ABCB1 p.Tyr710Ala
| Predicted by SNAP2: | A: D (59%), C: N (57%), D: D (71%), E: D (71%), F: N (78%), G: D (66%), H: D (63%), I: N (53%), K: D (71%), L: D (53%), M: N (57%), N: D (59%), P: D (71%), Q: D (63%), R: D (63%), S: D (53%), T: D (53%), V: N (53%), W: N (57%), |
| 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, R: D, S: D, T: D, V: D, W: D, |
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[hide] The human multidrug resistance P-glycoprotein is i... FASEB J. 1999 Oct;13(13):1724-32. Loo TW, Clarke DM
The human multidrug resistance P-glycoprotein is inactive when its maturation is inhibited: potential for a role in cancer chemotherapy.
FASEB J. 1999 Oct;13(13):1724-32., [PMID:10506575]
Abstract [show]
The human multidrug resistance P-glycoprotein (P-gp) contributes to the phenomenon of multidrug resistance during cancer and AIDS chemotherapy. A potential novel strategy to circumvent the effects of P-gp during chemotherapy is to prevent maturation of P-gp during biosynthesis so that the transporter does not reach the cell surface. Here we report that immature, core-glycosylated P-gp that is prevented from reaching the cell surface by processing mutations or by proteasome inhibitors such as lactacystin or MG-132 exhibited no detectable drug-stimulated ATPase activity. Disulfide cross-linking analysis also showed that the immature P-gp did not exhibit ATP-induced conformational changes as found in the mature enzyme. In addition, the immature P-gp was more sensitive to trypsin than the mature enzyme. These results suggest that P-gp is unlikely to be functional immediately after synthesis. These differences in the structural and enzymatic properties of the mature and core-glycosylated, immature P-gp could potentially be used during chemotherapy, and should result in the search for compounds that can specifically inhibit the maturation of P-gp.
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No. Sentence Comment
64 Accordingly, the histidine-tagged 150 kDa protein of mutants G268V, G269V, and Y710A were isolated (Fig. 1, lanes 1, 3, and 5).
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ABCB1 p.Tyr710Ala 10506575:64:79
status: NEW66 To convert the processing mutants G268V, G269V, and Y710A to the mature enzyme, the mutants were synthesized in the presence of 10 M cyclosporin A to induce maturation (19).
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ABCB1 p.Tyr710Ala 10506575:66:52
status: NEW72 The mature enzyme of mutant Y710A had activities that were similar to wild-type P-gp.
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ABCB1 p.Tyr710Ala 10506575:72:28
status: NEW76 ATPase activity of P-gp that is prevented from undergoing maturation It was possible that the 150 kDa core-glycosylated P-gp of the processing mutants G268V, G269V, and Y710A were inactive because the point mutations inherently caused misfolding of the protein and subsequent retention in the endoplasmic reticulum.
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ABCB1 p.Tyr710Ala 10506575:76:169
status: NEW84 Equivalent amounts of histidine-tagged mature and core-glycosylated P-gp of wild-type and mutants G268V, G269V, and Y710A, isolated by nickel-chelate chromatography, were reconstituted with lipid and assayed for verapamil- (1 mM) and vinblastine- (0.05 mM) stimulated ATPase activities.
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ABCB1 p.Tyr710Ala 10506575:84:116
status: NEW88 HEK293 cells expressing histidine-tagged P-gp mutants G268V, G269V or Y710A were incubated with (ϩ) or without (-) 10 M cyclosporin A (cyclo) for 24 h. The cells were harvested and solubilized with n-dodecyl-beta-D-maltoside and the cell extracts were subjected to nickel-chelate chromatography with 20 mM imidazole in the wash buffers.
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ABCB1 p.Tyr710Ala 10506575:88:70
status: NEW