Structures of HCMV Trimer reveal the basis for receptor recognition and cell entry

Kschonsak, Marc; Rougé, Lionel; Arthur, Christopher P.; Ho, Hoangdung; Patel, Nidhi; Kim, Ingrid; Johnson, Matthew C.; Kraft, E; Rohou, Alexis; Gill, Avinash; Martínez‐Martín, Nadia; Payandeh, Jian; Ciferri, Claudio

doi:10.1016/j.cell.2021.01.036

Cited by 36 publications

(65 citation statements)

References 64 publications

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“…Due to the importance of these cell types during natural infection, this represents a critical advance in our understanding of how HCMV engages host cells at one of the earliest stages of infection 22,46 . Similarly, the structure of the HCMV Trimer was recently reported in complex with PDGFRα and TGFβR3, two host cell receptors that both mediate tropism of fibroblasts 18,20 . In an effort to explain how this interaction might lead to triggering of gB and viral fusion, the authors speculate that receptor engagement of the Trimer may induce a rigid-body rotation relative to the viral membrane that causes the attachment complex to destabilize prefusion gB 47 .…”

Section: Main Textmentioning

confidence: 57%

“…The HCMV Trimer mediates tropism for fibroblasts by binding platelet derived growth factor receptor alpha (PDGFRα) 18, 19 . The HCMV Trimer is also capable of mediating infection of a broader variety of cell types by interacting with transforming growth factor beta receptor 3 (TGFβR3) 4, 20 . The other critical tropism-determining complex is the HCMV Pentamer, which is composed of glycoproteins UL128, UL130, UL131, and the same gH and gL proteins that comprise the bulk of the HCMV Trimer 1, 3 .…”

Section: Main Textmentioning

confidence: 99%

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Structural basis for HCMV Pentamer recognition by antibodies and neuropilin 2

Wrapp

et al. 2021

Preprint

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Human cytomegalovirus (HCMV) encodes for multiple surface glycoproteins and glycoprotein complexes. One of these complexes, the HCMV Pentamer (gH, gL, UL128, UL130 and UL131), mediates tropism to both epithelial and endothelial cells by interacting with the cell surface receptor neuropilin 2 (NRP2). Despite the critical nature of this interaction, the molecular determinants that govern NRP2 recognition remain unclear. Here we describe the cryo-EM structure of NRP2 bound to the HCMV Pentamer. The high-affinity interaction between these proteins is calcium-dependent and differs from the canonical C-terminal arginine (CendR) binding that NRP2 typically utilizes. The interaction is primarily mediated by NRP2 domains a2 and b2, which interact with UL128 and UL131. We also determine the structures of four human-derived neutralizing antibodies in complex with the HCMV Pentamer to define susceptible epitopes. The two most potent antibodies recognize a novel epitope yet do not compete with NRP2 binding. Collectively, these findings provide a structural basis for HCMV tropism and antibody-mediated neutralization, and serve as a guide for the development of HCMV treatments and vaccines.

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Section: Main Textmentioning

confidence: 57%

Section: Main Textmentioning

confidence: 99%

Structural basis for HCMV Pentamer recognition by antibodies and neuropilin 2

Wrapp

et al. 2021

Preprint

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“…The S48Y mutation that conferred a moderate level of resistance against PDGFRα-Fc sensitized the virus for inhibition by GT40, indicating that this part of gO is involved in the interaction of this peptide with the virus. In line with this assumption, selection with GT40 induced the mutation L47P in the neighboring amino acid, and recent structural data also show that GT40 is located in a loop of domain 2 within PDGFRα that includes three of the five hydrophobic residues in the designated interaction site 3 that are directed to a hydrophobic groove at the N terminus of gO [21]. IK40 locates directly at interaction site 4 within domain 3 of PDGFRα, which interacts with the C-terminal part of gO [21], and therefore it appears plausible that its inhibitory potential is not affected by a mutation in the N-terminus of gO.…”

