@article{kaur_park_lewis_haugh_2006, title={Quantitative model of Ras-phosphoinositide 3-kinase signalling cross-talk based on co-operative molecular assembly}, volume={393}, ISSN={["1470-8728"]}, DOI={10.1042/bj20051022}, abstractNote={In growth-factor-stimulated signal transduction, cell-surface receptors recruit PI3Ks (phosphoinositide 3-kinases) and Ras-specific GEFs (guanine nucleotide-exchange factors) to the plasma membrane, where they produce 3′-phosphorylated phosphoinositide lipids and Ras-GTP respectively. As a direct example of pathway networking, Ras-GTP also recruits and activates PI3Ks. To refine the mechanism of Ras–PI3K cross-talk and analyse its quantitative implications, we offer a theoretical model describing the assembly of complexes involving receptors, PI3K and Ras-GTP. While the model poses the possibility that a ternary receptor–PI3K–Ras complex forms in two steps, it also encompasses the possibility that receptor–PI3K and Ras–PI3K interactions are competitive. In support of this analysis, experiments with platelet-derived growth factor-stimulated fibroblasts revealed that Ras apparently enhances the affinity of PI3K for receptors; in the context of the model, this suggests that a ternary complex does indeed form, with the second step greatly enhanced through membrane localization and possibly allosteric effects. The apparent contribution of Ras to PI3K activation depends strongly on the quantities and binding affinities of the interacting molecules, which vary across different cell types and stimuli, and thus the model could be used to predict conditions under which PI3K signalling is sensitive to interventions targeting Ras.}, number={1}, journal={BIOCHEMICAL JOURNAL}, publisher={Portland Press Ltd.}, author={Kaur, H and Park, CS and Lewis, JM and Haugh, JM}, year={2006}, month={Jan}, pages={235–243} }
 @article{kaur_jaso-friedmann_evans_2004, title={Single base oligodeoxyguanosine upregulates Fas ligand release by nonspecific cytotoxic cells}, volume={28}, ISSN={["1879-0089"]}, DOI={10.1016/j.dci.2003.09.015}, abstractNote={Nonspecific cytotoxic cells (NCC) are a type of teleost NK-like cell. In the present study a novel stimulus secretion model is described for catfish NCC utilizing single base oligodeoxyguanosine. Binding of guanosine 20-mers (dG20) to NCC up-regulated expression of cytosolic FasL detected by an anti-human FasL monoclonal antibody (mab). In vitro treatment of purified NCC with dG20 produced a 7-fold increase in expression of soluble Fas ligand (sFasL) after 3 h. Antibody binding to NCC was saturable and approximately 30-35% of total NCC were positive for sFasL expression. The teleost FasL equivalent produced programmed cell death of appropriate FasR positive targets. Supernatants from dG20 activated NCC produced hypoploidy and annexin-V binding by FasR bearing HL-60 cells. Treatment of activated supernatants with immobilized anti-FasL mab neutralized these activities. These studies demonstrated that an NK like cell (NCC) produces and secretes sFasL following binding by single base oligodeoxyguanosine.}, number={6}, journal={DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY}, author={Kaur, H and Jaso-Friedmann, L and Evans, DL}, year={2004}, month={May}, pages={571–579} }