ABCG2 p.Arg482Pro
| Predicted by SNAP2: | A: D (91%), C: D (85%), D: D (95%), E: D (95%), F: D (91%), G: D (95%), H: D (95%), I: D (85%), K: D (85%), L: D (91%), M: D (85%), N: D (95%), P: D (95%), Q: D (95%), S: D (91%), T: D (91%), V: D (91%), W: D (95%), Y: D (95%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: D, P: D, Q: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] The nature of amino acid 482 of human ABCG2 affect... Protein Sci. 2006 Jul;15(7):1597-607. Ejendal KF, Diop NK, Schweiger LC, Hrycyna CA
The nature of amino acid 482 of human ABCG2 affects substrate transport and ATP hydrolysis but not substrate binding.
Protein Sci. 2006 Jul;15(7):1597-607., [PMID:16815914]
Abstract [show]
Several members of the ATP-binding cassette (ABC) transporter superfamily, including P-glycoprotein and the half-transporter ABCG2, can confer multidrug resistance to cancer cells in culture by functioning as ATP-dependent efflux pumps. ABCG2 variants harboring a mutation at arginine 482 have been cloned from several drug-resistant cell lines, and these variants differ in their substrate transport phenotype. In this study, we changed the wild-type arginine 482 in human ABCG2 to each one of the 19 other standard amino acids and expressed each one transiently in HeLa cells. Using the 5D3 antibody that recognizes a cell surface epitope of ABCG2, we observed that all the mutants were expressed at the cell surface. However, the mutant ABCG2 proteins differed markedly in transport activity. All of the variants were capable of transporting one or more of the substrates used in this study, with the exception of the R482K mutant, which is completely devoid of transport ability. Six of the mutants (R482G, R482H, R482K, R482P, R482T, and R482Y) and the wild-type protein (R482wt) were selected for studies of basal and stimulated ATPase activity and photoaffinity labeling with the substrate analog [125I]iodoarylazidoprazosin. Whereas these seven ABCG2 variants differed markedly in ATPase activity, all were able to specifically bind the substrate analog [125I]iodoarylazidoprazosin. These data suggest that residue 482 plays an important role in substrate transport and ATP turnover, but that the nature of this amino acid may not be important for substrate recognition and binding.
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No. Sentence Comment
7 Six of the mutants (R482G, R482H, R482K, R482P, R482T, and R482Y) and the wild-type protein (R482wt) were selected for studies of basal and stimulated ATPase activity and photoaffinity labeling with the substrate analog [125 I]iodoarylazidoprazosin.
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ABCG2 p.Arg482Pro 16815914:7:41
status: VERIFIED62 Of these 20 possible variants, three (R482F, R482L, R482P) have not previously been described.
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ABCG2 p.Arg482Pro 16815914:62:52
status: VERIFIED71 Analysis of the substrate binding properties of wild-type and six mutant ABCG2 proteins In order to further investigate the effects of the R482X mutations, we studied the drug-binding ability of a selection of ABCG2 mutants (R482G, R482H, R482K, R482P, R482T, and R482Y) and the wild-type ABCG2 (R482wt).
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ABCG2 p.Arg482Pro 16815914:71:246
status: VERIFIED73 We selected mutants R482H, R482P, and R482Y because they are partially deficient in rhodamine 123 transport, whereas mitoxantrone transport is intact.
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ABCG2 p.Arg482Pro 16815914:73:27
status: VERIFIED75 Of these six ABCG2 mutants plus the wild-type protein, biochemical analyses of R482H and R482P have not been described previously.
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ABCG2 p.Arg482Pro 16815914:75:89
status: VERIFIED86 We analyzed expression of ABCG2 in the membranes using the monoclonal antibody BXP-21 (Fig. 5A), which shows that the R482G, R482wt, and R482T membranes used here express less ABCG2, compared with the membranes expressing the R482H, R482K, R482P, and R482Y variants.
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ABCG2 p.Arg482Pro 16815914:86:240
status: VERIFIED89 The R482G, R482P, and R482T variants are stimulated 1.9-, 2.1-, and 1.8-fold, respectively, by the addition of 20 mM prazosin.
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ABCG2 p.Arg482Pro 16815914:89:11
status: VERIFIED96 Specific [125 I]IAAP photoaffinity labeling of crude membranes derived from HeLa cells expressing wild-type ABCG2 (R482wt) and the ABCG2 variants R482G, R482H, R482K, R482P, R482T, and R482Y.
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ABCG2 p.Arg482Pro 16815914:96:167
status: VERIFIED106 Basal and drug-stimulated ATPase activity of wild-type ABCG2 (R482wt) and ABCG2 variants R482G, R482H, R482K, R482P, R482T, and R482Y.
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ABCG2 p.Arg482Pro 16815914:106:110
status: VERIFIED