Section: Discussionmentioning

confidence: 68%

“…The serine to tyrosine mutation at position 48 in the N-terminus of gO that reduced sensitivity to PDGFRα-Fc by about three-fold is located close to a region of this protein that has previously been identified as relevant for receptor binding in a mutational scanning approach [20], providing further support for the functional relevance of the N-terminus. The structure of gO bound to PDGFRα has been resolved by cryo-electron microscopy, and these data indicate that the N-terminus of gO interacts with domain 2 of the receptor [21], which has been identified as relevant for inhibition of HCMV by multiple approaches [9,12,19,22]. As we did not find evidence for a reduced fitness of the mutant virus, i.e., virus titers did not differ from wildtype virus (Figure S1), it is tempting to speculate that subtle differences between the receptor on the cell surface and the soluble Fc-chimera exist that allow slightly reduced binding of the inhibitor while receptor-binding of the virus is unaffected.…”

Section: Discussionmentioning

confidence: 99%

Selection of Human Cytomegalovirus Mutants with Resistance against PDGFRα-Derived Entry Inhibitors

Sampaio¹,

Lutz²,

Engels³

et al. 2021

Viruses

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The human cytomegalovirus (HCMV) infects fibroblasts via an interaction of its envelope glycoprotein gO with the cellular platelet-derived growth factor receptor alpha (PDGFRα), and soluble derivatives of this receptor can inhibit viral entry. We aimed to select mutants with resistance against PDGFRα-Fc and the PDGFRα-derived peptides GT40 and IK40 to gain insight into the underlying mechanisms and determine the genetic barrier to resistance. An error-prone variant of strain AD169 was propagated in the presence of inhibitors, cell cultures were monitored weekly for signs of increased viral growth, and selected viruses were tested regarding their sensitivity to the inhibitor. Resistant virus was analyzed by DNA sequencing, candidate mutations were transferred into AD169 clone pHB5 by seamless mutagenesis, and reconstituted virus was again tested for loss of sensitivity by dose-response analyses. An S48Y mutation in gO was identified that conferred a three-fold loss of sensitivity against PDGFRα-Fc, a combination of mutations in gO, gH, gB and gN reduced sensitivity to GT40 by factor 4, and no loss of sensitivity occurred with IK40. The resistance-conferring mutations support the notion that PDGFRα-Fc and GT40 perturb the interaction of gO with its receptor, but the relatively weak effect indicates a high genetic barrier to resistance.

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“…Consequently, the PDGFRα mutational landscape failed to unambiguously highlight a surface epitope for modeling. A recently solved high-resolution structure of PDGFR-bound HCMV trimer shows why; the binding interface is extensive and spread over three receptor domains, such that disruption of interactions by any one receptor domain has minimal impact on HCMV trimer binding (Kschonsak et al, 2021).…”

Section: Deep Mutagenesis Of Host Receptors: Implications Of Human Polymorphisms and Engineered Receptors As Therapeuticsmentioning

confidence: 99%

Deep Mutational Scanning of Viral Glycoproteins and Their Host Receptors

Narayanan

Procko

2021

Front. Mol. Biosci.

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Deep mutational scanning or deep mutagenesis is a powerful tool for understanding the sequence diversity available to viruses for adaptation in a laboratory setting. It generally involves tracking an in vitro selection of protein sequence variants with deep sequencing to map mutational effects based on changes in sequence abundance. Coupled with any of a number of selection strategies, deep mutagenesis can explore the mutational diversity available to viral glycoproteins, which mediate critical roles in cell entry and are exposed to the humoral arm of the host immune response. Mutational landscapes of viral glycoproteins for host cell attachment and membrane fusion reveal extensive epistasis and potential escape mutations to neutralizing antibodies or other therapeutics, as well as aiding in the design of optimized immunogens for eliciting broadly protective immunity. While less explored, deep mutational scans of host receptors further assist in understanding virus-host protein interactions. Critical residues on the host receptors for engaging with viral spikes are readily identified and may help with structural modeling. Furthermore, mutations may be found for engineering soluble decoy receptors as neutralizing agents that specifically bind viral targets with tight affinity and limited potential for viral escape. By untangling the complexities of how sequence contributes to viral glycoprotein and host receptor interactions, deep mutational scanning is impacting ideas and strategies at multiple levels for combatting circulating and emergent virus strains.

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Structures of HCMV Trimer reveal the basis for receptor recognition and cell entry

Cited by 36 publications

References 64 publications

Structural basis for HCMV Pentamer recognition by antibodies and neuropilin 2

Structural basis for HCMV Pentamer recognition by antibodies and neuropilin 2

Selection of Human Cytomegalovirus Mutants with Resistance against PDGFRα-Derived Entry Inhibitors

Deep Mutational Scanning of Viral Glycoproteins and Their Host Receptors

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