Abstract 4356: Identification of the anthrax toxin receptor (ANTXR1) as the high affinity cellular receptor for Seneca Valley Virus (SVV)

Seneca Valley virus (SVV) is an oncolytic picornavirus with selective tropism for neuroendocrine cancers. SVV mediates cell entry by attachment to the receptor anthrax toxin receptor 1 (ANTXR1). Here we determine atomic structures of mature SVV particles alone and in complex with ANTXR1 in both neutral and acidic conditions, as well as empty “spent” particles in complex with ANTXR1 in acidic conditions by cryoelectron microscopy. SVV engages ANTXR1 mainly by the VP2 DF and VP1 CD loops, leading to structural changes in the VP1 GH loop and VP3 GH loop, which attenuate interprotomer interactions and destabilize the capsid assembly. Despite lying on the edge of the attachment site, VP2 D146 interacts with the metal ion in ANTXR1 and is required for cell entry. Though the individual substitution of most interacting residues abolishes receptor binding and virus propagation, a serine-to-alanine mutation at VP2 S177 significantly increases SVV proliferation. Acidification of the SVV–ANTXR1 complex results in a major reconfiguration of the pentameric capsid assemblies, which rotate ∼20° around the icosahedral fivefold axes to form a previously uncharacterized spent particle resembling a potential uncoating intermediate with remarkable perforations at both two- and threefold axes. These structures provide high-resolution snapshots of SVV entry, highlighting opportunities for anticancer therapeutic optimization.

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Structural basis for anthrax toxin receptor 1 recognition by Seneca Valley Virus

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1810664115 ◽

2018 ◽

Vol 115 (46) ◽

pp. E10934-E10940 ◽

Cited By ~ 3

Author(s):

Nadishka Jayawardena ◽

Laura N. Burga ◽

Richard A. Easingwood ◽

Yoshimasa Takizawa ◽

Matthias Wolf ◽

...

Keyword(s):

Conformational Changes ◽

Protective Antigen ◽

Therapeutic Option ◽

Oncolytic Viruses ◽

Anthrax Toxin ◽

Bacterial Toxin ◽

Structural Basis ◽

Electron Microscopy Analysis ◽

Toxin Receptor ◽

Seneca Valley Virus

Recently, the use of oncolytic viruses in cancer therapy has become a realistic therapeutic option. Seneca Valley Virus (SVV) is a newly discovered picornavirus, which has earned a significant reputation as a potent oncolytic agent. Anthrax toxin receptor 1 (ANTXR1), one of the cellular receptors for the protective antigen secreted by Bacillus anthracis, has been identified as the high-affinity cellular receptor for SVV. Here, we report the structure of the SVV-ANTXR1 complex determined by single-particle cryo-electron microscopy analysis at near-atomic resolution. This is an example of a shared receptor structure between a mammalian virus and a bacterial toxin. Our structure shows that ANTXR1 decorates the outer surface of the SVV capsid and interacts with the surface-exposed BC loop and loop II of VP1, “the puff” of VP2 and “the knob” of VP3. Comparison of the receptor-bound capsid structure with the native capsid structure reveals that receptor binding induces minor conformational changes in SVV capsid structure, suggesting the role of ANTXR1 as an attachment receptor. Furthermore, our results demonstrate that the capsid footprint on the receptor is not conserved in anthrax toxin receptor 2 (ANTXR2), thereby providing a molecular mechanism for explaining the exquisite selectivity of SVV for ANTXR1.

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N-Linked Glycosylation on Anthrax Toxin Receptor 1 Is Essential for Seneca Valley Virus Infection

Viruses ◽

10.3390/v13050769 ◽

2021 ◽

Vol 13 (5) ◽

pp. 769

Author(s):

Nadishka Jayawardena ◽

Linde A. Miles ◽

Laura N. Burga ◽

Charles Rudin ◽

Matthias Wolf ◽

...

Keyword(s):

Transmembrane Protein ◽

Cancer Therapeutics ◽

Anthrax Toxin ◽

Mass Spectrometry Analysis ◽

Type I ◽

Post Translational Modification ◽

Spectrometry Analysis ◽

Toxin Receptor ◽

Seneca Valley Virus ◽

Complex Glycans

Seneca Valley virus (SVV) is a picornavirus with potency in selectively infecting and lysing cancerous cells. The cellular receptor for SVV mediating the selective tropism for tumors is anthrax toxin receptor 1 (ANTXR1), a type I transmembrane protein expressed in tumors. Similar to other mammalian receptors, ANTXR1 has been shown to harbor N-linked glycosylation sites in its extracellular vWA domain. However, the exact role of ANTXR1 glycosylation on SVV attachment and cellular entry was unknown. Here we show that N-linked glycosylation in the ANTXR1 vWA domain is necessary for SVV attachment and entry. In our study, tandem mass spectrometry analysis of recombinant ANTXR1-Fc revealed the presence of complex glycans at N166, N184 in the vWA domain, and N81 in the Fc domain. Symmetry-expanded cryo-EM reconstruction of SVV-ANTXR1-Fc further validated the presence of N166 and N184 in the vWA domain. Cell blocking, co-immunoprecipitation, and plaque formation assays confirmed that deglycosylation of ANTXR1 prevents SVV attachment and subsequent entry. Overall, our results identified N-glycosylation in ANTXR1 as a necessary post-translational modification for establishing stable interactions with SVV. We anticipate our findings will aid in selecting patients for future cancer therapeutics, where screening for both ANTXR1 and its glycosylation could lead to an improved outcome from SVV therapy.

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