Biology subjects

Williamson, N.

Publications and source records attributed to Williamson, N..

3 recordsLinked to original sources

bioRxiv2025

Global analysis of cancer cell responses to USP9X inhibition

The ubiquitin specific protease (USP) enzyme USP9X is amongst the best studied human deubiquitinases (DUBs), with a myriad of described targets and cellular roles. In cancer, USP9X has been touted as both an oncogene and a tumour suppressor in different contexts, which has confounded the field and questioned its viability as a cancer target. We here describe WEHI-092, a novel piperazine-based USP9X specific small molecule inhibitor and map its binding site to a unique region in the USP9X fingers subdomain, distinct from known DUB inhibitor binding sites. Using proteomics and ubiquitinomics, we show that USP9X has a distinct set of substrates compared to USP7 indicating remarkable DUB target specificity, yet the substrate profile of USP9X varies significantly across cancer cell lines. Interestingly, we reveal a core set of 17 proteins commonly regulated by USP9X in most or all cell lines, which we consider as proximal biomarkers for USP9X inhibition. Consistent with our proteomic analyses, we show that WEHI-092 treatment arrests cells in metaphase without inducing cell death, which may account for growth suppression seen in long-term clonogenic assays in most cancer cell lines, and positions USP9X inhibitors as a new potential class of selective mitotic poisons.

cell biology↗

bioRxiv2022

Respiratory strategy at birth initiates distinct lung injury phenotypes in the preterm lamb lung

Bronchopulmonary disease is the chronic manifestation of the acute injury that may accompany ventilation following preterm birth. A lack of clear trial evidence often hampers clinical decision-making during support of the preterm lung at birth. Protein biomarkers have been used to define acute lung injury phenotypes and improve patient selection for specific interventions in adult respiratory distress syndrome. Here we present a mass spectrometry-based approach to profile the protein phenotype associated with three different aeration strategies known to cause different pathophysiological responses when applied at birth to preterm lambs. We were able to identify pathway enrichments specific to both ventilation strategy and lung regions based upon gravity-dependency. Ventilation strategy-specific phenotypes were further delineated by applying partial least square modelling to identify associations between specific proteins and clinical, physiological and morphological outcomes. This work highlights the specificity of lung injury responses to routinely applied birth interventions such as different respiratory support approaches and identified the molecular events associated with each. Furthermore, we demonstrate the capacity to subdivide preterm infants by the direct aetiology and response to lung injury; the first step towards true precision medicine in neonatology.

systems biology↗

bioRxiv2020

Discovery and characterisation of novel circular bacteriocin plantacyclin B21AG from Lactobacillus plantarum B21

Lactobacillus plantarum B21 isolated from Vietnamese sausage (nem chua) has previously displayed broad antimicrobial activity against gram positive bacteria including foodborne pathogens Listeria monocytogenes and Clostridium perfringens. This study successfully identified the antimicrobial agent as plantacyclin B21AG, a 5668 Da circular bacteriocin demonstrating high thermostability, resistance to a wide range of pH, proteolytic resistance and temporal stability. We report a reverse genetics approach used to identify and characterise plantacyclin B21AG. The bacteriocin was purified from culture supernatant by a short process consisting of concentration, n-butanol extraction and cation exchange chromatography. A de novo peptide sequencing using LC-MS/MS techniques identified two putative peptide fragments which were mapped to the genome of Lactobacillus plantarum B21. This revealed an ORF corresponding to a putative circular bacteriocin with a 33-amino acid leader peptide and 58-amino acid mature peptide found on native plasmid pB21AG01. The corresponding gene cluster, consisted of seven genes associated with post-translational circularisation, immunity and secretion. The robust nature of plantacyclin B21AG, its antimicrobial activity and associated machinery for cyclisation make it an interesting biotechnological target for further development, and application as a food-safe antimicrobial.

biochemistry↗