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Crystal structure of CD155 and electron microscopic studies of its complexes with polioviruses

Ping Zhang1, Steffen Mueller, Marc C Morais

  • 1Department of Biological Sciences, Purdue University, 915 West State Street, West Lafayette, IN 47907-2054, USA.

Proceedings of the National Academy of Sciences of the United States of America
|November 18, 2008
PubMed

Insights

Poliovirus entry involves its receptor CD155 binding, causing structural changes. This process, detailed by structural analysis, reveals how the virus releases its genome into host cells.

Area of Science:

  • Virology
  • Structural Biology
  • Biochemistry

Background:

  • Poliovirus (PV) initiates infection by binding to its receptor, CD155.
  • This interaction triggers a conformational change in the virus, transitioning from a 160S to a 135S particle.
  • CD155 is a transmembrane protein with three extracellular immunoglobulin-like domains (D1-D3), with D1 being the primary binding site for PV.

Purpose of the Study:

  • To elucidate the structural mechanisms of poliovirus-receptor interaction and subsequent viral entry.
  • To analyze the structural basis for poliovirus recognition of CD155 at near-atomic resolution.
  • To compare poliovirus-receptor interactions with those of other picornaviruses like human rhinoviruses.

Main Methods:

  • X-ray crystallography was used to determine the structure of the CD155 D1D2 domains.
  • Cryoelectron microscopy (cryo-EM) reconstructions of virus-receptor complexes were generated at approximately 8.5-Å resolution for all three PV serotypes.
  • Structural data were integrated with existing mutational data to model the entry process.

Main Results:

  • High-resolution structures revealed that poliovirus-receptor interactions rely heavily on hydrophobic interactions, potentially adapting to varying pH environments.
  • The pocket factor remains bound during initial virus-receptor recognition.
  • Upon subsequent entry at physiological temperatures, CD155 moves deeper into the viral canyon, expelling the pocket factor and dissociating viral subunits to form the 135S particle.

Conclusions:

  • The study provides a detailed structural understanding of the poliovirus entry mechanism.
  • The findings highlight the dynamic structural rearrangements of the virus and receptor during host cell entry.
  • This work offers insights into the broader mechanisms of non-enveloped virus cell entry.

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