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KDELR2 Competes with Measles Virus Envelope Proteins for Cellular Chaperones Reducing Their Chaperone-Mediated Cell

Vishakha Tiwarekar1, Markus Fehrholz2, Jürgen Schneider-Schaulies3

  • 1Institute for Virology and Immunobiology, University of Würzburg, 97078 Würzburg, Germany. Vishu7yende@gmail.com.

Viruses
|January 10, 2019
PubMed

Insights

The endoplasmic reticulum protein KDELR2 inhibits measles virus replication by retaining essential chaperones, thus limiting viral protein transport. This finding reveals a novel host factor crucial for controlling measles virus spread.

Area of Science:

  • Virology
  • Cell Biology
  • Immunology

Background:

  • Measles virus (MV) replication is a significant public health concern.
  • The cytidine deaminase APOBEC3G (A3G) has been identified as an inhibitor of MV replication.
  • Host factors regulating viral replication are crucial for understanding antiviral mechanisms.

Purpose of the Study:

  • To identify host genes regulated by A3G that influence measles virus replication.
  • To elucidate the role of the endoplasmic reticulum (ER) protein KDELR2 in MV replication.
  • To understand the mechanism by which KDELR2 affects viral spread and titers.

Main Methods:

  • Microarray analysis to identify differentially regulated host genes upon A3G expression.
  • Over-expression and silencing of KDELR2 in cell culture models (Vero and CEM-SS T cells).
  • Measurement of MV titers and assessment of viral protein transport and chaperone interactions.

Main Results:

  • Ectopic expression of KDELR2 significantly reduced MV replication (~5 fold).
  • Silencing KDELR2 abrogated the antiviral activity of A3G, confirming KDELR2 as an A3G-regulated host factor.
  • KDELR2 retains ER chaperones (calnexin, GRP78/Bip), limiting their availability for measles virus envelope glycoproteins (H and F).

Conclusions:

  • KDELR2 acts as an antiviral host factor against measles virus.
  • The antiviral mechanism involves KDELR2 competing with MV proteins for essential ER chaperones.
  • This competition impairs the correct folding and cell surface transport of MV envelope glycoproteins, reducing virus spread.
Keywords:
GRP78KDELR2calnexinmeasles virussurface transport

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