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The Addition of Glucose‐1‐Phosphate to the Cytoplasmic Glycoprotein Phosphoglucomutase Is Modulated by Intracellular Calcium in PC12 Cells and Rat Cortical Synaptosomes
Author(s) -
Veyncy A.,
Jay Jeanne C.,
Srisomsap Chantragan,
Bounelis Pam,
Marchase Richard B.
Publication year - 1994
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.1994.62020456.x
Subject(s) - phosphoglucomutase , calcium , intracellular , chemistry , cytoplasm , calcium in biology , biochemistry , synaptosome , glycoprotein , microbiology and biotechnology , biophysics , biology , enzyme , organic chemistry
In a number of different cell types, phosphorylation of a 63‐kDa protein has been shown to increase rapidly in response to stimuli that lead to an increase in intracellular calcium. Here, a stimulus‐sensitive protein at this molecular weight is identified in PC12 cells and rat cortical synaptosomes as phosphoglucomutase. In addition, the added phosphate is shown to be in an oligosaccharide terminating in phosphodiester‐linked glucose. In synaptosomes, incorporated radioactivity, following incubation with [ 14 C]glucose or the [β‐ 35 S]phosphorothioate analogue of UDP‐glucose, was found to increase within 5 s of stimulation and return to baseline within 25 s. Despite the many pathways utilizing glucose, this was the only detectable protein glycosylation observed in synaptosomes. These results indicate that cytoplasmic glycosylation is reversible and rapidly regulated, and suggest that phosphoglucomutase undergoes an alteration in function and/or topography in response to increases in intracellular calcium.