p38 mitogen-activated protein kinase expression and activation in smooth muscle.
There is relatively little known about expression and activation of p38 mitogen-activated protein kinases (MAPKs) through G protein-linked, seven-transmembrane-spanning (STM) receptors in mammalian smooth muscle. To investigate the role of p38 MAPK in smooth muscle, we cloned and sequenced the p38 MAPK expressed in canine smooth muscles. A full-length clone of the canine p38 MAPK expressed in colonic smooth muscle was obtained by RT-PCR. The deduced amino acid sequence revealed 99% identity to the human p38 MAPK and differed from the human enzyme in only two conservative substitutions. The deduced molecular mass of the canine p38 MAPK is 41.2 kDa, with a calculated isoelectric point of 5.41. Canine p38 MAPK was found to be expressed in colonic, tracheal, and vascular smooth muscles and underwent increased tyrosine phosphorylation in response to motor neurotransmitters, acetylcholine (ACh) and neurokinin A (NKA), in colonic smooth muscle. There was an eightfold increase in p38 MAPK phosphorylation after a 10-min incubation with ACh and a threefold increase with NKA. We also identified a p38 immunoreactive kinase activity isolated from colonic smooth muscle homogenate by Mono Q chromatography. Partially purified p38 MAPK and activated recombinant p38 MAPK (Mpk2) phosphorylated both the known p38 MAPK substrate ATF2, as well as porcine stomach h-caldesmon in vitro. The results suggest that elements of the "stress-response" pathway may be coupled to transcriptional control as well as to cytoskeletal and possibly contractile protein phosphorylation in mammalian smooth muscle.
Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada 89557-0046, USA.
J C
JC
Hedges
I A
IA
Yamboliev
M
M
Ngo
B
B
Horowitz
L P
LP
Adam
W T
WT
Gerthoffer
D000109:Acetylcholine / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D018053:Arsenites / Q000494:pharmacology; D001483:Base Sequence; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism; D002478:Cells, Cultured; D003001:Cloning, Molecular; D003106:Colon / Q000166:cytology; D017931:DNA Primers; D004285:Dogs; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D008969:Molecular Sequence Data; D009130:Muscle, Smooth / Q000166:cytology / Q000201:enzymology*; D009131:Muscle, Smooth, Vascular / Q000201:enzymology*; D015288:Neurokinin A / Q000494:pharmacology; D010766:Phosphorylation; D016133:Polymerase Chain Reaction; D011651:Pulmonary Artery; D011725:Pyridines / Q000494:pharmacology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D017670:Sodium Compounds / Q000494:pharmacology; D014132:Trachea; D048051:p38 Mitogen-Activated Protein Kinases
D018053:Arsenites; D002148:Calmodulin-Binding Proteins; D017931:DNA Primers; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011725:Pyridines; D017670:Sodium Compounds; C017947:sodium arsenite; D015288:Neurokinin A; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D000109:Acetylcholine; C090942:4-(4-fluorophenyl)-2-(4-hydroxyphenyl)-5-(4-pyridyl)imidazole