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Modulation by phosphorylation of glycogen phosphorylase‐sarcoplasmic reticulum interaction
Author(s) -
Cuenda Ana,
Centeno Francisco,
Gutierrez-Merino Carlos
Publication year - 1991
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(91)80606-4
Subject(s) - glycogen phosphorylase , endoplasmic reticulum , phosphorylation , chemistry , phosphorylase kinase , glycogen , modulation (music) , biophysics , sarcoplasm , microbiology and biotechnology , biochemistry , biology , physics , acoustics
Glycosen phosphorylase b at concentrations close to those found in skeletal muscle interacts with sarcoplasmic reticulum membranes, but not with liposomes made of lipids extracted from these membranes, and is inhibited upon binding to the membrane. The interaction of glycogen phosphorylase with the sarcoplasmic reticulum membrane is modulated by phosphorylation, for the a form of this enzyme shows a K 0.5 of interaction about 10‐fold lower than the b form. Upon association to the membrane the fluorescence properties of the coenzymes of glycogen phosphorylase, pyridoxal‐5′‐phosphate, are strongly altered, for the fluorescence at 535 nm is partially quenched and the fluorescence at 415–420 nm increases. Using fluorescein labeled sarcoplasmic reticulum membranes we have found that average conformation of the Ca 2+ + Mg 2+ ‐ATPaze is also altered on binding or phosphorylase b . In conclusion, the results reported in this paper suggest that glycogen phosphorylase and Ca 2+ + Mg 2+ ‐ATPase directly interact under experimental conditions similar to those found in the sarcoplasm, and that this interaction is modulated by phosphorylation of the phosphorylase.