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Title: Characterization of a bombesin receptor on Swiss mouse 3T3 cells by affinity cross-linking

Abstract

We have previously identified by chemical cross-linking a cell surface protein in Swiss 3T3 cells of apparent Mr 75,000-85,000, which may represent a major component of the receptor for peptides of the bombesin family in these cells. Because bombesin-like peptides may interact with other cell surface molecules, it was important to establish the correlation between receptor binding and functions of this complex and further characterize the Mr 75,000-85,000 cross-linked protein. Detailed time courses carried out at different temperatures demonstrated that the Mr 75,000-85,000 affinity-labelled band was the earliest cross-linked complex detected in Swiss 3T3 cells incubated with 125I-labelled gastrin-releasing peptide (125I-GRP). Furthermore, the ability of various nonradioactive bombesin agonists and antagonists to block the formation of the Mr 75,000-85,000 cross-linked complex correlated extremely well (r = 0.994) with the relative capacity of these peptides to inhibit 125I-GRP specific binding. Pretreatment with unlabelled GRP for up to 6 h caused only a slight decrease in both specific 125I-GRP binding and the affinity labelling of the Mr 75,000-85,000 protein. We also show that the cross-linked complex is a glycoprotein. First, solubilized affinity labelled Mr 75,000-85,000 complex applied to wheat germ lectin-sepharose columns was eluted by addition of 0.3 M N-acetyl-D-glucosamine. Second, treatmentmore » with endo-beta-N-acetylglucosaminidase F reduced the apparent molecular weight of the affinity-labelled band from 75,000-85,000 to 43,000, indicating the presence of N-linked oligosaccharide groups.« less

Authors:
; ;
Publication Date:
Research Org.:
Imperial Cancer Research Fund, London (England)
OSTI Identifier:
6101675
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Cell. Biochem.; (United States); Journal Volume: 38:4
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; PEPTIDES; RECEPTORS; BIOCHEMICAL REACTION KINETICS; AFFINITY; CELL CULTURES; CELL MEMBRANES; CROSS-LINKING; GLYCOPROTEINS; GLYCOSYL HYDROLASES; IODINE 125; MICE; MOLECULAR WEIGHT; TRACER TECHNIQUES; ANIMALS; BETA DECAY RADIOISOTOPES; CELL CONSTITUENTS; CHEMICAL REACTIONS; DAYS LIVING RADIOISOTOPES; ELECTRON CAPTURE RADIOISOTOPES; ENZYMES; HYDROLASES; INTERMEDIATE MASS NUCLEI; IODINE ISOTOPES; ISOTOPE APPLICATIONS; ISOTOPES; KINETICS; MAMMALS; MEMBRANE PROTEINS; MEMBRANES; NUCLEI; ODD-EVEN NUCLEI; ORGANIC COMPOUNDS; POLYMERIZATION; PROTEINS; RADIOISOTOPES; REACTION KINETICS; RODENTS; VERTEBRATES; 550201* - Biochemistry- Tracer Techniques

