ABCG2 p.Tyr469Phe
| Predicted by SNAP2: | A: D (80%), C: D (80%), D: D (95%), E: D (95%), F: D (66%), G: D (91%), H: D (85%), I: D (85%), K: D (95%), L: D (85%), M: D (91%), N: D (91%), P: D (95%), Q: D (91%), R: D (95%), S: D (91%), T: D (91%), V: D (85%), W: D (75%), |
| 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] Mutations of the central tyrosines of putative cho... Biochim Biophys Acta. 2015 Feb;1848(2):477-87. doi: 10.1016/j.bbamem.2014.11.006. Epub 2014 Nov 14. Gal Z, Hegedus C, Szakacs G, Varadi A, Sarkadi B, Ozvegy-Laczka C
Mutations of the central tyrosines of putative cholesterol recognition amino acid consensus (CRAC) sequences modify folding, activity, and sterol-sensing of the human ABCG2 multidrug transporter.
Biochim Biophys Acta. 2015 Feb;1848(2):477-87. doi: 10.1016/j.bbamem.2014.11.006. Epub 2014 Nov 14., [PMID:25445676]
Abstract [show]
Human ABCG2 is a plasma membrane glycoprotein causing multidrug resistance in cancer. Membrane cholesterol and bile acids are efficient regulators of ABCG2 function, while the molecular nature of the sterol-sensing sites has not been elucidated. The cholesterol recognition amino acid consensus (CRAC, L/V-(X)(1-5)-Y-(X)(1-5)-R/K) sequence is one of the conserved motifs involved in cholesterol binding in several proteins. We have identified five potential CRAC motifs in the transmembrane domain of the human ABCG2 protein. In order to define their roles in sterol-sensing, the central tyrosines of these CRACs (Y413, 459, 469, 570 and 645) were mutated to S or F and the mutants were expressed both in insect and mammalian cells. We found that mutation in Y459 prevented protein expression; the Y469S and Y645S mutants lost their activity; while the Y570S, Y469F, and Y645F mutants retained function as well as cholesterol and bile acid sensitivity. We found that in the case of the Y413S mutant, drug transport was efficient, while modulation of the ATPase activity by cholesterol and bile acids was significantly altered. We suggest that the Y413 residue within a putative CRAC motif has a role in sterol-sensing and the ATPase/drug transport coupling in the ABCG2 multidrug transporter.
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No. Sentence Comment
5 We found that mutation in Y459 prevented protein expression; the Y469S and Y645S mutants lost their activity; while the Y570S, Y469F, and Y645F mutants retained function as well as cholesterol and bile acid sensitivity.
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ABCG2 p.Tyr469Phe 25445676:5:127
status: NEW114 We found that the Y469F and Y645F mutants were active (Fig. 2B), indicating the importance of the phenyl ring, but not of a hydroxyl group at these positions for protein function.
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ABCG2 p.Tyr469Phe 25445676:114:18
status: NEW120 We found that the basal ATPase activity of the Y469F, Y570S and Y645F mutants showed a moderate (approximately 20%, p b 0.05) increase upon cholesterol addition, while the substrate stimulated ATP hydrolysis of the same mutants was significantly (50-100% increase, p b 0.01) accelerated by cholesterol loading (Fig. 2C).
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ABCG2 p.Tyr469Phe 25445676:120:47
status: NEW174 generated mammalian HEK 293 cells stably expressing the Y413S, Y469F, Y570S and Y645F mutants.
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ABCG2 p.Tyr469Phe 25445676:174:63
status: NEW250 BODIPY-prazosin Pheophorbide A Hoechst 33342 mitoxantrone wtABCG2 + + + + Y413S + + + + Y469F + + + + Y570S + + + + Y645F + + + + Fig. 8.
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ABCG2 p.Tyr469Phe 25445676:250:88
status: NEW