Biology subjects

McNally, R.

Publications and source records attributed to McNally, R..

4 recordsLinked to original sources

bioRxiv2026

Vault Packaging Dynamics: Cargo Loading Stabilizes MVP Conformation for High-Payload Cytokine Delivery in Cancer Therapy

Recombinant vaults are dynamic protein cages with a large interior volume that can encapsulate therapeutic cargo. Using integrative cryogenic electron microscopy (cryoEM), cryogenic electron tomography (cryoET) and charge-detection mass spectrometry (CDMS), we characterized recombinant empty and interleukin-2 (IL-2)-packaged human vaults produced in yeast to define assembly, packaging heterogeneity and conformational dynamics relevant to optimized cancer and immune therapeutics. CryoEM maps at 2.79 angstrom (packaged) and 3.16 angstrom (empty) reveal a D39-symmetric barrel built from 78 major vault protein (MVP) subunits each with an interaction domain (INT) that anchors a cargo on the inner surface at MVP repeats R3-R4. CDMS deconvolution of empty versus packaged particles yields two IL-2-INT vault populations centered near 100 and 400 molecules per vault, with a maximum of ~660 copies/vault (i.e., many more copies than the 78 available INT anchors), matching cryoET estimates of ~150-600. Both methods show that highly packaged vaults are enlarged and distorted. Empty particles are conformationally flexible, which promotes initial cargo entry; loading then stabilizes the barrel and condenses cargo, producing vaults that each contain many hundreds of IL-2 molecules. These data establish the structural basis of vault encapsulation and a quantitative framework for engineering vault-based delivery vehicles.

cell biology↗

bioRxiv2023

Encapsulation of AAV into protein vault nanoparticles as a novel solution to gene therapy's neutralizing antibody problem

Although adeno-associated virus (AAV) has enjoyed enormous success as a delivery modality for gene therapy, it continues to suffer from the high prevalence of preexisting neutralizing antibodies in human populations, limiting who can receive potentially life-saving treatments. In this regard, AAV therapies generally also must be administered as a single dose since neutralizing antibodies develop in patients who receive the virus. Strategies for circumventing these issues remain limited. As a novel solution, we employed SpyTag-SpyCatcher molecular glue technology to facilitate packaging of AAVs inside of recombinant protein vault nanoparticles. Vaults are endogenous particles produced by mammalian cells. We therefore hypothesized that they may shield packaged molecules from neutralizing antibodies. Vaults have previously been utilized to deliver drugs and proteins into cells, but our study represents the first time anyone has packaged an entire virus inside of a vault. We showed that our vaultAAV (VAAV) delivery vehicle transduces cells in the presence of anti-AAV neutralizing serum. VAAV is positioned as a new gene therapy delivery platform with potential to overcome the neutralizing antibody problem and perhaps even allow administration of multiple doses, expanding the scope of AAV treatments.

bioengineering↗

bioRxiv2022

Ingestible capsule for detecting labile inflammatory biomarkers in situ

Transient molecules in the gastrointestinal (GI) tract, such as nitric oxide and hydrogen sulfide, are key signals and mediators of inflammatory bowel disease (IBD). Because these molecules are extremely short-lived in the body, they are difficult to detect. To track these reactive molecules in the GI tract, we have developed a miniaturized device that integrates genetically-engineered probiotic biosensors with a custom-designed photodetector and readout chip. Leveraging the molecular specificity of living sensors, we genetically encoded bacteria to respond to IBD-associated molecules by luminescing. Low-power electronic readout circuits (nanowatt power) integrated into the device convert the light from just 1 L of bacterial culture into a wireless signal. We demonstrate biosensor monitoring in the GI tract of small and large animal models and integration of all components into a sub-1.4 cm3 ingestible form factor capable of supporting wireless communication. The wireless detection of short-lived, disease-associated molecules could support earlier diagnosis of disease than is currently possible, more accurate tracking of disease progression, and more timely communication between patient and their care team supporting remote personalized care.

synthetic biology↗

bioRxiv2019

Structural studies of the Tudor domain from the Bombyx homolog of Drosophila PAPI: Implication to piRNA biogenesis

PIWI proteins and their associated PIWI-interacting RNAs (piRNAs) play crucial roles in proper gametogenesis in animal gonads. Partner of PIWIs (PAPI) is one of the important piRNA biogenesis factors. PAPI contains a Tudor domain and tandem KH domains. The tudor domain specifically recognizes symmetrical-dimethylarginines (sDMAs) on PIWI proteins. BmPAPI, a Bombyx mori homolog of PAPI, is localized at the outer membrane of mitochondria and supports exonucleolytic trimming of piRNA precursors to form mature 3-end of piRNAs. To understand the structural basis of piRNA processing by BmPAPI, we present crystal structures of the apo- and sDMA-liganded Tudor domain of BmPAPI.

biophysics↗