Interactions between proteins involved in cell spreading and migration.
Department name: Department of Biochemistry, University of Cambridge
Supervisor: Dr Helen Mott
Our lab works on small G proteins of the Ras superfamily and their effector proteins. One effector for the Ras related G protein Ral is RLIP76 (or RalBP1). RLIP76 has been shown to also bind R-Ras (a G protein) and ARNO (an exchange factor). These interactions are necessary for R-Ras-mediated cell spreading and cell migration, which are important in cancer. This project aims to understand the molecular basis for these interactions, using biophysical methods, NMR and X-ray crystallography as appropriate. We have already solved structures of two domains within RLIP76 but these do not bind tightly to ARNO or R-Ras. We will generate larger fragments of the RLIP76 protein to delineate the binding sites for ARNO and R-Ras for structural studies. R-Ras is a lipid-modified peripheral membrane protein, so we will use modified R-Ras and membrane mimics to probe the role of the membrane in these interactions. RLIP76 is extensively phosphorylated in vivo and we will assess the role of phosphorylation in the interaction. Once the best binding conditions have been established we will solve the structures of binary and/or ternary complexes. This will allow the generation of RLIP76 mutants that selectively prevent binding to either ARNO or R-Ras: such mutants can be used in functional assays. We will also investigate the effects of ARNO and R-Ras binding on the ability of RLIP76 to behave as a GTPase activating protein for Rho family G proteins. Taken together, these structural and biochemical analyses will further our understanding of the role of RLIP76 and small G proteins in cell migration and help in the design of therapeutics to inhibit their function.
UK nationals and EU students who meet the residency requirements can apply via the MRC or the BBSRC DTP. Further information about eligibility for funding can be found on the BBSRC website:
H.R. Mott & D. Owen (2015) Structures of Ras superfamily effector complexes: What have we learnt in two decades? Crit Rev Biochem Mol Biol. 50 85-133.
S.Guin & D. Theodorescu (2015) The RAS-RAL axis in cancer: evidence for mutation specific selectivity in non-small cell lung cancer. Acta Pharmacologica Sinica. 36 291-297
Wurtzel et al (2015) RLIP76 regulates Arf6-dependent cell spreading and migration by linking ARNO with activated R-Ras at recycling endosomes BBRC 467 785-91
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FTE Category A staff submitted: 189.63
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