Biology subjects

Yang, P. L.

Publications and source records attributed to Yang, P. L..

3 recordsLinked to original sources

bioRxiv2024

Discovery of Potent Degraders of the Dengue Virus Envelope Protein

Targeted protein degradation has been widely adopted as a new approach to eliminate both established and previously recalcitrant therapeutic targets. Here we report the development of small molecule degraders of the envelope (E) protein of dengue virus. We developed two classes of bivalent E-degraders, linking two previously reported E-binding small molecules, GNF-2 and CVM-2-12-2, to a glutarimide-based recruiter of the CRL4CRBN ligase to effect proteosome-mediated degradation of the E protein. ZXH-2-107 (based on GNF-2) is an E degrader with ABL inhibition while ZXH-8-004 (based on CVM-2-12-2) is a selective and potent E-degrader. These two compounds provide proof-of-concept that difficult-to-drug targets such as a viral envelope protein can be effectively eliminated using a bivalent degrader and provide starting points for the future development of a new class antiviral drugs.

biochemistry↗

bioRxiv2019

A Sensitive Yellow Fever Virus Entry Reporter Identifies Valosin-Containing Protein (VCP/p97) as an Essential Host Factor for Flavivirus Uncoating

While the basic mechanisms of flavivirus entry and fusion are understood, little is known about the post-fusion events that precede RNA replication, such as nucleocapsid disassembly. We describe here a sensitive, conditionally replication-defective yellow fever virus (YFV) entry reporter, YFV{Delta}SK/Nluc, to quantitively monitor the translation of incoming, virus particle-delivered genomes. We validated that YFV{Delta}SK/Nluc gene expression can be neutralized by YFV-specific antisera and requires known flavivirus entry pathways, including clathrin- and dynamin-mediated endocytosis, endosomal acidification, YFV E glycoprotein-mediated fusion, and cellular LY6E expression; however, as expected, gene expression from the defective reporter virus was insensitive to a small molecule inhibitor of YFV RNA replication. YFV{Delta}SK/Nluc gene expression was also shown to require cellular ubiquitylation, consistent with recent findings that dengue virus capsid protein must be ubiquitylated in order for nucleocapsid uncoating to occur, as well as valosin-containing protein (VCP)/p97, a cellular ATPase that unfolds and extracts ubiquitylated client proteins from large macromolecular complexes. RNA transfection and washout experiments showed that VCP/p97 functions at a post-fusion, pre-translation step in YFV entry. Together, these data support a critical role for VCP/p97 in the disassembly of incoming flavivirus nucleocapsids during a post-fusion step in virus entry.\n\nIMPORTANCEFlaviviruses are an important group of RNA viruses that cause significant human disease. The mechanisms by which flavivirus nucleocapsids are disassembled during virus entry remain unclear. Here we show that the yellow fever virus nucleocapsid disassembly requires the cellular protein-disaggregating enzyme valosin-containing protein, also known as p97.

microbiology↗

bioRxiv2018

How small-molecule inhibitors of dengue-virus infection interfere with viral membrane fusion

Dengue virus (DV) is a compact, icoshedrally symmetric, enveloped particle, covered by 90 dimers of envelope protein (E), which mediates viral attachment and membrane fusion. Fusion requires a dimer-to-trimer transition and membrane engagement of hydrophobic \"fusion loops\". We previously characterized the steps in membrane fusion for the related West Nile virus (WNV), using recombinant, WNV virus-like particles (VLPs) for single-particle experiments. Trimerization and membrane engagement are rate-limiting; fusion requires at least two adjacent trimers; availability of competent monomers within the contact zone between virus and target membrane creates a trimerization bottleneck. We have extended that work to dengue VLPs, from all four DV serotypes, finding an essentially similar mechanism. Small-molecule inhibitors of DV infection that target E block its fusion-inducing conformation change. We show that [~]15 bound molecules per particle ([~]8.5 % occupancy) completely prevent fusion, in accord with the proposed mechanism and the likely inhibitor binding site on E.\n\nImpact statementSingle-particle studies of dengue-virus membrane fusion and the effect of small-molecule inhibitors of infection clarify the viral fusion mechanism.

biophysics↗