Biology subjects

Pellowe, G. A.

Publications and source records attributed to Pellowe, G. A..

5 recordsLinked to original sources

bioRxiv2026

Cross-omics profiling reveals cortical neuronal dysfunction following neonatal intraventricular haemorrhage that is attenuated by decorin treatment

Neonatal intraventricular haemorrhage (IVH) is a form of haemorrhagic stroke which is most common in premature infants and can cause mortality and lifelong disability. The reaction of brain tissue to extraneous blood is known to trigger several complications including post-haemorrhagic hydrocephalus (PHH), furthering the likelihood of neurological disability and death. The molecular response of the neuron-rich cortex to blood within the first 24 hours of injury, and how this may precipitate secondary brain injury or neurodegeneration, remains poorly defined. This lack of understanding may reduce the development of novel therapeutics aiming to limit the injury caused by neonatal IVH. Here, we utilised a proteome and transcriptome cross-omics approach to characterise cortical responses to blood in a neonatal mouse model of IVH to improve understanding of the effects and drivers of IVH-induced brain injury. The pleiotropic proteoglycan decorin, a well-characterised modulator of the inflammatory cytokine transforming growth factor beta 1, was also studied to identify if it can have any beneficial effects in the cortex. Cross-omics analysis between the transcriptome and proteome highlighted ferroptosis-associated signatures as a key post-IVH cortical injury mechanism. IVH caused a marked depletion of cortical neurons, neurofilaments, and synaptic vesicle proteins, observed through transcriptomics, immunostaining, and proteomics, which were attenuated by decorin treatment. Decorin also produced an enhanced phagocytic response potentially through activation of microglia. These findings highlight the vulnerability of cortical neurons to early injury following IVH in neonates and support decorin as a potential neuroprotective agent. They also suggest that ferroptosis-associated pathways may contribute to early cortical injury and represent a potential therapeutic target in this context.

neuroscience↗

bioRxiv2026

Molecular determinants of cotranslational chaperone recruitment to nascent p53

Protein folding is fast relative to mRNA translation and nascent polypeptides begin to fold during their synthesis on the ribosome. The resulting cotranslational folding intermediates are accessible to diverse molecular chaperones that recognise incompletely folded client proteins. Here, we sought to understand how specific chaperone:client complexes are established during protein synthesis, using the chaperone-dependent tumor suppressor protein p53 as a model. By capturing interactomes at different points during p53 synthesis, we show that Hsp70, Hsp90 and TRiC bind competitively to nascent p53. While Hsp70 and Hsp90 bind promiscuously, TRiC discriminates between subtly different partially-folded states. TRiC recruitment is dictated by local cotranslational folding and exposure of specific sequence motifs, and this is tuned by cancer-associated mutations in the p53 DNA-binding domain. Nascent chain interactions with the ribosome surface disfavor TRiC binding, demonstrating that the ribosome imposes unique constraints on chaperone recruitment during protein synthesis. Our results establish molecular principles underlying chaperone prioritization during protein biogenesis.

biochemistry↗

bioRxiv2024

The human ribosome modulates multidomain protein biogenesis by delaying cotranslational domain docking

Proteins with multiple domains are intrinsically prone to misfold, yet fold efficiently during their synthesis on the ribosome. This is especially important in eukaryotes, where multidomain proteins predominate. Here, we sought to understand how multidomain protein folding is modulated by the eukaryotic ribosome. We used cryo-electron microscopy and hydrogen/deuterium exchange-mass spectrometry to characterise the structure and dynamics of partially-synthesised intermediates of a model multidomain protein. We find that nascent subdomains fold progressively during synthesis on the human ribosome, templated by interactions across domain interfaces. The conformational ensemble of the nascent chain is tuned by its unstructured C-terminal segments, which keep interfaces between folded domains in dynamic equilibrium until translation termination. This contrasts with the bacterial ribosome, on which domain interfaces form early and remain stable during synthesis. Delayed domain docking may avoid interdomain misfolding to promote the maturation of multidomain proteins in eukaryotes.

biochemistry↗

bioRxiv2024

Mechanism of chaperone coordination during cotranslational protein folding in bacteria

Protein folding is assisted by molecular chaperones that bind nascent polypeptides during mRNA translation. Several structurally-distinct classes of chaperone promote de novo folding, suggesting that their activities are coordinated at the ribosome. We used biochemical reconstitution and structural proteomics to explore the molecular basis for cotranslational chaperone action in bacteria. We found that chaperone binding is disfavoured close to the ribosome, allowing folding to precede chaperone recruitment. Trigger factor subsequently recognises compact folding intermediates exposing extensive non-native surface and dictates DnaJ access to nascent chains. DnaJ uses a large surface to bind structurally diverse intermediates, and recruits DnaK to sequence-diverse solvent-accessible sites. Neither Trigger factor, DnaJ nor DnaK destabilize cotranslational folding intermediates. Instead, the chaperones collaborate to create a protected space for protein maturation that extends well beyond the ribosome exit tunnel. Our findings show how the chaperone network selects and modulates cotranslational folding intermediates.

biochemistry↗

bioRxiv2020

Hydrogen-deuterium exchange mass spectrometry captures distinct dynamics upon substrate and inhibitor binding to a transporter

Proton-coupled transporters use transmembrane proton gradients to power active transport of nutrients inside the cell. High-resolution structures often fail to capture the coupling between proton and ligand binding, and conformational changes associated with transport. We combine HDX-MS with mutagenesis and MD simulations to dissect the molecular mechanism of the prototypical transporter XylE. We show that protonation of a conserved aspartate triggers conformational transition from outward-facing to inward-facing state. This transition only occurs in the presence of substrate xylose, while the inhibitor glucose locks the transporter in the outward-facing state. MD simulations corroborate the experiments by showing that only the combination of protonation and xylose binding, and not glucose, sets up the transporter for conformational switch. Overall, we demonstrate the unique ability of HDX-MS to distinguish between the conformational dynamics of inhibitor and substrate binding, and show that a specific allosteric coupling between substrate binding and protonation is a key step to initiate transport.

biochemistry↗