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Title: Investigating nutrient-sensing mechanisms using high-throughput approaches
Author: Cobley, David
ISNI:       0000 0004 7657 3809
Awarding Body: University of Manchester
Current Institution: University of Manchester
Date of Award: 2014
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Cells are regularly faced with fluctuations in nutrient availability. The ability to sense nutrients and couple availability to the tight regulation of anabolic and catabolic processes is crucial for cell survival. Furthermore, the control of cell growth and the cell cycle are highly coordinated, allowing cells to control cell size. A key regulator in this process is Target of Rapamycin (TOR), which exists in two major complexes, TORC1 and TORC2. Whilst much is known about key effectors (downstream processes) of TOR, knowledge of how cells sense and relay information about nutrient availability to TOR remains limited. In fission yeast, nutrient availability can be manipulated to produce changes in cell cycle progression. Complete starvation results in the exit of cells from the cycle whilst a less severe starvation (termed nutrient stress) causes a reduction in cell size. These processes were exploited to explore the mechanisms behind nutrient- sensing in fission yeast. This study utilizes two main approaches; a genetic screen and phosphoproteomics screens to further investigate the nutrient-sensing mechanisms present in fission yeast. The genetic screen described here has produced a candidate (a phosphatidylinositol 3-phosphate 5-kinase, Ste12- W1037STOP) that is deficient in the ability to produce a phosphatidylinositol compound that may be required for the proper localization of the main nutrient- sensing complex, TORC1. The second approach, a phosphoproteomics screen, has identified a number of potential upstream and downstream targets of TOR signalling. Subsequent bioinformatics analyses have validated these sites through comparison of these novel targets with existing players present in the literature. More in-depth phosphorylation motif analyses have implicated a number of kinases (including Casein Kinase II) in the nutrient-sensing response. Additional analyses have implicated a novel phosphorylation site on Byr1 (a component of the fission yeast mating pathway) in the control of MAPK activity during mating. potential novel regulators and effectors of TOR signalling and will also form the basis for future studies.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available