title: MAPK mediates PKC-dependent contraction of cat esophageal and lower esophageal sphincter circular smooth muscle.
abstract: Esophageal (ESO) circular muscle contraction and lower esophageal sphincter (LES) tone are PKC dependent. Because MAPKs may be involved in PKC-dependent contraction, we examined ERK1/ERK2 and p38 MAPKs in ESO and LES. In permeabilized LES muscle cells, ERK1/2 antibodies reduced 1,2-dioctanoylglycerol (DG)- and threshold ACh-induced contraction, which are PKC dependent, but not maximal ACh, which is calmodulin dependent. LES tone was reduced by the ERK1/2 kinase inhibitor PD-98059 and by the p38 MAPK inhibitor SB-203580. In permeable ESO cells, ACh contraction was reduced by ERK1/ERK2 and p38 MAPK antibodies and by PD-98059 and SB-203580. ACh increased MAPK activity and phosphorylation of MAPK and of p38 MAPK. The 27-kDa heat shock protein (HSP27) antibodies reduced ACh contraction. HSP27 and p38 MAPK antibodies together caused no greater inhibition than either one alone. p38 MAPK and HSP27 coprecipitated after ACh stimulation, suggesting that HSP27 is linked to p38 MAPK. These data suggest that PKC-dependent contraction in ESO and LES is mediated by the following two distinct MAPK pathways: ERK1/2 and HSP27-linked p38 MAPK.
authors.affiliation: Department of Medicine, Rhode Island Hospital and Brown University, 593 Eddy Street, Providence, RI 02903, USA.
authors.forename: Weibiao
authors.initials: W
authors.lastname: Cao
authors.forename: Uy Dong
authors.initials: UD
authors.lastname: Sohn
authors.forename: Khalil N
authors.initials: KN
authors.lastname: Bitar
authors.forename: Jose
authors.initials: J
authors.lastname: Behar
authors.forename: Piero
authors.initials: P
authors.lastname: Biancani
authors.forename: Karen M
authors.initials: KM
authors.lastname: Harnett
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D002415:Cats; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004943:Esophagogastric Junction / Q000201:enzymology*; D004947:Esophagus / Q000201:enzymology*; D005419:Flavonoids / Q000494:pharmacology; D007093:Imidazoles / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000502:physiology*; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000201:enzymology*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D015290:Second Messenger Systems / Q000502:physiology; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2
chemical_list: D000109:Acetylcholine; D004791:Enzyme Inhibitors; D005419:Flavonoids; D007093:Imidazoles; D047908:Intracellular Signaling Peptides and Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011725:Pyridines; D048051:p38 Mitogen-Activated Protein Kinases; D000099190:MAP-Kinase-Activated Kinase 2; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one