Analysis of Rho GTPase signalling pathways regulating epithelial morphogenesis.
Doctoral thesis, UCL (University College London).
Rho GTPases are molecular switches controlling many aspects of cell behaviour, including cell cycle progression, cell division, migration and morphology. The activity of Rho proteins is regulated by conformational changes induced by binding of guanine nucleotides, with GTP-bound Rho being active and GDP-bound Rho inactive. Families of regulatory proteins have evolved to catalyse cycling between these states. Guanine nucleotide exchange factors (GEFs) catalyse nucleotide exchange, allowing GDP to dissociate and GTP to bind to Rho, thus activating it. GTPase activating proteins (GAPs) enhance the intrinsic GTPase activity of Rho, leading to GTP hydrolysis and inactivation of Rho. Active GTP-bound Rho can interact with and regulate a number of effector proteins, through which cellular responses are elicited. Epithelial cells are a specialized cell type that form selectively permeable barriers between different compartments of a multicellular organism, and thus play an important role in tissue organization and homeostasis. The formation of cell-cell junctions, including tight junctions and adherens junctions, is critical for this function. Experiments carried out in model organisms and in cell culture have shown that Rho GTPases are important regulators of epithelial morphogenesis. I sought to identify components of the signalling pathways through which Rho GTPases regulate junction formation. RNAi screens were carried out with siRNA libraries targeting Rho GEFs, GAPs and effectors, using tight junction formation in the human bronchial epithelial cell line 16HBE as readout. This approach led to the identification of three Rho effector proteins required for junction formation, namely PRK2, PAK4 and PAR6B.
|Title:||Analysis of Rho GTPase signalling pathways regulating epithelial morphogenesis|
|Open access status:||An open access version is available from UCL Discovery|
|UCL classification:||UCL > School of Life and Medical Sciences > Faculty of Life Sciences > MRC/UCL Lab for Molecular Cell Biology|
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