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Conformational aberrance of the sendai virus F0 protein in thapsigargin-treated cells allowing exit from the

A Ono1, M Kawakita

  • 1Department of Physiological Chemistry, Tokyo Metropolitan Institute of Medical Science, Rinshoken.

Journal of Biochemistry
|December 1, 1995
PubMed

Insights

Calcium depletion inhibits Sendai virus F0 protein transport by causing conformational abnormalities. Misfolded F0 protein is arrested in the Golgi complex and rapidly degraded, impacting viral entry.

Area of Science:

  • Virology
  • Cell Biology
  • Protein Trafficking

Background:

  • The Sendai virus F0 protein is essential for viral entry.
  • Intracellular transport of viral proteins is crucial for infection.
  • Calcium ions play a role in cellular processes, including protein transport.

Purpose of the Study:

  • To investigate the effect of calcium depletion on Sendai virus F0 protein transport.
  • To identify the specific stage and mechanism of F0 protein transport inhibition.
  • To understand the conformational changes and degradation pathways of inhibited F0 protein.

Main Methods:

  • Using thapsigargin and ionomycin to deplete intracellular calcium stores.
  • Employing pulse-chase labeling and SDS-polyacrylamide gel electrophoresis to analyze F0 protein.
  • Utilizing endoglycosidase H digestion and monoclonal antibody recognition to assess protein conformation and modifications.

Main Results:

  • Thapsigargin and ionomycin inhibited F0 protein transport, dependent on intracellular calcium levels.
  • F0 protein transport was arrested between the trans-Golgi complex and the plasma membrane.
  • Conformational abnormalities in F0 protein were observed, affecting its recognition by antibodies but not its exit from the endoplasmic reticulum.
  • Arrested F0 protein was rapidly degraded, suggesting a role for Golgi quality control mechanisms.

Conclusions:

  • Intracellular calcium depletion is critical for inhibiting Sendai virus F0 protein transport.
  • Misfolded F0 protein encounters a quality control system in the Golgi complex, leading to its degradation.
  • These findings provide insights into the mechanisms of viral protein trafficking and cellular quality control.

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