Role of 3'-phosphorylated phosphoinositides in neurosecretion. Neurons communicate through the release of neurotransmitter by synaptic vesicles. Minute changes underlie normal processes such as memory and modifications of neurotransmitter level contribute to a number of neurological diseases. I am interested in deciphering the role of phosphoinositides, an inner membrane-based lipid, during steps leading to the fusion of a synaptic vesicle with the plasma membrane. I have recently discovered tha ....Role of 3'-phosphorylated phosphoinositides in neurosecretion. Neurons communicate through the release of neurotransmitter by synaptic vesicles. Minute changes underlie normal processes such as memory and modifications of neurotransmitter level contribute to a number of neurological diseases. I am interested in deciphering the role of phosphoinositides, an inner membrane-based lipid, during steps leading to the fusion of a synaptic vesicle with the plasma membrane. I have recently discovered that phosphatidylinositol-3 phosphate production was critical for the vesicle to acquire the competence to fuse with the plasma membrane. This project aim to understand by which mechanism this lipid interacts with the release machinery to promote such priming step.Read moreRead less
Function and regulation of the Na+,K+-ATPase. The Na+,K+-ATPase is the major energy-consuming enzyme of animal cells. Its ion pumping is essential for numerous physiological functions (e.g. heart, kidney, brain). Molecular detail of its pumping mechanism is, however, lacking and its regulation is still unclear. We will use rapid reaction methods on purified enzyme in vitro to locate the rate-determining step of the enzyme cycle, determine its mechanism, investigate its regulation by sodium conce ....Function and regulation of the Na+,K+-ATPase. The Na+,K+-ATPase is the major energy-consuming enzyme of animal cells. Its ion pumping is essential for numerous physiological functions (e.g. heart, kidney, brain). Molecular detail of its pumping mechanism is, however, lacking and its regulation is still unclear. We will use rapid reaction methods on purified enzyme in vitro to locate the rate-determining step of the enzyme cycle, determine its mechanism, investigate its regulation by sodium concentration, phosphorylation and membrane composition, and isolate its charge-transporting steps. The results will have immediate impact on the understanding of the enzyme's mechanism, its metabolic control and its role in disease.Read moreRead less
Three-dimensional structures, substrate specificities and catalytic mechanisms of polysaccharide synthases. Plant wall polysaccharides are extensively used for food and fibre, and are important dietary components in human nutrition. A precise knowledge of mechanisms used by plants to synthesize these polysaccharides is unavailable, but would reveal potential routes to manipulate their biosynthesis in important crop species. For example, the levels or structures of polysaccharides might be modif ....Three-dimensional structures, substrate specificities and catalytic mechanisms of polysaccharide synthases. Plant wall polysaccharides are extensively used for food and fibre, and are important dietary components in human nutrition. A precise knowledge of mechanisms used by plants to synthesize these polysaccharides is unavailable, but would reveal potential routes to manipulate their biosynthesis in important crop species. For example, the levels or structures of polysaccharides might be modified to improve their efficacy as anti-cancer agents in human diets, to enhance digestibility of animal stock feeds, or to synthesise pharmologically valuable compounds. Thus, economic, social and environmental benefits will flow to both producers and consumers. Read moreRead less