Citation Formats

Sinnett-Smith, J., Zachary, I., and Rozengurt, E.. Characterization of a bombesin receptor on Swiss mouse 3T3 cells by affinity cross-linking. United States: N. p., 1988. Web. doi:10.1002/jcb.240380403.
Sinnett-Smith, J., Zachary, I., & Rozengurt, E.. Characterization of a bombesin receptor on Swiss mouse 3T3 cells by affinity cross-linking. United States. doi:10.1002/jcb.240380403.
Sinnett-Smith, J., Zachary, I., and Rozengurt, E.. 1988. "Characterization of a bombesin receptor on Swiss mouse 3T3 cells by affinity cross-linking". United States. doi:10.1002/jcb.240380403.
@article{osti_6101675,
title = {Characterization of a bombesin receptor on Swiss mouse 3T3 cells by affinity cross-linking},
author = {Sinnett-Smith, J. and Zachary, I. and Rozengurt, E.},
abstractNote = {We have previously identified by chemical cross-linking a cell surface protein in Swiss 3T3 cells of apparent Mr 75,000-85,000, which may represent a major component of the receptor for peptides of the bombesin family in these cells. Because bombesin-like peptides may interact with other cell surface molecules, it was important to establish the correlation between receptor binding and functions of this complex and further characterize the Mr 75,000-85,000 cross-linked protein. Detailed time courses carried out at different temperatures demonstrated that the Mr 75,000-85,000 affinity-labelled band was the earliest cross-linked complex detected in Swiss 3T3 cells incubated with 125I-labelled gastrin-releasing peptide (125I-GRP). Furthermore, the ability of various nonradioactive bombesin agonists and antagonists to block the formation of the Mr 75,000-85,000 cross-linked complex correlated extremely well (r = 0.994) with the relative capacity of these peptides to inhibit 125I-GRP specific binding. Pretreatment with unlabelled GRP for up to 6 h caused only a slight decrease in both specific 125I-GRP binding and the affinity labelling of the Mr 75,000-85,000 protein. We also show that the cross-linked complex is a glycoprotein. First, solubilized affinity labelled Mr 75,000-85,000 complex applied to wheat germ lectin-sepharose columns was eluted by addition of 0.3 M N-acetyl-D-glucosamine. Second, treatment with endo-beta-N-acetylglucosaminidase F reduced the apparent molecular weight of the affinity-labelled band from 75,000-85,000 to 43,000, indicating the presence of N-linked oligosaccharide groups.},
doi = {10.1002/jcb.240380403},
journal = {J. Cell. Biochem.; (United States)},
number = ,
volume = 38:4,
place = {United States},
year = 1988,
month =
}
  • Bombesin (BN), gastrin-releasing peptide (GRP) and GRP(18-27) (neuromedin C) were equipotent and 30-fold more potent than neuromedin B (NMB) in inhibiting binding of {sup 125}I-GRP to and in stimulating amylase release from mouse pancreatic acini. In the present study we used {sup 125}I-GRP and chemical cross-linking techniques to characterize the mouse pancreatic BN receptor. After binding of {sup 125}I-GRP to membranes, and incubation with various chemical cross-linking agents, cross-linked radioactivity was analyzed by SDS-PAG electrophoresis and autoradiography. With each of 4 different chemical cross-linking agents, there was a single broad polypeptide band of Mr 80,000. Cross-linking did not occur inmore » the absence of the cross-linking agent. Cross-linking was inhibited only by peptides that interact with the BN receptor such as GRP, NMB, GRP(18-27) or BN. Dose-inhibition curves for the ability of BN or NMB to inhibit binding of {sup 125}I-GRP to membranes or cross-linking to the 80,000 polypeptide demonstrated for both that BN was 15-fold more potent than NMB. The apparent molecular weight of the cross-linked polypeptide was unchanged by adding dithiothreitol. N-Glycanase treatment reduced the molecular weight of the cross-linked peptide to 40,000. The present results indicate that the BN receptor on mouse pancreatic acinar cell membranes resembles that recently described on various tumor cells in being a single glycoprotein with a molecular weight of 76,000. Because dithiothreitol had no effect, this glycoprotein is not a subunit of a larger disulfide-linked structure.« less
  • The authors applied affinity cross-linking methods to label the gastrin receptor on isolated canine gastric parietal cells in order to elucidate the nature of its chemical structure. /sup 125/I-labeled Leu/sup 15/-gastrin and /sup 125/I-labeled gastrin/sub 2-17/ bound to intact parietal cells and their membranes with equal affinity, and half-maximal inhibition of binding was obtained at an incubation concentration of 3.2 x 10/sup -10/ M unlabeled gastrin. /sup 125/I-gastrin/sub 2-17/ was cross-linked to plasma membranes or intact parietal cells by incubation in disuccinimidyl suberate. The membrane pellets were solubilized with or without dithiothreitol and applied to electrophoresis on 7.5% sodium dodecylmore » sulfate polyacrylamide gels. Autoradiograms revealed a band of labeling at M/sub r/ 76,000 and labeling of this band was inhibited in a dose-dependent fashion by addition of unlabeled gastrin to the incubation mixture. Dithiothreitol in concentrations as high as 100 mM did not later the electrophoretic mobility of the labeled band. After taking into account the molecular weight of /sup 125/I-gastrin/sub 2-17/, the results suggest that the gastrin receptor on parietal cells is a single protein of M/sub r/ 74,000 without disulfide-linked subunits.« less
