Abstract

Actomyosin ATPase activity of smooth muscle and non-muscle cells is regulated by at least two calcium-sensitive processes: (a) the interaction of caldesmon with actin filaments and (b) the phosphorylation of myosin light chains by specific kinases. Although much is already known about light chain phosphorylation, there is considerable disagreement on the role of caldesmon, particularly in non-muscle cells. The objectives of this proposal are to characterize the Ca2+-dependent regulation of adrenal medullary contractile proteins and to determine the significance of this regulation in light of the primary activity of medullary cells: catecholamine secretion by exocytosis. Experiments are designed to obtain the following information: (1) the rate of medullary myosin light chain phosphorylation, (2) the effect of phosphorylation on specific steps of the ATPase cycle, (3) the affinity of medullary caldesmon for calmodulin and for actin in the presence of Ca2+/calmodulin, (4) the effect of the actin-caldesmon interaction on ATPase activity, and (5) the relationship between myosin phosphorylation and catecholamine secretion in intact or permeabilized adrenal chromaffin cells. Results of these studies should increase understanding of the control of non-muscle cell motility and will advance progress toward the long-range goal of this research: the identification of specific steps of the secretory pathway in which cytoskeletal and contractile proteins are involved.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM038567-02
Application #
3295096
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1988-07-01
Project End
1991-06-30
Budget Start
1989-07-01
Budget End
1990-06-30
Support Year
2
Fiscal Year
1989
Total Cost
Indirect Cost

  Institution

Name
University of Texas Sw Medical Center Dallas
Department
Type
Schools of Medicine
DUNS #
City
Dallas
State
TX
Country
United States
Zip Code
75390

  Publications

Barylko, B; Binns, D D; Albanesi, J P (2001) Activation of dynamin GTPase activity by phosphoinositides and SH3 domain-containing proteins. Methods Enzymol 329:486-96
Lin, H C; Barylko, B; Achiriloaie, M et al. (1997) Phosphatidylinositol (4,5)-bisphosphate-dependent activation of dynamins I and II lacking the proline/arginine-rich domains. J Biol Chem 272:25999-6004
Earnest, S; Khokhlatchev, A; Albanesi, J P et al. (1996) Phosphorylation of dynamin by ERK2 inhibits the dynamin-microtubule interaction. FEBS Lett 396:62-6
Reizes, O; Barylko, B; Li, C et al. (1994) Domain structure of a mammalian myosin I beta. Proc Natl Acad Sci U S A 91:6349-53
Wagner, M C; Barylko, B; Albanesi, J P (1992) Tissue distribution and subcellular localization of mammalian myosin I. J Cell Biol 119:163-70
Barylko, B; Wagner, M C; Reizes, O et al. (1992) Purification and characterization of a mammalian myosin I. Proc Natl Acad Sci U S A 89:490-4
Yoo, S H; Albanesi, J P (1991) High capacity, low affinity Ca2+ binding of chromogranin A. Relationship between the pH-induced conformational change and Ca2+ binding property. J Biol Chem 266:7740-5
Hildebrandt, E; Albanesi, J P (1991) Identification of a membrane-bound, glycol-stimulated phospholipase A2 located in the secretory granules of the adrenal medulla. Biochemistry 30:464-72
Yoo, S H; Albanesi, J P; Jameson, D M (1990) Fluorescence studies of nucleotide interactions with bovine adrenal chromogranin A. Biochim Biophys Acta 1040:66-70
Yoo, S H; Albanesi, J P (1990) Inositol 1,4,5-trisphosphate-triggered Ca2+ release from bovine adrenal medullary secretory vesicles. J Biol Chem 265:13446-8

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