Scheme: Industry Fellowship
Organisation: Edinburgh Instruments Ltd
Dates: Oct 2007-Mar 2012
Summary: It is widely believed that signal transduction in cells is controlled by organisation of membrane proteins in dynamic molecular ensembles. Conventional biochemical and immunochemical methods cannot measure proximity of membrane expressed molecules. Fluorescence Resonance Energy Transfer can be used only in a limited number of cases as its resolution is limited to ca 10 nm. In majority of cases separating distances are significantly longer and therefore development of new methods with larger spatial resolution is in great demand. A novel method combining single photon counting, fluorescence confocal techniques and new advances in quantum dot tagging gives a unique choice of studying dynamic molecular complexes and on the surface of live cells. This method extends the resolution in signal transduction by more than one order of magnitude in molecular separation to ca 300nm. The method has the potential to determine stoichiometry of molecular ensembles on the cell surface and follow dynamics of their formation. This opens a new range of applications to study organisation of membrane expressed proteins and other molecular interactions. First application of this method to the central immunological problem sheds a new light on the mechanism of signalling in T cell lymphocytes. It is likely that the responsiveness of T cells is controlled by a fraction of proximal TCR and CD8 molecules and association of TCR in microclusters, which is in turn controlled by interactions of the immune receptor’s transmembrane domains with cholesterol enriched membrane domains. This finding can facilitate design of new vaccines against inflectional diseases and drugs for treatment of various immune disorders.