Emily Smith
Bioanalytical, Fluorescence and Chemical Imaging
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Research Interests
We are developing fluorescence and vibrational imaging techniques that can be used to study biomolecular processes in cells and tissue. The clustering of cell membrane proteins, the interaction of cell membrane proteins with extracellular and cytosolic proteins, and the post-translational modification of proteins are studied. The aim of this work is to further the understanding of molecular interactions in vivo, to provide insight into how cellular processes are altered in certain disease states, and to develop methods for screening potential therapeutic compounds.
Protein-Protein Interactions. In vivo labeling techniques, such as the use of fluorescent proteins, enables the study of protein-protein interactions in living cells and tissue using fluorescence microscopy. Fluorescence resonance energy transfer is a distance-dependant fluorescent technique used to measure the interactions of proteins on a scale lower than the resolution of an optical microscope (below 200 nm). Fluorescence recovery after photobleaching is used to measure the diffusion of receptors within the membrane. We are using these techniques to study the aggregation of membrane proteins after exposure to UV light, and to study the clustering of a class of cell membrane proteins that contribute to cancer metastasis.
Post-translational Modification of Proteins. Fourier transform infrared (FTIR) and Raman microscopy, in contrast to vibrational spectroscopy, provides spatially correlated chemical composition data. These methods are suited to study covalent modifications of biological molecules within cells and tissue. The resolution of an FTIR microscope is on the order of the dimensions of a typical mammalian cell, enabling single cells to be probed and heterogeneous changes in protein, nucleic acid, or lipid content and composition to be studied. Vibrational microscopy is used to study post-translational modifications such as protein glycosylation in a hyperglycemic environment and protein phosphorylation after exposure to UV radiation. These modifications affect the chemical and physical properties of the protein, and it is important to identify these modifications to understand how the protein functions.
