The goal is to determine the molecular mechanism of insulin action. Specific emphasis of this proposal is placed upon the roles that Ca2+ and the intracellular Ca2+ effector protein, calmodulin, play in 1) the initial coupling events that occur when insulin binds to its receptor, 2) the relationship of these events to the regulation of other Ca2+ homeostatic events in the plasma membrane, 3) their relationship to insulin stimulated glucose and amino acid transport and 4) the mechanism and metabolic significance of insulin's ability to stimulate Ca2+ transport by endoplasmic reticulum.
The specific aims of these investigations include: 1. Characterization of the functional and molecular relationships between the insulin-sensitive (Ca2+ + Mg2+)-ATPase, calmodulin and the insulin receptor in the adipocyte plasma membrane. 2. Characterization of other Ca2+ homeostatic events (Na+/Ca2+ exchange and Ca2+ channels) and Ca2+-related ion channels (Ca2+ dependent K+ channels and Ca2+/H+ and Na+/H+ exchange) in adipocyte plasma membranes and determine their relationship to insulin action. 3. Determination of the relationship between Ca2+/calmodulin and insulin action in the regulation of glucose transport and ADP ribosylation. 4. Determination of the mechanism and metabolic significance of insulin in the regulation of Ca2+ transport by adipocyte endoplasmic reticulum. These combined molecular and functional investigations are designed to clearly define the role of Ca2+ and calmodulin in insulin action, and should have considerable overall impact on unravelling the cellular mechanisms responsible for the action of this hormone.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK025897-10
Application #
3227666
Study Section
Metabolism Study Section (MET)
Project Start
1979-06-01
Project End
1991-08-31
Budget Start
1988-09-01
Budget End
1989-08-31
Support Year
10
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Washington University
Department
Type
Schools of Medicine
DUNS #
062761671
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Williams, J P; Jo, H; Hunnicutt, R E et al. (1995) Tyrosine phosphorylation of phosphatase inhibitor 2. J Cell Biochem 57:415-22
Hardy, R W; McDonald, J M; Remsen, E E et al. (1994) The interaction of calmodulin and polylysine as studied by 1H NMR spectroscopy and sedimentation equilibrium centrifugation. Biochem Biophys Res Commun 198:309-17
Hunnicutt, J W; Hardy, R W; Williford, J et al. (1994) Saturated fatty acid-induced insulin resistance in rat adipocytes. Diabetes 43:540-5
Williams, J P; Jo, H; Sacks, D B et al. (1994) Tyrosine-phosphorylated calmodulin has reduced biological activity. Arch Biochem Biophys 315:119-26
Jo, H; Radding, W; Anantharamaiah, G M et al. (1993) An insulin receptor peptide (1135-1156) stimulates guanosine 5'-[gamma-thio]triphosphate binding to the 67 kDa G-protein associated with the insulin receptor. Biochem J 294 ( Pt 1):19-24
Jo, H; Byer, S; McDonald, J M (1993) Insulin stimulates association of a 41kDa G-protein (GIR41) with the insulin receptor. Biochem Biophys Res Commun 196:99-106
Sacks, D B; Davis, H W; Crimmins, D L et al. (1992) Casein kinase II-catalysed phosphorylation of calmodulin is altered by amino acid deletions in the central helix of calmodulin. Biochem Biophys Res Commun 188:754-9
Hardy, R W; Ladenson, J H; Hruska, K A et al. (1992) The effects of extracellular calcium and epinephrine on cytosolic-free calcium in single rat adipocytes. Endocrinology 130:3694-702
Jo, H; Cha, B Y; Davis, H W et al. (1992) Identification, partial purification, and characterization of two guanosine triphosphate-binding proteins associated with insulin receptors. Endocrinology 131:2855-62
Sacks, D B; Davis, H W; Williams, J P et al. (1992) Phosphorylation by casein kinase II alters the biological activity of calmodulin. Biochem J 283 ( Pt 1):21-4

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