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HCMV-encoded glycoprotein M (UL100) interacts with Rab11 effector protein FIP4

Magdalena A Krzyzaniak1, Michael Mach, William J Britt

  • 1Department of Microbiology, University of Alabama at Birmingham, CHB160, Birmingham, AL 35233, USA.

Traffic (Copenhagen, Denmark)
|September 19, 2009
PubMed

Insights

Human cytomegalovirus (HCMV) glycoprotein M (gM) interacts with FIP4, a protein crucial for viral assembly. This interaction impacts infectious virus production by influencing the endosomal recycling compartment, independent of Arf5/Arf6.

Area of Science:

  • Virology
  • Cell Biology
  • Molecular Biology

Background:

  • Human cytomegalovirus (HCMV) is an enveloped virus with a complex glycoprotein envelope.
  • Glycoprotein M (gM, UL100) is the most abundant HCMV envelope glycoprotein, forming a complex with glycoprotein N (gN, UL73).
  • Viral assembly and egress are critical stages in the HCMV life cycle, involving intricate cellular machinery.

Purpose of the Study:

  • To investigate the interaction between HCMV gM and cellular proteins involved in vesicular transport.
  • To elucidate the role of FIP4 and Rab11 in HCMV assembly and infectious virus production.

Main Methods:

  • Yeast two-hybrid screening to identify interacting partners of gM.
  • Depletion of FIP4 expression in HCMV-infected cells using RNA interference.
  • Expression of dominant-negative Rab11(S25N) in HCMV-infected cells.
  • Analysis of viral production and assembly compartment (AC) phenotype.

Main Results:

  • The gM carboxy-terminal cytoplasmic tail (gM-CT) was found to interact with FIP4, a Rab11-GTPase effector.
  • Depletion of FIP4 or expression of dominant-negative Rab11(S25N) reduced infectious HCMV production and altered the AC phenotype.
  • FIP4 interaction with gM-CT did not impede Rab11 recruitment but limited FIP4 binding to Arf5/Arf6.

Conclusions:

  • The endosomal recycling compartment (ERC) contributes to HCMV cytoplasmic envelopment.
  • HCMV utilizes FIP4 in a novel manner, potentially independent of its canonical Arf5/Arf6-mediated functions, for efficient viral assembly and egress.

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