ABCC1 p.Arg593Leu
| Predicted by SNAP2: | A: D (75%), C: D (80%), D: D (91%), E: D (91%), F: D (85%), G: D (80%), H: D (75%), I: D (85%), K: D (63%), L: D (85%), M: D (75%), N: D (75%), P: D (91%), Q: D (71%), S: D (71%), T: D (71%), V: D (85%), W: D (91%), Y: D (85%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: N, 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] Mutations of charged amino acids in or near the tr... Mol Pharmacol. 2004 Jun;65(6):1375-85. Haimeur A, Conseil G, Deeley RG, Cole SP
Mutations of charged amino acids in or near the transmembrane helices of the second membrane spanning domain differentially affect the substrate specificity and transport activity of the multidrug resistance protein MRP1 (ABCC1).
Mol Pharmacol. 2004 Jun;65(6):1375-85., [PMID:15155831]
Abstract [show]
Multidrug resistance protein 1 (MRP1) belongs to the ATP-binding cassette superfamily of transport proteins. In addition to drugs, MRP1 mediates the active transport of many conjugated and unconjugated organic anions. MRP1 consists of two membrane-spanning domains (MSD2 and MSD3) each followed by a nucleotide binding domain plus a third NH2-terminal MSD1. MSD2 contains transmembrane (TM) helices 6 through 11, and previously, we identified two charged residues in TM6 as having important but markedly different roles in MRP1 transport activity and substrate specificity by characterizing mutants containing nonconservative substitutions of Lys332 and Asp336. We have now extended these studies and found that the same-charge TM6 mutant K332R, like the nonconservatively substituted Lys332 mutants, exhibits a selective decrease in leukotriene C4 (LTC4) transport, associated with substantial changes in both Km and Vmax and LTC4 binding. The overall organic anion transport activity of the same-charge mutant of Asp336 (D336E) also remained very low, as observed for D336R. In addition, nonconservative substitutions of TM6-associated Lys319 and Lys347 resulted in a selective decrease in GSH transport. Of eight other charged residues in or proximal to TM7 to TM11 that were investigated, nonconservative substitutions of three of them [Lys396 (TM7), Asp436 (TM8), and Arg593 (TM11)] caused a substantial and global reduction in transport activity. However, unlike TM6 Asp336, wild-type transport activity could be reestablished in these MRP1 mutants by conservative substitutions. We conclude that MSD2-charged residues in or proximal to TM6, TM7, TM8, and TM11 play critical but differential roles in MRP1 transport activity and substrate specificity.
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No. Sentence Comment
51 TTC-3Ј; D430R, 5Ј-C AAC CTC ATG TCT GTG CGC GCT CAG AGG TTC-3Ј; D436K, 5Ј-C GCT CAG AGG TTC ATG AAG TTG GCC ACG TAC-3Ј; D(K)436E, 5Ј-C GCT CAG AGG TTC ATG GAA TTA GCC ACG TAC-3Ј; D572R, 5Ј-C TAC GTG ACC ATT CGC GAG AAC AAC ATC CTG G-3Ј; E573R, 5Ј-C GTG ACC ATT GAC CGG AAC AAC ATC CTG GAT G-3Ј; D578R, 5Ј-G AAC AAC ATC CTG CGG GCC CAG ACA GCC TTC G-3Ј; R593E, 5Ј-G GCC TTG TTC AAC ATC CTC GAG TTT CCC CTG AAC-3Ј; R593L, 5Ј-G GCC TTG TTC AAC ATC CTC CTG TTT CCC CTG AAC-3Ј; R(E)593K, 5Ј-GCC TTG TTC AAC ATC CTT AAG TTT CCC CTG AAC-3Ј.
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ABCC1 p.Arg593Leu 15155831:51:503
status: NEW184 In marked contrast, substitutions of TM11 Arg593 with Glu or Leu substantially reduced MRP1 transport activity.
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ABCC1 p.Arg593Leu 15155831:184:42
status: NEW185 As shown in Fig. 7, the LTC4 (Fig. 7A), GSH (Fig. 7D), and MTX (Fig. 7E) transport activities of the R593E and the R593L mutants were reduced by 70 to 80% relative to wild-type MRP1.
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ABCC1 p.Arg593Leu 15155831:185:115
status: NEW242 Time courses of [3 H]LTC4 uptake (A), [3 H]E217betaG uptake (B), and GSH-stimulated [3 H]E13SO4 uptake (C) by wild-type MRP1 (f), mutants R593E (‚), R593L (ƒ), and R(E)593K (F), and empty pcDNA3.1(-) vector control (E).
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ABCC1 p.Arg593Leu 15155831:242:156
status: NEW243 D, apigenin-stimulated [3 H]GSH uptake and [3 H]MTX uptake (E) at 20 min by wild-type (WT) MRP1 (f), mutants R593E, R593L, and R(E)593K (u), and empty pcDNA3.1(-) vector control (Ⅺ).
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ABCC1 p.Arg593Leu 15155831:243:116
status: NEW255 Thus, the nonconservatively substituted R593E and R593L mutants displayed a complete loss of E217betaG and E13SO4 transport and a substantial loss of LTC4, GSH, and MTX transport.
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ABCC1 p.Arg593Leu 15155831:255:50
status: NEW