Absence of calponin phosphorylation in contracting or resting arterial smooth muscle.
We have tested the hypothesis of Winder and Walsh [(1990) J. Biol. Chem. 265, 10148] that the contractile state of smooth muscle is regulated by calponin phosphorylation. Porcine carotid arterial muscles were highly labeled with 32P, then contracted with four different agents for various times. No radioactivity was detected in calponin isolated by 2D or 1D gel electrophoresis from the muscles. Similarly, resting muscles showed no [32P]phosphate in calponin. Apparently the sites of calponin available for phosphorylation in vitro are rendered unavailable in the intact muscle.
Bárány
M
M
Department of Biochemistry, College of Medicine, University of Illinois Chicago 60612.
Rokolya
A
A
Bárány
K
K
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002339:Carotid Arteries / Q000378:metabolism*; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D008840:Microfilament Proteins; D009119:Muscle Contraction; D009131:Muscle, Smooth, Vascular / Q000378:metabolism*; D010766:Phosphorylation; D013552:Swine; D000096985:Calponins
D002135:Calcium-Binding Proteins; D008840:Microfilament Proteins; D000096985:Calponins