An Absolutely Conserved Motif of the Essential Translocon Subunit, Sss1, Dictates Protein Function and Stability with Implications for Personalised Medicine

ER channels and components in translocation are frequently described with roles in disease progression. We have characterised a highly conserved region of the essential translocon subunit, Sss1, which encodes the proteins degron and contributes to regulating translocon dynamics. This work has utilised these findings to design a yeast-based system to identify novel regulators of translocon dynamics, assess the impact translocon dynamics has in disease and may have future applications as part of drug discovery

The influence of exercise training on the profile of circulating metabolites and small extracellular vesicles, and the bioactivity of human plasma

Exercise factors are circulating signalling molecules that are responsive to acute exercise and exercise training. This thesis investigated (i) whether circulating metabolites, a source of exercise factors, change in response to short term exercise training, (ii) whether circulating metabolites and small extracellular vesicles (EVs; ‘carriers’ of exercise factors) are altered in an association with divergent histories of exercise training, and (iii) whether plasma extracted from men divergent exercise training histories influenced BT-549 cells. Nine sessions of sprint interval training reduced the abundance of 11 fatty acids in circulation in blood samples taken at rest. A history of exercise training was associated with alterations in the abundance of 44 of metabolites. Under standardized measurement conditions the reliability of plasma metabolite concentrations varied largely at the level of individual metabolites with ~48% of metabolites displaying good-to-excellent reliability. A history of exercise training was not associated with an altered abundance of small EVs across multiple methods of small EV identification. BT-549 cells cultured with media supplemented with plasma derived from men with divergent exercise training histories had increased cell proliferation, greater anoikis, and lower extracellular matrix invasion compared to standard cell-culture media conditions. This thesis provides insight into whether circulating metabolites are altered at rest in response to, or associated with, exercise training. This thesis does not support a paradigm wherein the ‘exercise factor environment’ at rest is largely different between healthy individuals with divergent training histories as assessed in terms of metabolite profile, small EV presence, or bioactive effects on BT-549 cells

Cellular determinants of metabolite concentration ranges.

Cellular functions are shaped by reaction networks whose dynamics are determined by the concentrations of underlying components. However, cellular mechanisms ensuring that a component's concentration resides in a given range remain elusive. We present network properties which suffice to identify components whose concentration ranges can be efficiently computed in mass-action metabolic networks. We show that the derived ranges are in excellent agreement with simulations from a detailed kinetic metabolic model of Escherichia coli. We demonstrate that the approach can be used with genome-scale metabolic models to arrive at predictions concordant with measurements from Escherichia coli under different growth scenarios. By application to 14 genome-scale metabolic models from diverse species, our approach specifies the cellular determinants of concentration ranges that can be effectively employed to make predictions for a variety of biotechnological and medical applications