Human Neonatal Fc Receptor Is the Cellular Uncoating Receptor for Enterovirus B

Xin Zhao1, Guigen Zhang2, Sheng Liu3

  • 1CAS Key Laboratory of Pathogenic Microbiology and Immunology, Institute of Microbiology, Chinese Academy of Sciences, 100101 Beijing, China; CAS Center for Influenza Research and Early-Warning (CASCIRE), Chinese Academy of Sciences, 100101 Beijing, China.

Cell
|May 21, 2019
PubMed

Insights

Human neonatal Fc receptor (FcRn) acts as the uncoating receptor for Enterovirus B (EV-B), facilitating virus entry. This discovery reveals the mechanism behind EV-B uncoating, crucial for understanding these severe human infectious diseases.

Area of Science:

  • Virology
  • Structural Biology
  • Immunology

Background:

  • Enterovirus B (EV-B) causes severe human diseases, but its entry and uncoating mechanisms are not fully understood.
  • While receptors for some EV-B like coxsackievirus B are known, echovirus and other EV-B entry pathways remain unclear.
  • Identifying viral uncoating receptors is critical for understanding picornavirus pathogenesis.

Purpose of the Study:

  • To identify the cellular receptor responsible for the uncoating process of Enterovirus B (EV-B).
  • To elucidate the structural mechanisms underlying EV-B attachment and uncoating.
  • To provide a structural basis for understanding EV-B entry into host cells.

Main Methods:

  • Utilized cryo-electron microscopy (cryo-EM) to obtain atomic and near-atomic resolution structures.
  • Investigated the interaction between EV-B and the human neonatal Fc receptor (FcRn).
  • Analyzed structural changes in viral particles during entry under acidic conditions.

Main Results:

  • Identified human neonatal Fc receptor (FcRn) as the uncoating receptor for major EV-B serotypes.
  • Demonstrated that FcRn binds to the viral "canyon" via its FCGRT subunit.
  • Observed that FcRn binding induces "pocket factor" release and conformational changes in the virion under acidic conditions, distinct from CD55-mediated attachment.

Conclusions:

  • FcRn plays a key role in EV-B uncoating, a critical step in viral entry.
  • Structural insights reveal how FcRn binding initiates conformational changes necessary for virus release.
  • This finding provides a novel structural framework for understanding enterovirus entry and developing therapeutic strategies.

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