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 re...

Full description

Saved in:

Bibliographic Details
Published in:	Biokhimiia (Moscow, Russia) Vol. 54; no. 8; p. 1368
Main Authors:	Kondratiuk, T P, Prishchepa, L A
Format:	Journal Article
Language:	Russian
Published:	Russia (Federation) 01-08-1989
Subjects:	Animals Biological Transport Calcium - metabolism Calmodulin - metabolism Female Kinetics Myometrium - enzymology Myometrium - metabolism Phosphoric Diester Hydrolases - metabolism Phosphorylation Protein Kinase C - metabolism Sarcolemma - enzymology Sarcolemma - metabolism Swine
Online Access:	Get more information
Tags:	Add Tag No Tags, Be the first to tag this record!

Description
Summary:	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.
ISSN:	0320-9725