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Ubiquitin‐Directed Antibodies Inhibit Neuronal Transporters in Rat Brain Synaptosomes
Author(s) -
Meyer Edwin M.,
M. West Christopher,
Stevens Bruce R.,
Chau Vincent,
Nguyen Minhthanh,
Judkins Jennifer H.
Publication year - 1987
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.1471-4159.1987.tb02441.x
Subject(s) - synaptosome , chemistry , sodium , biochemistry , glutamate receptor , transporter , membrane , receptor , organic chemistry , gene
Affinity‐purified antibodies specific for ubiquitin were found to inhibit the sodium‐dependent uptake of [ 3 H]choline, r‐[ 3 H]aminobutyric acid ([ 3 H]GABA), [ 3 H]‐glutamate, [ 3 H]norepinephrine, [ 3 H]aspartate, and [ 3 H]scrotonin in rat cerebral cortical synaptosomes at a low concentration (10 μg/ml). These antibodies (termed anti‐Uh) had no effect on the sodium‐independent uptake of these substances or their calcium‐dependent efflux. Synaptosomal [ 3 H]deoxyglucose uptake was not affected in normal Krebs Ringer buffer containing 10 m M glucose, but was inhibited in glucose‐free medium. Other nonneuronal sodium‐dependent transport processes were found to be unaffected by 10 μg/ml anti‐Ub, suggesting that anti‐Ub does not bind indiscriminantly to sodium‐binding sites on sodium‐dependent organic solute transporters. Finally, anti‐Ub inhibited sodium‐dependent [ 3 H]GABA and [ 3 H]glutamate uptake in plasma membrane ghosts, devoid of membrane potential, which were derived from rat cerebral cortical synaptosomes. These results suggest that neuronal transporters or sites proximal to them may be ubiquitinylated on the plasma membrane surface.