SPEAKER: Prof. Ka Yee C. Lee (Professor, Department of Chemistry, The University of Chicago)
TITLE: Lipid-Protein Interactions at Membrane Surfaces: From a-Synuclein to Immunological Response
ABSTRACT: The cell membrane separates the interior of a cell from the exterior and is the front line for interactions with the cell’s environment. The talk will present strategies for interrogating two such interactions at membrane surfaces. The first involves alpha-Synuclein, an abundant protein found in the presynaptic terminal of neuronal axons and its dysfunction is fundamentally linked to Parkinson’s disease. While alpha-Synuclein is accepted to peripherally bind to the membrane of highly curved synaptic vesicles, there is increasing evidence that alpha-Synuclein can subsequently regulate the size and architecture of synaptic vesicle “pools” through an unknown mechanism. Here, we present strong evidence that alpha-Synuclein (at biologically relevant concentrations) disrupts inter-membrane interactions between synaptic vesicle-mimics at physiological salt and temperature conditions through a combination of synchrotron small-angle X-ray scattering (SAXS)and X-ray photon correlation spectroscopy (XPCS). The second examines lipid-protein interactions pertinent to immune response. The immune system recognizes a vast array of chemical signatures as antigens, although historically most research has focused almost exclusively on protein/protein recognition. More recently it has been appreciated that lipids can also be a potent stimulus. We have examined the differential recognition of a family of T-cell Immunoglobulin and Mucin domain (TIM) proteins; the molecular mechanisms by which this family of unique phosphatidylserine receptors can directly recognize “out of context” components of the lipid membrane gleaned from a combination of fluorescence spectroscopy, X-ray reflectivity and molecular dynamics simulation will be presented.
Meeting ID: 923 5279 5629
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