Calicivirus VP2 forms a portal-like assembly following receptor engagement

DOI: 10.1038/s41586-018-0852-1

Authors: Michaela J. Conley (Medical Research Council University of Glasgow Centre for Virus Research) , Marion Mcelwee (Medical Research Council University of Glasgow Centre for Virus Research) , Liyana Azmi (University of Glasgow) , Mads Gabrielsen (CRUK Beatson Institute) , Olwyn Byron (University of Glasgow) , Ian G. Goodfellow (University of Cambridge) , David Bhella (Medical Research Council University of Glasgow Centre for Virus Research)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Nature , VOL 565 , PAGES 377 - 381

State: Published (Approved)
Published: January 2019
Diamond Proposal Number(s): 11651

Abstract: To initiate infection, many viruses enter their host cells by triggering endocytosis following receptor engagement. However, the mechanisms by which non-enveloped viruses escape the endosome are poorly understood. Here we present near-atomic-resolution cryo-electron microscopy structures for feline calicivirus both undecorated and labelled with a soluble fragment of its cellular receptor, feline junctional adhesion molecule A. We show that VP2, a minor capsid protein encoded by all caliciviruses, forms a large portal-like assembly at a unique three-fold axis of symmetry, following receptor engagement. This assembly—which was not detected in undecorated virions—is formed of twelve copies of VP2, arranged with their hydrophobic N termini pointing away from the virion surface. Local rearrangement at the portal site leads to the opening of a pore in the capsid shell. We hypothesize that the portal-like assembly functions as a channel for the delivery of the calicivirus genome, through the endosomal membrane, into the cytoplasm of a host cell, thereby initiating infection. VP2 was previously known to be critical for the production of infectious virus; our findings provide insights into its structure and function that advance our understanding of the Caliciviridae.

Journal Keywords: Cryoelectron microscopy; SAXS; Virus–host interactions; Virus structures

Diamond Keywords: Viruses; Gastroenteritis

Subject Areas: Biology and Bio-materials


Instruments: B21-High Throughput SAXS

Added On: 17/01/2019 10:49

Discipline Tags:

Pathogens Infectious Diseases Health & Wellbeing Structural biology Life Sciences & Biotech

Technical Tags:

Scattering Small Angle X-ray Scattering (SAXS)