[Regulation by Ca2+-calmodulin-dependent phosphorylation of passive transport of Ca2+ in the myometrial sarcolemma].
Closed vesiculate preparations of pig myometrium sarcolemma (predominantly with inside-out orientation) are characterized by passive permeability for Ca2+. The kinetics of Ca2+ release from the vesicles is exponential. Using the grapho-analytical subtraction method, the kinetic parameters of this reaction were determined. Myometrium sarcolemma contains endogenous Ca2+-calmodulin-dependent protein kinase and phosphoprotein phosphatase which is inhibited by sodium o-vanadate. The Ca2+-calmodulin-dependent phosphorylation stimulates passive Ca2+ release from sarcolemmal vesicles. In the course of phosphorylation the capacity of the pool providing for rapid Ca2+ release increases by 61%, the initial rate of Ca2+ release showing a 28% increase. Trifluoroperazine, an inhibitor of Ca2+-calmodulin-dependent processes, eliminates the activating effect of phosphorylation on the rate of Ca2+ release from sarcolemmal vesicles.
Kondratiuk
T P
TP
Prishchepa
L A
LA
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D005260:Female; D007700:Kinetics; D009215:Myometrium / Q000201:enzymology / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D012508:Sarcolemma / Q000201:enzymology / Q000378:metabolism*; D013552:Swine
D002147:Calmodulin; D011493:Protein Kinase C; D010727:Phosphoric Diester Hydrolases; D002118:Calcium
Reguliatsiia Ca2+-kal'modulinzavisimym fosforilirovanniem passivnogo transporta Ca2+ v sarkolemme miometriia.