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. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
3R01DK060668-03S1
Application #
7096494
Study Section
Metabolism Study Section (MET)
Program Officer
Haft, Carol R
Project Start
2003-04-01
Project End
2007-03-31
Budget Start
2005-04-01
Budget End
2006-03-31
Support Year
3
Fiscal Year
2005
Total Cost
$42,220
Indirect Cost
Name
University of Missouri-Columbia
Department
Pharmacology
Type
Schools of Medicine
DUNS #
153890272
City
Columbia
State
MO
Country
United States
Zip Code
65211
Mattern, H M; Hardin, C D (2007) Vascular metabolic dysfunction and lipotoxicity. Physiol Res 56:149-58
Hardin, Christopher D; Vallejo, Johana (2006) Caveolins in vascular smooth muscle: form organizing function. Cardiovasc Res 69:808-15
Raikar, Leena S; Vallejo, Johana; Lloyd, Pamela G et al. (2006) Overexpression of caveolin-1 results in increased plasma membrane targeting of glycolytic enzymes: the structural basis for a membrane associated metabolic compartment. J Cell Biochem 98:861-71
Vallejo, Johana; Hardin, Christopher D (2005) Expression of caveolin-1 in lymphocytes induces caveolae formation and recruitment of phosphofructokinase to the plasma membrane. FASEB J 19:586-7
Vallejo, Johana; Hardin, Christopher D (2004) Caveolin-1 functions as a scaffolding protein for phosphofructokinase in the metabolic organization of vascular smooth muscle. Biochemistry 43:16224-32
Vallejo, Johana; Hardin, Christopher D (2004) Metabolic organization in vascular smooth muscle: distribution and localization of caveolin-1 and phosphofructokinase. Am J Physiol Cell Physiol 286:C43-54