Biology subjects

Yousef, J.

Publications and source records attributed to Yousef, J..

5 recordsLinked to original sources

bioRxiv2026

Megakaryocytic proteomic signatures define myeloproliferative neoplasms

The classical Philadelphia-negative myeloproliferative neoplasms (MPNs) are clonal stem cell disorders of the bone marrow with significant niche dysregulation driven in part by abnormal megakaryocytes. The three classical MPNs: polycythemia vera (PV), essential thrombocythemia (ET) and primary myelofibrosis (PMF), display established megakaryocytic morphological differences which aid in their diagnostic classification. The paucity of megakaryocytes in the bone marrow aspirate has previously limited a proteomic analysis of megakaryocytes in clinical samples. We aimed to undertake an unbiased proteomic analysis of in situ megakaryocytes from the bone marrow of patients with PV, ET, and PMF. Using a novel, deep visual proteomics strategy, we dissected and analyzed megakaryocytes from 60 MPN patients and 20 controls (patients with limited stage non-Hodgkin lymphoma who had uninvolved bone marrow). We reveal that megakaryocyte proteomics from MPN patients are distinct to those from control patients, and further, that the megakaryocytes from the three MPNs have unique, disease-specific signatures. The disease-specific megakaryocyte proteome highlights novel pathways of disease.

cancer biology↗

bioRxiv2024

PSKH1 kinase activity is differentially modulated via allosteric binding of Ca2+ sensor proteins

Protein Serine Kinase H1 (PSKH1) was recently identified as a crucial factor in kidney development and is overexpressed in prostate, lung and kidney cancers. However, little is known about PSKH1 regulatory mechanisms, leading to its classification as a "dark" kinase. Here, we used biochemistry and mass spectrometry to define PSKH1s consensus substrate motif, protein interactors, and how interactors, including Ca2+ sensor proteins, promote or suppress activity. Intriguingly, despite the absence of a canonical Calmodulin binding motif, Ca2+-Calmodulin activated PSKH1 while, in contrast, the ER-resident Ca2+ sensor of the CREC family, Reticulocalbin-3, suppressed PSKH1 catalytic activity. In addition to antagonistic regulation of the PSKH1 kinase domain by Ca2+ sensing proteins, we identified UNC119B as a protein interactor that activates PSKH1 via direct engagement of the kinase domain. Our findings identify complementary allosteric mechanisms by which regulatory proteins tune PSKH1s catalytic activity, and raise the possibility that different Ca2+ sensors may act more broadly to tune kinase activities by detecting and decoding extremes of intracellular Ca2+ concentrations.

biochemistry↗

bioRxiv2024

MORC2 phosphorylation fine tunes its DNA compaction activity

Variants in the poorly characterised oncoprotein, MORC2, a chromatin remodelling ATPase, lead to defects in epigenetic regulation and DNA damage response. The C-terminal domain (CTD) of MORC2, frequently phosphorylated in DNA damage, promotes cancer progression, but its role in chromatin remodelling remains unclear. Here, we report a molecular characterisation of full-length, phosphorylated MORC2, demonstrating its preference for binding open chromatin and functioning as a DNA sliding clamp. We identified a phosphate interacting motif within the CTD that dictates ATP hydrolysis rate and cooperative DNA binding. The DNA binding impacts several structural domains within the ATPase region. We provide the first visual proof that MORC2 induces chromatin remodelling through ATP hydrolysis-dependent DNA compaction, regulated by its phosphorylation state. These findings highlight phosphorylation of MORC2 CTD as a key modulator of chromatin remodelling, presenting it as a potential therapeutic target.

molecular biology↗

bioRxiv2023

Scanning ultrasound improves memory and enhances functional outcomes in Alzheimer mice in the absence of amyloid-beta reduction

A prevalent view in treating age-dependent disorders including Alzheimers disease (AD) is that the underlying amyloid plaque pathology must be targeted for cognitive improvements. In contrast, we report here that repeated scanning ultrasound (SUS) treatment at 1 MHz frequency can ameliorate memory deficits in the APP23 mouse model of AD without reducing amyloid-{beta} (A{beta}) burden. Different from previous studies that had shown A{beta} clearance as a consequence of blood-brain barrier (BBB) opening, here, the BBB was not opened as no microbubbles were used. Quantitative proteomics and functional magnetic resonance imaging revealed that ultrasound induced long-lasting functional changes that correlate with the improvement in memory. Intriguingly, the treatment was more effective at a higher frequency (1MHz) than at a frequency within the range currently explored in clinical trials in AD patients (286 kHz). Together, our data suggest frequency-dependent bio-effects of ultrasound and a dissociation of cognitive improvement and A{beta} clearance, with important implications for the design of trials for AD therapies. SummaryThe therapeutic effect of ultrasound on memory in AD mice leads to altered protein expression and improved functional connectivity in the absence of amyloid-{beta} removal. Of two frequencies explored, the higher ultrasound frequency (1 MHz) is more effective.

neuroscience↗

bioRxiv2022

TGF-beta1 induced S100 family protein expression is associated with epithelial to mesenchymal transition states and poor survival in pancreatic cancer

Epithelial-mesenchymal transition (EMT) is a continuum that includes epithelial, partial EMT (P-EMT) and mesenchymal states, each of which are associated with cancer progression, invasive capabilities and ultimately metastasis. We have employed a lineage traced sporadic model of pancreatic cancer to generate a murine organoid biobank from primary and secondary tumors, including sublines that have undergone P-EMT and complete EMT (C-EMT). Using an unbiased proteomics approach, we found that the morphology of the organoids predicts the EMT state, with solid organoids associated with a P-EMT signature. We also observed that exogenous TGF{beta}1 induces a solid organoid morphology that is associated with changes in the S100 family, C-EMT and the formation of high-grade tumors. S100A4 may represent a useful biomarker to predict EMT state, disease progression and outcome for pancreatic cancer patients.

cancer biology↗