TY - JOUR
T1 - Reconstitution of resolved muscarinic cholinergic receptors with purified GTP-binding proteins
AU - Florio, V. A.
AU - Sternweis, P. C.
N1 - Copyright:
Copyright 2004 Elsevier B.V., All rights reserved.
PY - 1985
Y1 - 1985
N2 - The association of agonists with muscarinic receptors in membranes from bovine brain was affected only slightly by guanine nucleotides. However, solubilization of these membranes with deoxycholate and subsequent removal of detergent resulted in a preparation of receptors with increased affinity for agonists and a large increase in response to guanine nucleotides. Chromatography of deoxycholate extracts of membranes on DEAE-Sephacel resulted in the separation of receptors from 95% of the guanine nucleotide-binding activity. Guanine nucleotides had no effect on the binding of agonists to these resolved receptors. The effect of guanine nucleotides was restored after the addition of either of two purified guanine nucleotide-binding proteins from bovine brain. One of these proteins, presumably brain G(I), is composed of subunits with the same molecular weights (α, 41,000; β, 35,000; γ, 11,000) and functions as the inhibitory guanine nucleotide-binding protein isolated from liver. The other protein, termed G(O), is a novel guanine nucleotide-binding protein that possesses a similar subunit composition (α, 39,000; β, 35,000; γ, 11,000) but whose function is not yet known. Addition of either protein to the resolved receptor preparation increased agonist affinity by at least 10-20-fold, and low concentrations of guanine nucleotides specifically reversed this effect. Reconstitution of receptors with the resolved subunits of G(O) demonstrates that the β-subunit alone had no effect on agonist binding, but that this subunit does appear to enhance the effects observed with the α subunit alone.
AB - The association of agonists with muscarinic receptors in membranes from bovine brain was affected only slightly by guanine nucleotides. However, solubilization of these membranes with deoxycholate and subsequent removal of detergent resulted in a preparation of receptors with increased affinity for agonists and a large increase in response to guanine nucleotides. Chromatography of deoxycholate extracts of membranes on DEAE-Sephacel resulted in the separation of receptors from 95% of the guanine nucleotide-binding activity. Guanine nucleotides had no effect on the binding of agonists to these resolved receptors. The effect of guanine nucleotides was restored after the addition of either of two purified guanine nucleotide-binding proteins from bovine brain. One of these proteins, presumably brain G(I), is composed of subunits with the same molecular weights (α, 41,000; β, 35,000; γ, 11,000) and functions as the inhibitory guanine nucleotide-binding protein isolated from liver. The other protein, termed G(O), is a novel guanine nucleotide-binding protein that possesses a similar subunit composition (α, 39,000; β, 35,000; γ, 11,000) but whose function is not yet known. Addition of either protein to the resolved receptor preparation increased agonist affinity by at least 10-20-fold, and low concentrations of guanine nucleotides specifically reversed this effect. Reconstitution of receptors with the resolved subunits of G(O) demonstrates that the β-subunit alone had no effect on agonist binding, but that this subunit does appear to enhance the effects observed with the α subunit alone.
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M3 - Article
C2 - 3919024
AN - SCOPUS:0022002472
SN - 0021-9258
VL - 260
SP - 3477
EP - 3483
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 6
ER -