Biology subjects

Thomas, C. E.

Publications and source records attributed to Thomas, C. E..

3 recordsLinked to original sources

bioRxiv2026

HIV-1 Nef Homodimerization as a Structural Mechanism for Kinase Activation and Small Molecule Inhibitor Action

The HIV-1 accessory protein Nef plays a central role in viral pathogenesis by enhancing viral replication, modulating cellular signaling, and evading immune recognition, making it a compelling target for therapeutic intervention. Nef lacks enzymatic activity and instead functions through diverse interactions with host cell proteins including the Src-family tyrosine kinase, Hck. Kinase activation may requires Nef homodimerization, as mutations disrupting the Nef dimer interface impair kinase activation as well as many other Nef functions. In the present study, we investigated the structural consequences of dimer interface mutations and their impact on Nef interactions with Hck regulatory domains. Using size-exclusion chromatography, multi-angle light scattering and crystallography, we found that mutations at dimer interface residues Leu112 and Phe121 abolish recombinant Nef protein dimerization while preserving the overall Nef fold, resulting in monomeric 1:1 complexes with Hck SH3 or SH3-SH2 domain proteins. These findings demonstrate that the broad phenotypic effects of interface mutations arise from loss of Nef dimerization rather than global misfolding or perturbation of SH3 binding. We also investigated the effects of small molecule Nef inhibitors on homodimer formation. These compounds, like the dimerization-defective mutations, suppress kinase activation, viral replication and restore immune recognition of HIV-infected cells. Using a SplitFAST fluorescence complementation assay, we provide direct evidence that these inhibitors disrupt Nef homodimer formation in solution. Co-crystallization of a wild-type Nef:SH3 complex with an inhibitor also prevented homodimer formation. Computational docking identified a shared pocket for six active Nef inhibitors formed by the Nef dimer interface but lost in the monomer. Together, our findings support homodimerization as a structural feature essential for many Nef functions and validate disruption of this interface as a promising therapeutic strategy against HIV-1.

microbiology↗

bioRxiv2021

Circulating proteins reveal prior use of menopausal hormonal therapy and increased risk of breast cancer

BackgroundRisk prediction is crucial for early detection and prognosis of breast cancer. Circulating plasma proteins could provide a valuable source to increase the validity of risk prediction models, however, no such markers have yet been identified for clinical use. MethodsEDTA plasma samples from 183 breast cancer cases and 366 age-matched controls were collected prior to diagnosis from the Swedish breast cancer cohort KARMA. The samples were profiled on 700 circulating proteins using an exploratory affinity proteomics approach. Linear association analyses were performed on case-control status and a data-driven analysis strategy was applied to cluster the women on their plasma proteome profiles in an unsupervised manner. The resulting clusters were subsequently annotated for the differences in phenotypic characteristics, clinical parameters, and genetic risk. ResultsUsing the data-driven approach we identified five clusters with distinct proteomic plasma profiles. Women in a particular sub-group (cluster 1) were significantly more likely to have used menopausal hormonal therapy (MHT), more likely to get a breast cancer diagnosis, and were older compared to the remaining clusters. The levels of circulating proteins in cluster 1 were decreased for proteins related to DNA repair and cell replication and increased for proteins related to mammographic density and female tissues. In contrast, classical dichotomous case-control analyses did not reveal any proteins significantly associated with future breast cancer. ConclusionUsing a data-driven approach, we identified a subset of women with circulating proteins associated with previous use of MHT and risk of breast cancer. Our findings point to the potential long-lasting effects of MHT on the circulating proteome even after ending the treatment, and hence provide valuable insights concerning risk predication of breast cancer. HighlightsO_LICurrent risk prediction models use a variety of factors to identify women at risk of developing breast cancer. C_LIO_LIProteins circulating in blood represent an attractive but currently still underrepresented source of candidates serving as molecular risk factors. C_LIO_LIPlasma proteomes from women participating in a prospective breast cancer cohort study were studied for proteomic risk factors related to a future breast cancer diagnosis. C_LIO_LIUsing data-driven approaches, women with future breast cancers and previous use of menopausal hormone therapy were identified based on their circulating proteins. C_LIO_LIMenopausal hormone therapy was found to altered the levels of the circulating proteins even years after the treatment ended. C_LI

systems biology↗

bioRxiv2021

In-silico Structural and Molecular Docking-Based Drug Discovery Against Viral Protein (VP40) of Marburg Virus: A Causative Agent of MAVD

The Marburg virus (MARV) is reported to induce extreme hemorrhagic fever (MHF) with a high degree of infectivity and lethality in both human and non-human primates. An appropriate vaccination for this viruss treatment is not yet usable, and thus needs intensive attempts on multiple scales. In this study, we employed the Computer-Aided Drug Design (CADD) based approach to identify the drug-like compounds inhibiting the replication of the Viral protein (VP40) of MARV. Our database search using an online database "PubChem" retrieved [~]3000 compounds structure-based similarity. Lipinskis rule was applied to evaluate further the drug-like compounds, followed by molecular docking-based screening, and the selection of screening ligand complex with VP40 based on S-score (lower than reference Favipiravir inhibitor) and root-mean-square-deviation (RMSD) value (probably less than 2) using AutoDock 4.2. Resultantly, [~]100 compounds were identified having strong interaction with VP40 of MARV. After evaluating their binding energy using the AutoDock 4.2 software, four compounds (CID-67534452, CID-72201087, CID-123273976, CID-153708661) were identified that showed strongest binding energy with VP40 of MARV and strong inhibition effect than the Favipiravir. Robust binding energy, useful ADMET parameters and drug-likeness suggest that these candidates "CID-67534452, CID-72201087, CID-123273976, CID-153708661" have tremendous potential to stop the replication of MARV, hence might lead to the cure of MAVD.

bioinformatics↗