ABCC1 p.Lys347Asp
| Predicted by SNAP2: | A: N (72%), C: N (57%), D: N (78%), E: N (72%), F: D (59%), G: N (87%), H: N (82%), I: N (53%), L: N (53%), M: N (72%), N: N (87%), P: D (59%), Q: N (87%), R: N (97%), S: N (97%), T: N (82%), V: N (53%), W: D (63%), Y: D (53%), |
| Predicted by PROVEAN: | A: N, C: D, D: D, E: N, F: D, G: D, H: D, I: D, L: D, M: D, N: N, P: D, Q: N, R: N, S: N, T: N, 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
48 The sequences of the individual sense strands (with the corresponding amino acid changes indicated in parentheses, the altered codons underlined, and silent mutations introducing new restriction sites italicized) were as follows: K(D)332K, 5Ј-G AGC TTC TTC TTC AAG GCC ATC CAC GAC CTG-3Ј; K332R, 5Ј-G AGC TTC TTC TTC AGG GCC ATC CAC GAC CTG-3Ј; D(K)336E, 5Ј-C AAG GCC ATC CAC GAG CTC ATG ATG TTT TCC-3Ј; D336K, 5Ј-C AAG GCC ATC CAC AAG CTT ATG ATG TTT TCC-3Ј; K332D/D336K, 5Ј-GC TTC TTC TTC GAC GCC ATC CAC AAA CTG ATG ATG-3Ј; K319D, 5Ј-G TTT AAG GTG TTA TAC GAC ACG TTT GGG CCC-3Ј; K347D, 5Ј-GGG CCG CAG ATA TTA GAC TTG CTC ATC AAG-3Ј; K347L, 5Ј-GGG CCG CAA ATC TTA CTT TTG CTC ATC AAG-3Ј; D360K, 5Ј-GAC ACG AAG GCG CCA AAG TGG CAG GGC TAC-3Ј; R394D, 5Ј-C GTC AGT GGC ATG GAG ATC AAG ACC GCT GTC-3Ј; R394I, 5Ј-C GTC AGT GGC ATG ATC ATC AAG ACC GCT GTC-3Ј; K396E, 5Ј-GT GGC ATG AGG ATC GAG ACC GCT GTC ATT GGG-3Ј; K396I, 5Ј-GT GGC ATG AGG ATC ATC ACC GCT GTC ATT GGG-3Ј; K(E)396R, 5Ј-GGC ATG AGG ATC AGG ACC GCT GTC ATT GGG GC-3Ј; D430K, 5Ј-C AAC CTC ATG TCT GTG AAG GCT CAG AGG Fig. 1.
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ABCC1 p.Lys347Asp 15155831:48:655
status: NEW136 Lys319 was replaced with Asp (K319D), and Lys347 was replaced with Asp (K347D) as well as Leu (K347L).
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ABCC1 p.Lys347Asp 15155831:136:42
status: NEWX
ABCC1 p.Lys347Asp 15155831:136:72
status: NEW138 Thus the ability of the K319D, K347D, and K347L mutants to transport GSH was reduced by approximately 50% (Fig. 4C), whereas the transport of four other substrates (LTC4, E217betaG, E13SO4 and MTX) by these mutants remained comparable with wild-type MRP1 (Table 2).
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ABCC1 p.Lys347Asp 15155831:138:31
status: NEW148 MRP1 Mutant % Wild-Type MRP1 Transport Activity LTC4 GSH E217betaG E13SO4 MTX TM6 K332D Ͻ10 Ͻ10 100 100 100 K332R 40 20 100 100 100 D336K Ͻ10 Ͻ10 Ͻ10 15 45 D(K)336E 20 Ͻ10 25 25 45 K332D/D336K Ͻ10 Ͻ10 30 25 50 K319D 100 50 100 100 100 K347D 100 45 100 100 100 TM7 D360K 100 100 100 100 100 R394D 100 100 100 100 100 K396E 25 50 25 25 35 K(E)396R 100 100 100 100 100 TM8 D436K 40 30 20 30 55 D(K)436E 100 100 100 100 100 ECL5/TM11 D572R 100 100 100 100 100 E573R 100 100 100 100 100 D578R 100 100 100 100 100 R593E 35 30 Ͻ10 Ͻ10 40 R(E)593K 100 100 100 100 100 or substrate specificity of MRP1.
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ABCC1 p.Lys347Asp 15155831:148:283
status: NEW177 C, apigenin-stimulated [3 H]GSH uptake at 20 min by wild-type (WT) MRP1 (f), mutants K319D, K347D, and K347L (u), and empty pcDNA3.1(-) vector control (Ⅺ).
