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A Two‐Dimensional Electrophoresis Study of Phosphorylation and Dephosphorylation of Chromaffin Cell Proteins in Response to a Secretory Stimulus
Author(s) -
Gutierrez Luis M.,
Ballesta Juan J.,
Hidalgo Maria J.,
Gandia Luis,
García Antonio G.,
Reig Juan A.
Publication year - 1988
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 - 10.1111/j.1471-4159.1988.tb03063.x
Subject(s) - dephosphorylation , phosphorylation , chromaffin cell , polyacrylamide gel electrophoresis , isoelectric point , activator (genetics) , stimulation , gel electrophoresis , biology , protein phosphorylation , database , chemistry , biochemistry , protein kinase a , phosphatase , neuroscience , gene , adrenal medulla , enzyme , computer science , catecholamine
Phosphorylated proteins of bovine chromaffin cells, radioactively labeled with [ 32 P]orthophosphate, have been analyzed by two‐dimensional polyacrylamide gel electrophoresis and autoradiography. Complex two‐dimensional electrophoretograms were studied with the aid of computer‐assisted image analysis (CAIA). A database map of 32 P‐labeled proteins was constructed; ∼500 polypeptides have been detected, numbered, and characterized according to the intensity of labeling, molecular weight, and iso‐electric point. The database was constructed from cells kept in resting conditions or stimulated with 59 m M K + in 2.5 m M Ca 2+ or in 0 Ca 2+ solution. These manipulations caused statistically significant changes in the degree of phosphorylation of 20 proteins; they were classified as Ca 2+ ‐dependent substrates for the phosphorylation or dephosphorylation processes. These changes were also shown in cells stimulated in the presence of the Ca 2+ channel activator Bay K 8644. New proteins that show as much as a fivefold increase in their phosphorylation state during cell stimulation have been located with this methodology, as well as many others that had not previously been detected with conventional methods. These experiments provide the first CAIA database of chromaffin cell phosphoproteins; the map constructed with these data will allow the location of specific phosphoproteins and serve as a reference for future ongoing studies. The database will continue to grow to identify more proteins and to facilitate the comparison of complex patterns obtained in different laboratories for normal and transformed pheochromocytoma PC 12 ceils.