-Sosa, Margaret Kielian

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Alphaviruses such as Semliki Forest virus (SFV) are enveloped viruses that infect cells through a low-pH- triggered membrane fusion reaction mediated by the transmembrane fusion protein E1. E1 drives fusion by insertion of its hydrophobic fusion loop into the cell membrane and refolding to a stable trimeric hairpin. In this postfusion conformation, the immunoglobulin-like domain III (DIII) and the stem region pack against the central core of the trimer. Membrane fusion and infection can be specifically inhibited by exogenous DIII, which binds to an intermediate in the E1 refolding pathway. Here we characterized the properties of the E1 target for interaction with exogenous DIII. The earliest target for DIII binding was an extended membrane- inserted E1 trimer, which was not detectable by assays for the stable postfusion hairpin. DIII binding provided a tool to detect this extended trimer and to define a series of SFV fusion-block mutants. DIII binding studies showed that the mutants were blocked in distinct steps in fusion protein refolding. Our results suggested that formation of the initial extended trimer was reversible and that it was stabilized by the progressive fold-back of the DIII and stem regions.

Original languageEnglish (US)
Pages (from-to)12271-12279
Number of pages9
JournalJournal of Virology
Volume85
Issue number23
DOIs
StatePublished - Dec 2011

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Semliki Forest virus
Semliki forest virus
Alphavirus
Virus Internalization
Membrane Fusion
Protein Refolding
viruses
mutants
stems
immunoglobulins
cell membranes
Proteins
proteins
Cell Membrane
Viruses
Membranes
assays
Infection
infection
cells

ASJC Scopus subject areas

  • Immunology
  • Virology

Cite this

The interaction of alphavirus E1 protein with exogenous domain III defines stages in virus-membrane fusion. / Roman-Sosa, Gleyder; Kielian, Margaret.

In: Journal of Virology, Vol. 85, No. 23, 12.2011, p. 12271-12279.

Research output: Contribution to journalArticle

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