Metabolic Organization by the Caveolae and Cytoskeleton

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DESCRIPTION (provided by applicant): This project will examine the role of the cytoskeleton and the caveolae in the organization and regulation of metabolism. The metabolic pathways were elucidated decades ago using invasive techniques and thus provided an assumption that the cytoplasm was uniform and essentially behaved as a "bag of enzymes". With less invasive techniques with higher spatial resolution and sensitivity, cell signaling pathways have recently been studied and a very different paradigm has arisen that cytoarchitecture is important for localization of signaling proteins and small molecules and that the cytoarchitecture is a key regulatory component for cell signaling. The caveolae have recently received considerable attention for their role in the regulation of cell signaling, however, their role in cell metabolism has been only superficially investigated. Caveolae are a likely site of glycolytic pathway localization which allows for the production of energy near energy-consuming processes such as ion transport and are likely critical to the specificity of insulin signaling in a variety of tissues. The cytoskeleton has been known to localize glycolytic enzymes but the role of such localization in the functional organization of glycolytic metabolism is not known. Therefore, we hypothesize that the cytoskeleton and the caveolae are important in the organization and regulation of vascular smooth muscle (VSM) metabolism. The aim of this proposal is to determine the role of the cytoskeleton (actin and tubulin) and caveolae in the structuring of metabolism in VSM. The investigators will test the hypothesis that microtubules and the actin cytoskeleton function as a scaffolding for anchoring glycolytic enzymes within the cytoplasm (specific aim 1) and that the association of glycolytic enzymes with these structures is responsible for the organization/compartmentation of metabolism in VSM. The investigators will also test the hypothesis that glycolytic enzymes are specifically localized to caveolae while gluconeogenic enzymes are specifically localized to non-caveolar regions of the membrane (specific aim 3) and that these specific associations are responsible for the organization of metabolism in VSM (specific aim 4). These investigations are likely applicable to a wide variety of cell types and will provide a new understanding of the structural basis for the organization of metabolism in VSM cells and begin to unveil the functional consequences of the organization of metabolism such as the role of organized metabolism in the support of cell function.