Fixed-term
How do you sort proteins from a phagosome or macropinosome?
Details The engulfment of pathogens by phagocytic immune cells is key to protect the body from infection. This shares much of the same cellular machinery as the engulfment of extracellular fluid by macropinocytosis, which also helps immune cells survey for antigens, as well as enabling cancer cells to grow by feeding on extracellular proteins. However, in the process of engulfment, cells also take up part of their own surface. This means they have to retrieve their own proteins from the vesicles formed before they get destroyed along with the captured material. Our previous work has shown that if cells cannot do this, they can no longer function properly. The aim of this PhD project is to apply cutting-edge microscopy, genetics and biochemistry to understand the fundamental mechanisms of how cells process phagosomes and macropinosomes to retrieve membrane proteins and therefore sustain both immune and cancer cell function. Please apply for this project using this link: https://www.sheffield.ac.uk/postgraduate/phd/apply/applying Funding Notes This project is available for self-funded applicants only References Recent papers from our group: Buckley CM, Gopaldass N, Bosmani C, Johnston SA, Soldati T, Insall RH, King JS. WASH drives early recycling from macropinosomes and phagosomes to maintain surface phagocytic receptors. Proceedings of the National Academy of Sciences, USA. 2016 Oct 4;113(40):E5906-E5915 https://www.pnas.org/doi/abs/10.1073/pnas.1524532113 CM Buckley, R Potts, A Gueho, JH Vines, CJ Munn, BA Phillips, B Gilsbach, A Nikolaev, T Soldati, AJ Parnell, A Kortholt and JS King†. Coordinated Ras and Rac activity shapes macropinocytic cups and enables phagocytosis of geometrically diverse bacteria. Current Biology, 2020. 30, 2912–2926. https://www.cell.com/current-biology/fulltext/S0960-9822(20)30736-3 JH Vines, Maib, CM Buckley, A Gueho, Z Zhu, T Soldati, DH Murray, JS King†. A PI (3, 5) P2 reporter reveals PIKfyve activity and dynamics on macropinosomes and phagosomes. Journal of Cell Biology, 2023. 222 (9): e202209077. https://rupress.org/jcb/article/222/9/e202209077/214199 Apply Now
Why are rhizobial symbiosis genes mobile?
Details Rhizobia are nitrogen fixing symbionts of legumes. They are defined by their ability to establish intracellular infections within plant hosts where they fix atmospheric nitrogen, thus allowing legumes to grow without external nitrogen inputs. Surprisingly however, key bacterial genes required for this complex trait are ‘mobile’ i.e. encoded on plasmids or integrative and conjugative elements – DNA elements capable of infecting new bacterial hosts. Evidence suggests that many of these elements are actively mobilizing within rhizobial populations, suggesting that regular symbiosis gene transfer is part of the ecology of rhizobial symbionts. The reasons for this, and the impact it has on rhizobial evolution are unclear. Many key questions remain outstanding, e.g. ‘can symbiosis MGE transfer make anyone a symbiont?’, ‘what are the evolutionary consequences for bacterial genomes after acquiring this trait?’, ‘what environments select for symbiosis gene mobility?’ In this project we will use a combination of experimental evolution of rhizobia in the lab and in plant mesocosms alongside omics technologies such as genomics and transcriptomics and analysis of pre-existing datasets. You will learn techniques such as sterile microbiological culturing, molecular skills, bioinformatics and statistics. The project is flexible and can be guided by the interests of the student. Please apply for this project using this link: https://www.sheffield.ac.uk/postgraduate/phd/apply/applying Funding Notes Self or externally funded students only. References https://royalsocietypublishing.org/doi/10.1098/rstb.2020.0471 Apply Now
Investigating the role of Ect2 in pancreatic cancer cell proliferation and motility
Details Pancreatic ductal adenocarcinoma (PDAC) has a low survival rate and new therapies are urgently needed. The RhoGEF, Ect2, is frequently overexpressed in PDAC tumours and is associated with a poor prognosis. Ect2 modulates the contractility of the actin cytoskeleton by locally activating RhoA and plays a role in multiple cellular processes including cell division, DNA repair and cell migration. However, it’s not clear which of these roles are most important for its function in PDAC tumorigenesis. In addition, Ect2 is regulated by the YAP/TAZ mechano-sensitive signalling pathway and our preliminary data indicate that its subcellular localisation is altered when cells are grown on stiffer substrates. This is likely to have implications for proliferation of cancer cells within PDAC tumours, which are mechanically extremely stiff. This project will investigate the role of Ect2 mechano-sensing in pancreatic cancer cells and patient tumours. Specifically, this project aims to: 1. Characterise the effect of Ect2 depletion on PDAC cell proliferation, division and migration 2. Understand how mechanosensitive signalling regulates Ect2 localisation and activity 3. Image the localisation of Ect2 in PDAC patient tumours The project will use a combination of cell and molecular biology approaches (including CRISPR gene editing, western blotting, flow cytometry), advanced microscopy (live cell imaging & immunofluorescence) and histopathological staining of patient samples to elucidate the role of Ect2 in PDAC. To investigate the mechano-regulation of Ect2, cells will be grown on soft and stiff hydrogels to mimic the increasing tissue rigidity within PDAC tumours. Ultimately, this project aims to develop Ect2 as a potential new target for PDAC therapy. Lab website: https://www.helenmatthewslab.org/ Please apply for this project using this link: https://www.sheffield.ac.uk/postgraduate/phd/apply/applying Funding Notes Externally or self-funded students only Apply Now