  • The bombesin receptor present on the surface of murine and human cells was identified using /sup 125/I-labeled gastrin-releasing peptide as a probe, the cross-linking agent disuccinimidyl suberate, and sodium dodecyl sulfate gels. A clone of NIH-3T3 cells which possesses approximately 80,000 bombesin receptors/cell with a single binding constant of approximately 1.9 X 10(-9) M was used in these studies. In addition, we used Swiss 3T3 cells and a human glioma cell line which possesses approximately 100,000 and approximately 55,000 bombesin receptors/cell, respectively. Under conditions found optimal for binding, it is demonstrated that /sup 125/I-labeled gastrin-releasing peptide can be cross-linked specificallymore » to a glycoprotein of apparent molecular mass of 65,000 daltons on the surface of the NIH-3T3 cells. Similar results were obtained when the cross-linked product was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing or non-reducing conditions. Moreover, the cross-linking reaction is specific and saturable and the 65,000-dalton polypeptide is not observed when the cross-linking experiments were performed with a NIH-3T3 cell line which is devoid of bombesin receptors. Interestingly, glycoproteins with apparent molecular weights of 75,000 were labeled specifically by /sup 125/I-labeled gastrin-releasing peptide when similar experiments were performed with Swiss 3T3 cells and with human glioma cell line GM-340. These different molecular weights may indicate differential glycosylation as treatment with the enzyme N-glycanase reduced the apparent molecular weight of the cross-linked polypeptide to 45,000. On the basis of these results it is concluded that the cross-linked polypeptides represent the bombesin receptor or the ligand-binding subunit of a putative larger bombesin receptor expressed on the surface of these cells.« less
  • Gastrin-releasing peptide (GRP) labeled with /sup 125/I at tyrosine-15 (/sup 125/I-GRP) binds to intact quiescent Swiss 3T3 cells in a specific and saturable manner. Scatchard analysis indicates the presence of a single class of high-affinity binding sites of Kd = 0.5 X 10(-9) M and a value for the number of sites per cell of about 100,000. /sup 125/I-GRP binding was not inhibited by other mitogens for these cells, and cell lines that are mitogenically unresponsive to GRP do not exhibit specific GRP binding. Structure-activity relationships show a close parallel between the ability of a range of GRP-related peptides tomore » both inhibit GRP binding and to stimulate mitogenesis. Further, GRP binding is selectively blocked in a competitive fashion by a novel bombesin antagonist, (D-Arg1, D-Pro2, D-Trp7,9, Leu11) substance P. In addition, this compound selectively inhibits GRP and bombesin-induced mitogenesis. These results demonstrate that the mitogenic response of Swiss 3T3 cells to peptides of the bombesin family is mediated by a class of receptors distinct from those of other mitogens for these cells.« less
  • Addition of the mitogenic peptides bombesin and vasopressin to quiescent Swiss 3T3 mouse cells increased the cytosolic Ca/sup 2 +/ concentration without any measurable delay. In contrast, there was a significant lag period (16 +/- 1.2 s) before platelet-derived growth factor (PDGF) increased cytosolic Ca/sup 2 +/ concentration. This lag was not diminished at high concentrations of either porcine or human PDGF. Similar results were obtained in 3T3 cells loaded with quin-2 or fura-2. The differences in the effects of bombesin, vasopressin, and PDGF on Ca/sup 2 +/ movements were also substantiated by measurements of /sup 45/Ca/sup 2 +/ effluxmore » and of cellular /sup 45/Ca/sup 2 +/ content. Activation of protein kinase C by phorbol esters inhibited Ca/sup 2 +/ mobilization induced by either bombesin or vasopressin. In contrast, phorbol esters had no effect on PDGF-induced cytosolic Ca/sup 2 +/ concentration increase or acceleration of /sup 45/Ca/sup 2 +/ efflux. Finally, bombesin and vasopressin caused a rapid increase in the production of inositol 1,4,5-trisphosphate and inositol 1,3,4-trisphosphate, whereas PDGF, even at a saturating concentration, exerted only a small effect. These results indicate that the signal transduction pathway activated by PDGF that lead to Ca/sup 2 +/ mobilization can be distinguished form those utilized by bombesin and vasopressin.« less