Photoaffinity labeling of turkey erythrocyte beta-adrenergic receptors: Degradation of the Mr = 49,000 protein explains apparent heterogeneity

Sibley, David R.; Peters, J R; Nambi, Ponnal; Caron, Marc G.; Lefkowitz, Robert J.

doi:10.1016/s0006-291x(84)80271-5

Cited by 16 publications

(2 citation statements)

References 13 publications

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“…Fur-thermore, when binding is also performed in the presence of the potent inhibitor of proteolysis phenylmethanesulphonyl fluoride (results not shown), no modification of the pattern of labelling is observed. These observations contrast markedly with other systems such as, for example, the ,Badrenergic receptors of turkey erythrocytes, where the ratio of photolabelling of the intact receptor and its degradation product are found to be very dependent on the method of tissue preparation and the presence of proteolysis inhibitors (Benovic et al, 1983;Sibley et al, 1984). The second hypothesis, i.e.…”

Section: Discussioncontrasting

confidence: 63%

The rat liver vasoactive intestinal peptide binding site. Molecular characterization by covalent cross-linking and evidence for differences from the intestinal receptor

Couvineau¹,

Laburthe²

1985

Biochemical Journal

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To identify the molecular components of the vasoactive intestinal peptide (VIP) binding sites in the liver, 125I-labelled VIP was covalently linked to liver membranes by using the cleavable cross-linker dithiobis(succinimidylpropionate). Purified rat liver plasma membranes were incubated with 125I-VIP, washed and treated with 1 mM-cross-linker. Polyacrylamide-gel electrophoresis of membrane proteins followed by autoradiography revealed a major 125I-VIP-protein complex of Mr 51 000. A minor Mr 89 000 complex was also observed. An identical pattern of protein labelling was obtained using crude membranes from rat liver. Labelling of the Mr 51 000 and 89 000 species was specific in that it could be abolished by native VIP, but was unaffected by 1 microM-glucagon and cholecystokinin octapeptide. Densitometric scanning of autoradiographs indicated that the labelling of the two species was abolished by similar low VIP concentrations (0.1-100 nM). It was also reduced by two VIP agonists, peptide histidine isoleucine amide and secretin, with a potency that is 1/7 and 1/200 that of native VIP, respectively. The guanine nucleotide GTP in the concentration range between 10(-7) and 10(-3) M reduces the labelling of the major Mr 51 000 protein and that of the minor Mr 89 000 protein, but with a slightly higher potency. Assuming one molecule of 125I-VIP was bound per molecule of protein, a major Mr 48 000 protein and a minor Mr 86 000 protein were identified as components of the high-affinity VIP binding sites in liver. This contrasts markedly with the pattern of labelling of rat intestinal epithelial membranes, where a Mr 73 000 protein was identified as a high-affinity VIP receptor and a Mr 33 000 protein as a low-affinity VIP binding site [Laburthe, Bréant & Rouyer-Fessard (1984) Eur. J. Biochem. 139, 181-187], suggesting structural differences between VIP binding sites in rat liver and intestinal epithelium.

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Section: Discussioncontrasting

confidence: 63%

The rat liver vasoactive intestinal peptide binding site. Molecular characterization by covalent cross-linking and evidence for differences from the intestinal receptor

Couvineau¹,

Laburthe²

1985

Biochemical Journal

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“…In other tissues, i.e., mammalian lung and cardiac membranes, endogenous proteases break down 8-receptor proteins to discrete lower molecular weight peptides (Benovic et al, 1982;Stiles et al, 1983) . In these cases, the proteases were inhibited by EDTA, phenylmethanesulfonyl fluoride, leupeptin, and pepstatin, whereas proteolysis of 8rrecePtors 'n turkey erythrocyte membranes is not susceptible to these inhibitors (Sibley et al, 1984) . This distinguishes the 8-receptor protease from other erythrocyte membrane proteases (Morrison & Neurath, 1953;Tokes & Chambers, 1975).…”

Section: Discussionmentioning

confidence: 93%

Proteolysis-associated deglycosylation of .beta.1-adrenergic receptor in turkey erythrocytes and membranes

Jürss¹,

Hekman²,

Helmreich³

1985

Biochemistry

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A protease that can be inhibited by glutathione, dithiothreitol, and o-phenanthroline but not by ethylenediaminetetraacetic acid converts the 50-kilodalton beta-adrenergic receptor in turkey erythrocyte membranes to a 40-kDa polypeptide which retains the specific ligand binding site. This conversion is attenuated in intact erythrocytes. The large 50-kDa peptide contains N-linked, complex carbohydrates and is retained on wheat germ agglutinin-Sepharose. The 40-kDa product of proteolysis does not bind to the wheat germ agglutinin and can thus be separated from the 50-kDa polypeptide by lectin chromatography. However, the large difference in molecular weights of the two receptor peptides cannot be accounted for solely by the different extent of glycosylation.

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β-Adrenergic Receptor-Coupled Adenylate Cyclase

Sibley

Lefkowitz

1988

Molecular Neurobiology

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Photoaffinity labeling of turkey erythrocyte beta-adrenergic receptors: Degradation of the Mr = 49,000 protein explains apparent heterogeneity

Cited by 16 publications

References 13 publications

The rat liver vasoactive intestinal peptide binding site. Molecular characterization by covalent cross-linking and evidence for differences from the intestinal receptor

The rat liver vasoactive intestinal peptide binding site. Molecular characterization by covalent cross-linking and evidence for differences from the intestinal receptor

Proteolysis-associated deglycosylation of .beta.1-adrenergic receptor in turkey erythrocytes and membranes

β-Adrenergic Receptor-Coupled Adenylate Cyclase

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