Skip to content
BY-NC-ND 3.0 license Open Access Published by De Gruyter June 2, 2014

Ca2+ Uptake Coupled to Glycogen Phosphorolysis in the Glycogenolytic-Sarcoplasmic Reticulum Complex from Rat Skeletal Muscle

  • M. Nogues , A. Cuenda , F. Henao and C. Gutiérrez-Merino

Abstract

The glycogenolytic-sarcoplasmic reticulum complex from rat skeletal muscle accumulates Ca2+ upon stimulation of glycogen phosphorolysis in the absence of added ATP. It is shown that an efficient Ca2+ uptake involves the sequential action of glycogen phosphorylase, phosphoglucomutase and hexokinase, which generate low concentrations of ATP (approximately 1 -2 μм) compartmentalized in the immediate vicinity of the sarcoplasmic reticulum Ca2+, Mg2+-ATPase (the Ca2+ pump). The Ca2+ uptake supported by glycogenolysis in this subcellular structure is strongly stimulated by micromolar concentrations of AMP, showing that the glycogen phosphorylase associated with this complex is in the dephosphorylated b form. The results point out that the flux through this compartmentalized metabolic pathway should be enhanced in physiological conditions leading to increased AMP concentrations in the sarcoplasm, such as long-lasting contractions and in ischemic muscle.

Received: 1996-1-9
Revised: 1996-2-28
Published Online: 2014-6-2
Published in Print: 1996-8-1

© 1946 – 2014: Verlag der Zeitschrift für Naturforschung

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Downloaded on 28.3.2024 from https://www.degruyter.com/document/doi/10.1515/znc-1996-7-819/html
Scroll to top button