This thesis focuses on the protein kinase N family of serine/threonine protein kinases. This comprises three isoforms, with kinase domains highly related to the protein kinase C family, but with distinctive Rho/Rac dependent regulation. The critical roles played by Rho/Rac in regulating the cytoskeleton and cell migration/invasion led to an investigation into the role of PKNs in this process. Initial work in the thesis derived from the observation that PKN1 translocated to an insoluble cytosolic compartment in response to hyperosmotic stress. This had been shown to be dependent upon Racl and 3-phosphoinositide dependent kinase (PDK1). The thesis describes the characterisation of the domain in PKN 1 responsible for the Rac-dependent hyperosmotic response. Through the use of PKNl/PKCzeta chimeras a 49 amino acid sequence within the kinase domain was shown to be necessary and sufficient for the observed osmotic behaviour. In developing a cell model for migration/invasion, a breast cancer cell model was identified that displayed high PKN expression. siRNA mediated depletion of PKN isoforms or inhibition of kinase activity, revealed a requirement for PKN in both migration and invasion. Comparison with other transformed cells indicated that the relative contribution each isoform makes towards these processes appears to be cell type dependent. As a candidate downstream target, PLD has been implicated in migration and invasion of breast cancer cells and so the previously described interaction between PKN and phospholipaseD in migrating breast cancer cells was investigated. Results suggest that the activity of PLD contributes to the migration of MDAMB-468 cells and that the production of phosphatidic acid in migrating cells is stimulated by PKN.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:500055 |
| Date | January 2008 |
| Creators | Jevons, Amy Louise |
| Publisher | University College London (University of London) |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://discovery.ucl.ac.uk/1444205/ |
Page generated in 0.0052 seconds