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Method for Measurement of Viral Fusion Kinetics at the Single Particle Level
14:59

Method for Measurement of Viral Fusion Kinetics at the Single Particle Level

Published on: September 7, 2009

Activation of fusion by the SER virus F protein: a low-pH-dependent paramyxovirus entry process

Shaguna Seth1, Annelet Vincent, R W Compans

  • 1Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

Journal of Virology
|May 14, 2003
PubMed

Insights

The SER virus fusion (F) protein

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • The SER virus, a paramyxovirus related to simian virus 5, does not typically form syncytia.
  • The SER virus F protein possesses a long cytoplasmic tail (CT), and its truncation or mutation enhances syncytium formation.
  • A long CT is hypothesized to stabilize the metastable conformation of the F protein.

Purpose of the Study:

  • To investigate the role of the SER virus F protein's cytoplasmic tail in syncytium formation.
  • To determine the conditions that trigger fusion activity of the SER virus F protein.

Main Methods:

  • Co-expression of wild-type SER virus F and hemagglutinin-neuraminidase (HN) proteins in cells.
  • Assessment of hemifusion, cytoplasmic content mixing, and syncytium formation at varying temperatures and pH levels.

Main Results:

  • Elevated temperatures enhanced hemifusion, content mixing, and syncytium formation of wild-type SER virus F and HN.
  • Reduced pH conditions (4.8–6.2) also enhanced hemifusion, content mixing, and syncytium formation.
  • Evidence suggests SER virus entry is a low-pH-dependent process, unlike other paramyxoviruses.

Conclusions:

  • The long cytoplasmic tail of the SER virus F protein likely stabilizes its metastable conformation.
  • Low pH triggers the conversion of the SER virus F protein to its fusion-active state.
  • SER virus entry into cells is mediated by a low-pH-dependent mechanism.

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