Smooth muscles are essential for maintaining homeostasis in all chordate animals. In humans, aberrations in smooth muscle contractile responses have been implicated in hypertension, cardiovascular disease and asthma. Elucidation of the cellular and molecular basis of smooth muscle function is, therefore, crucial for the therapy of a number pathophysiological processes. It is now generally accepted that the phosphorylation of smooth muscle myosin by the Ca2+/calmodulin dependent enzyme myosin light chain kinase is a key regulatory event in the contractile process. However, a number of interesting observations suggest that this may not be the only regulatory mechanism and processes that do not involve myosin light chain kinase activation and/or myosin phosphorylation have been postulated. Therefore, the experiments described in this proposal are designed to obtain a detailed understanding of the role of myosin phosphorylation/dephosphorylation in regulating smooth muscles. Three experimental approaches that are continuations of ongoing research are planned. The thrust of the first series of experiments is to uncover alternative regulatory mechanisms by contracting muscles in the absence of an increase in cell Ca2+ or the activation of myosin light chain kinase. A second approach will be to introduce antibodies into intact living cells to deter- mine the localization of regulatory proteins. In these experiments the direct role of caldesmon, a putative regulatory protein, in regulating smooth muscle contraction will also be determined. The final series of experiments will address the regulation and physiological significance of fetal smooth muscle myosin. This series is based on the observation that protein kinase C, an enzyme implicated in a number of growth-related processes, phosphorylates and thereby activates fetal smooth muscle myosin while having an inhibitory effect on its adult counterpart. Thus, the proposed studies will increase our understanding of the role of myosin phosphorylation and clarify the presence of alternative mechanisms in regulating contractile processes in smooth muscles. This information will not only result in improved therapy for smooth muscle-associated diseases but may also help elucidate the strikingly similar contractile events that occur in non muscle cells.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL035808-07
Application #
3350148
Study Section
General Medicine B Study Section (GMB)
Project Start
1985-09-30
Project End
1993-11-30
Budget Start
1991-12-14
Budget End
1992-11-30
Support Year
7
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Illinois at Chicago
Department
Type
Schools of Medicine
DUNS #
121911077
City
Chicago
State
IL
Country
United States
Zip Code
60612
Gandhi, S; Lorimer, D D; de Lanerolle, P (1997) Expression of a mutant myosin light chain that cannot be phosphorylated increases paracellular permeability. Am J Physiol 272:F214-21
Tripuraneni, J; Koutsouris, A; Pestic, L et al. (1997) The toxin of diarrheic shellfish poisoning, okadaic acid, increases intestinal epithelial paracellular permeability. Gastroenterology 112:100-8
Christensen, S; Verhage, H G; Nowak, G et al. (1995) Smooth muscle myosin II and alpha smooth muscle actin expression in the baboon (Papio anubis) uterus is associated with glandular secretory activity and stromal cell transformation. Biol Reprod 53:598-608
de Lanerolle, P; Gorgas, G; Li, X et al. (1993) Myosin light chain phosphorylation does not increase during yeast phagocytosis by macrophages. J Biol Chem 268:16883-6
de Lanerolle, P (1992) Airway smooth muscle and asthma. Am J Respir Cell Mol Biol 7:565-6
Wilson, A K; Pollenz, R S; Chisholm, R L et al. (1992) The role of myosin I and II in cell motility. Cancer Metastasis Rev 11:79-91
Strauss, J D; de Lanerolle, P; Paul, R J (1992) Effects of myosin kinase inhibiting peptide on contractility and LC20 phosphorylation in skinned smooth muscle. Am J Physiol 262:C1437-45
de Lanerolle, P; Paul, R J (1991) Myosin phosphorylation/dephosphorylation and regulation of airway smooth muscle contractility. Am J Physiol 261:L1-14
Wilson, A K; Horwitz, J; De Lanerolle, P (1991) Evaluation of the electroinjection method for introducing proteins into living cells. Am J Physiol 260:C355-63
De Lanerolle, P; Strauss, J D; Felsen, R et al. (1991) Effects of antibodies to myosin light chain kinase on contractility and myosin phosphorylation in chemically permeabilized smooth muscle. Circ Res 68:457-65

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