Activation of a paramyxovirus fusion protein is modulated by inside-out signaling from the cytoplasmic tail

David L. Waning, Charles J. Russell, Theodore S. Jardetzky, Robert A. Lamb

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Many viruses have evolved fusion-mediating glycoproteins that couple the energy released from irreversible protein refolding to the work of membrane fusion. The viral fusion proteins require a triggering event to undergo a cascade of tightly regulated conformational changes. Different isolates of the paramyxovirus SV5 fusion (F) protein have either a short (20-residue) or long (42-residue) cytoplasmic tail (CT), and a long CT suppresses fusion activity in a sequence-specific manner. Addition of a domain to the F protein CT, which has the propensity to forma three-helix bundle, stabilizes the F protein and increases the energy required for fusion activation. Quantitative cell-cell fusion assays and measurement of ectodomain conformation by monoclonal antibody reactivity indicate that this suppression of fusion by the long CT or addition of a three-helix bundle occurs at a step preceding initial membrane merger. The data suggest that F protein activation involves CT signaling to the ectodomain.

Original languageEnglish (US)
Pages (from-to)9217-9222
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number25
Publication statusPublished - Jun 22 2004


All Science Journal Classification (ASJC) codes

  • General

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