Biology subjects

Manon, V.

Publications and source records attributed to Manon, V..

4 recordsLinked to original sources

bioRxiv2025

A Structural Atlas of TAP Inhibition by Herpesviruses and Poxviruses

In the host-pathogen arms race, herpesviruses and poxviruses encode proteins that sabotage the transporter associated with antigen processing (TAP), thereby suppressing MHC-I antigen presentation and enabling lifelong infection. Of the five known viral TAP inhibitors, only the herpes simplex virus protein ICP47 has been structurally resolved. We now report cryo-electron microscopy structures of TAP in complex with the remaining four: BNLF2a (Epstein-Barr virus), hUS6 (human cytomegalovirus), bUL49.5 (bovine herpesvirus 1), and CPXV012 (cowpox virus), assembling a structural atlas of viral TAP evasion. Employing divergent sequences, folds and conformational targets, these viral inhibitors converge on a common strategy: they stall TAP from the alternating access cycle, precluding peptide entry into the ER and shielding infected cells from cytotoxic T-cell surveillance. These findings reveal striking functional convergence and provide a structural framework for rational antiviral design.

biophysics↗

bioRxiv2025

Nucleotide-dependent conformational changes direct peptide export by the transporter associated with antigen processing

The transporter associated with antigen processing (TAP) is essential for adaptive immunity, delivering peptide antigens from the cytoplasm into the endoplasmic reticulum (ER) for loading onto MHC-I molecules. Previous studies have revealed the mechanism by which TAP selectively binds peptides while allowing for sequence diversity, but how the bound peptides are transported and released into the ER is not yet fully understood. Here, we report cryo-electron microscopy structures of human TAP in multiple functional states along the transport cycle. In the inward-facing conformation, ATP binding strengthens intradomain assembly. The transition to the outward-facing conformation is highly temperature-dependent and leads to a complete reconfiguration of the peptide-binding site, facilitating peptide release. ATP hydrolysis opens the consensus site, and the subsequent separation of the NBDs resets the transport cycle. These findings establish a comprehensive structural framework for understanding the mechanisms of peptide transport, vanadate trapping, and trans-inhibition.

biophysics↗

bioRxiv2024

Functional classification of tauopathy strains reveals the role of protofilament core residues.

Distinct tau amyloid assemblies underlie diverse tauopathies but defy rapid classification. Cell and animal experiments indicate tau functions as a prion, as different strains propagated in cells cause unique, transmissible neuropathology after inoculation. Strain amplification requires compatibility of the monomer and amyloid template. We used cryo-EM to study one cell-based YFP-tagged strain, resolving its amyloid nature. We then used sequential alanine (Ala) substitution (scan) within tau repeat domain (RD) to measure incorporation to pre-existing tau RD-YFP aggregates. This robustly discriminated strains, defining sequences critical for monomer incorporation. We then created 3R/4R or 4R WT RD (aa 246-408) biosensors. Ala scan of recombinant tau seeds with the Alzheimers Disease fold matched that of AD homogenate. We scanned 22 brain lysates comprising 4 tauopathies. This clustered cases by neuropathological syndrome, revealed the role of amino acids in protofilament folds, and allowed strain discrimination based on amino acid requirements for prion replication. TeaserDiscrimination of tau strains based on the relative contribution of each amino acid to templated propagation of the amyloid.

neuroscience↗

bioRxiv2023

The principles of peptide selection by the transporter associated with antigen processing

The adaptive immune response eliminates infected and cancer cells through the recognition of antigenic peptides displayed by major compatibility complex class I (MHC-I) molecules1, 2. A single transporter, the transporter associated with antigen processing (TAP), supplies nearly the entire peptide repertoire for the many MHC-I alleles3-5. A fundamental unresolved question is how TAP transports peptides with vast sequence diversity. Here, using cryo-electron microscopy (cryo-EM), we determined seven structures of human TAP in the presence and absence of peptides with different sequences and lengths. We observe that peptides are suspended in the transmembrane cavity of TAP with the peptide N-and C-termini anchored at two distal binding pockets. The central residues of the peptide are unrestricted, making few contacts with TAP. A minimum of eight residues is required to bridge the two binding pockets, aligning with the lower length limit for MHC-I binding6, 7. Mutations in TAP that disrupt hydrogen bonds with the peptide termini nearly abolish MHC-I surface expression, indicating that binding depends on interactions with mainchain atoms at the two termini. By utilizing two spatially separated binding pockets and concentrating interactions at the two ends of the peptide, TAP functions as a molecular caliper, selecting peptides for length while permitting sequence diversity.

biophysics↗