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ABCC1 p.Lys347Asp 15155831:177:92
status: NEW[hide] Arsenic transport by the human multidrug resistanc... J Biol Chem. 2004 Jul 30;279(31):32700-8. Epub 2004 May 25. Leslie EM, Haimeur A, Waalkes MP
Arsenic transport by the human multidrug resistance protein 1 (MRP1/ABCC1). Evidence that a tri-glutathione conjugate is required.
J Biol Chem. 2004 Jul 30;279(31):32700-8. Epub 2004 May 25., 2004-07-30 [PMID:15161912]
Abstract [show]
Inorganic arsenic is an established human carcinogen, but its metabolism is incompletely defined. The ATP binding cassette protein, multidrug resistance protein (MRP1/ABCC1), transports conjugated organic anions (e.g. leukotriene C(4)) and also co-transports certain unmodified xenobiotics (e.g. vincristine) with glutathione (GSH). MRP1 also confers resistance to arsenic in association with GSH; however, the mechanism and the species of arsenic transported are unknown. Using membrane vesicles prepared from the MRP1-overexpressing lung cancer cell line, H69AR, we found that MRP1 transports arsenite (As(III)) only in the presence of GSH but does not transport arsenate (As(V)) (with or without GSH). The non-reducing GSH analogs L-gamma-glutamyl-L-alpha-aminobutyryl glycine and S-methyl GSH did not support As(III) transport, indicating that the free thiol group of GSH is required. GSH-dependent transport of As(III) was 2-fold higher at pH 6.5-7 than at a more basic pH, consistent with the formation and transport of the acid-stable arsenic triglutathione (As(GS)(3)). Immunoblot analysis of H69AR vesicles revealed the unexpected membrane association of GSH S-transferase P1-1 (GSTP1-1). Membrane vesicles from an MRP1-transfected HeLa cell line lacking membrane-associated GSTP1-1 did not transport As(III) even in the presence of GSH but did transport synthetic As(GS)(3). The addition of exogenous GSTP1-1 to HeLa-MRP1 vesicles resulted in GSH-dependent As(III) transport. The apparent K(m) of As(GS)(3) for MRP1 was 0.32 microM, suggesting a remarkably high relative affinity. As(GS)(3) transport by MRP1 was osmotically sensitive and was inhibited by several conjugated organic anions (MRP1 substrates) as well as the metalloid antimonite (K(i) 2.8 microM). As(GS)(3) transport experiments using MRP1 mutants with substrate specificities differing from wild-type MRP1 suggested a commonality in the substrate binding pockets of As(GS)(3) and leukotriene C(4). Finally, human MRP2 also transported As(GS)(3). In conclusion, MRP1 transports inorganic arsenic as a tri-GSH conjugate, and GSTP1-1 may have a synergistic role in this process.
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No. Sentence Comment
69 MRP1 and MRP2 Expression Vectors and Transfections in HEK293T Cells-The construction and expression of wild-type MRP1 (WT-MRP1), wild-type MRP2 (WT-MRP2), and the MRP1 mutants K332L, D336K, K319D, and K347D in HEK293T cells have been described previously (31, 35-37).
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ABCC1 p.Lys347Asp 15161912:69:201
status: NEW204 To determine whether these amino acid residues are critical for transport of As(GS)3, transport assays were done using membrane vesicles prepared from HEK293T cells transfected with pcDNA3.1(-) (empty vector), WT-MRP1, D336K-MRP1, K332L-MRP1, K319D-MRP1, and K347D-MRP1 cDNAs.
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ABCC1 p.Lys347Asp 15161912:204:259
status: NEW207 Despite the fact that K319D-MRP1 and K347D-MRP1 have a selectively decreased ability to transport GSH, these mutants transported As(GS)3 at levels similar to WT-MRP1.
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ABCC1 p.Lys347Asp 15161912:207:37
status: NEW222 As(GS)3 transport by wild-type and mutant K332L, D336K, K319D, K347D-MRP1.
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ABCC1 p.Lys347Asp 15161912:222:63
status: NEW223 A, membrane vesicles prepared from HEK293T cells transfected with empty vector (pcDNA3.1(-)), wild-type MRP1 (WT-MRP1), or mutant MRP1 (K332L-MRP1, D336K-MRP1, K319D-MRP1, or K347D-MRP1) were immunoblotted with the MRP1-specific mAb QCRL-1 as described under "Experimental Procedures."
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ABCC1 p.Lys347Asp 15161912:223:175
status: NEW