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Affinity‐Purified Anti‐B‐50 Protein Antibody: Interference with the Function of the Phosphoprotein B‐50 in Synaptic Plasma Membranes
Author(s) -
Oestreicher Anna Beate,
Dongen Carla J.,
Zwiers Henk,
Gispen Willem Hendrik
Publication year - 1983
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.1471-4159.1983.tb04747.x
Subject(s) - phosphatidylinositol , phosphoprotein , phosphorylation , biochemistry , affinity chromatography , membrane , membrane protein , phosphatidic acid , biology , chemistry , microbiology and biotechnology , phospholipid , enzyme
Affinity‐purified anti‐B‐50 protein antibodies were used to study the previously proposed relationship of the phosphorylation state of B‐50 protein and polyphosphoinositide metabolism in synaptic plasma membranes. Antibodies were raised against a membrane extract enriched in the B‐50 protein and its adrenocorticotropin‐sensitive protein kinase, obtained from rat brain. Anti‐B‐50 protein immunoglobulins were purified by affinity chromatography on a solid immunosorbent prepared from B‐50 protein isolated by an improved procedure. The purified antibodies reacted only with the B‐50 and B‐60 protein, a proteolysis derivative (of B‐50), as assessed by the sodium dodecyl sulfate‐gel immunoperoxidase method. These antibodies inhibited specifically the endogenous phosphorylation of B‐50 protein in synaptic plasma membranes, without affecting notably the phosphorylation of other membrane proteins. This inhibition was accompanied by changes of the formation of phosphatidylinositol 4,5‐diphosphate and phosphatidic acid in synaptic plasma membranes, whereas formation of phosphatidylinositol 4‐phosphate was not altered. Inhibition by ACTH 1–24 of the endogenous phosphorylation of B‐50 protein in membranes was associated only with an enhancement of the phosphorylation of phosphatidylinositol 4‐phosphate to phosphatidylinositol 4,5‐diphosphate. These data support our hypothesis on the functional interaction of B‐50 protein and phosphatidylinositol 4‐phosphate kinase in rat brain membranes. The evidence shows that purified anti‐B‐50 protein antibodies can be used to probe specifically the function of B‐50 protein in membranes.