The project aims to understand the mechanisms that regulate Ca2+ inside neural cells. Ca2+ fulfills an essential role in neural cells, controlling key excitatory responses including release of neurotransmitters, axonal membrane conductance, generation of action potentials, electrical coupling between neurons, and fast axonal transport. The proposed studies involve a combination of cell biological and biochemical approaches to analyze the molecular basis of mechanisms which control Ca2+ release into the neuronal cytoplasm and transfer Ca2+ inside neural cells. The project centers on Ca2+ transport mechanisms activated either by inositol phosphates or quanine nucleotides. The studies have three objectives: (1) Elucidation of the identity and organization of intracellular Ca2+ pools: studies will assess the function of Ca2+ regulatory organelles in clonal neuroblastoma cell cultures and isolated synaptosomes, identify at the subcellular level those organelles responsive to inositol 1,4,5-trisphophate (InsP3) and GTP, and use electron microscopy and electron probe microanalysis to localize intracellular Ca2+ pools within the neural systems. (2) Determination of the mechanisms of intracellular Ca2+ transport activated by InsP3 and GTP; measurements will be made on the nature and specificity of ion transport activated by InsP3, and on the physical and biochemical basis of the process by which a GTP-regulated mechanism mediates the translocation of Ca2+ between distinct Ca2+-regulatory compartments within neuronal cells. (3) Molecular characterization of the Ca2+ translocation mechanisms; studies are designed to identify the proteins involved in InsP3- and GTP-activated Ca2+ translocation, and to apply immunochemical approaches to the determinations of the existence of known Ca2+ - regulatory proteins within discrete membrane subfractions of neural cells. The project utilizes a combination of isotopic transport measurements, electron microscopic structural analyses, biophysical measurements on the interactions between membranes, protein analytical and immunochemical approaches, aa directed at ascertaining how Ca2+ translocation occurs within neural cells and what regulates it. In view of the fundamental role of Ca2+ in controlling neural functional, identification and characterization of the mechanisms that mediate and regulate Ca2+ signals in neural cells will permit understanding of the generation of neural excitability, and the development of methods to control the deleterious effects of diseases that alter neuronal conduction and excitability.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Project (R01)
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Physiology Study Section (PHY)
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University of Maryland Baltimore
Schools of Medicine
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Graber, M N; Alfonso, A; Gill, D L (1996) Ca2+ pools and cell growth: arachidonic acid induces recovery of cells growth-arrested by Ca2+ pool depletion. J Biol Chem 271:883-8
Gill, D L; Waldron, R T; Rys-Sikora, K E et al. (1996) Calcium pools, calcium entry, and cell growth. Biosci Rep 16:139-57
Ufret-Vincenty, C A; Short, A D; Alfonso, A et al. (1995) A novel Ca2+ entry mechanism is turned on during growth arrest induced by Ca2+ pool depletion. J Biol Chem 270:26790-3
Waldron, R T; Short, A D; Gill, D L (1995) Thapsigargin-resistant intracellular calcium pumps. Role in calcium pool function and growth of thapsigargin-resistant cells. J Biol Chem 270:11955-61
Ghosh, T K; Bian, J; Gill, D L (1994) Sphingosine 1-phosphate generated in the endoplasmic reticulum membrane activates release of stored calcium. J Biol Chem 269:22628-35
Waldron, R T; Short, A D; Meadows, J J et al. (1994) Endoplasmic reticulum calcium pump expression and control of cell growth. J Biol Chem 269:11927-33
Rys-Sikora, K E; Ghosh, T K; Gill, D L (1994) Modification of GTP-activated calcium translocation by fatty acyl-CoA esters. Evidence for a GTP-induced prefusion event. J Biol Chem 269:31607-13
Short, A D; Klein, M G; Schneider, M F et al. (1993) Inositol 1,4,5-trisphosphate-mediated quantal Ca2+ release measured by high resolution imaging of Ca2+ within organelles. J Biol Chem 268:25887-93
Short, A D; Bian, J; Ghosh, T K et al. (1993) Intracellular Ca2+ pool content is linked to control of cell growth. Proc Natl Acad Sci U S A 90:4986-90
Bian, J H; Ghosh, T K; Wang, J C et al. (1991) Identification of intracellular calcium pools. Selective modification by thapsigargin. J Biol Chem 266:8801-6

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