ABCC1 p.Glu1204Asp
Predicted by SNAP2: | A: D (80%), C: D (71%), D: D (71%), F: D (91%), G: D (80%), H: D (91%), I: D (91%), K: D (91%), L: D (91%), M: D (85%), N: D (80%), P: D (91%), Q: D (75%), R: D (91%), S: D (85%), T: D (85%), V: D (85%), W: D (91%), Y: D (85%), |
Predicted by PROVEAN: | A: D, C: D, D: N, 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, Y: D, |
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[hide] Mutational analysis of ionizable residues proximal... J Biol Chem. 2004 Sep 10;279(37):38871-80. Epub 2004 Jun 18. Situ D, Haimeur A, Conseil G, Sparks KE, Zhang D, Deeley RG, Cole SP
Mutational analysis of ionizable residues proximal to the cytoplasmic interface of membrane spanning domain 3 of the multidrug resistance protein, MRP1 (ABCC1): glutamate 1204 is important for both the expression and catalytic activity of the transporter.
J Biol Chem. 2004 Sep 10;279(37):38871-80. Epub 2004 Jun 18., 2004-09-10 [PMID:15208328]
Abstract [show]
The multidrug resistance protein MRP1 is an ATP-dependent transporter of organic anions and chemotherapeutic agents. A significant number of ionizable amino acids are found in or proximal to the 17 transmembrane (TM) helices of MRP1, and we have investigated 6 of these at the cytoplasmic interface of TM13-17 for their role in MRP1 expression and transport activity. Opposite charge substitutions of TM13 Arg(1046) and TM15 Arg(1131) did not alter MRP1 expression nor did they substantially affect activity. In contrast, opposite charge substitutions of TM16 Arg(1202) and Glu(1204) reduced protein expression by >80%; however, MRP1 expression was not affected when Arg(1202) and Glu(1204) were replaced with neutral or same-charge residues. In addition, organic anion transport levels of the R1202L, R1202G, and R1202K mutants were comparable with wild-type MRP1. In contrast, organic anion transport by E1204L was substantially reduced, whereas transport by E1204D was comparable with wild-type MRP1, with the notable exception of GSH. Opposite charge substitutions of TM16 Arg(1197) and TM17 Arg(1249) did not affect MRP1 expression but substantially reduced transport. Mutants containing like-charge substitutions of Arg(1197) or Arg(1249) were also transport-inactive and no longer bound leukotriene C(4). In contrast, substrate binding by the transport-compromised E1204L mutant remained intact. Furthermore, vanadate-induced trapping of azido-ADP by E1204L was dramatically increased, indicating that this mutation may cause a partial uncoupling of the catalytic and transport activities of MRP1. Thus, Glu(1204) serves a dual role in membrane expression of MRP1 and a step in its catalytic cycle subsequent to initial substrate binding.
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No. Sentence Comment
5 In contrast, organic anion transport by E1204L was substantially reduced, whereas transport by E1204D was comparable with wild-type MRP1, with the notable exception of GSH.
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ABCC1 p.Glu1204Asp 15208328:5:95
status: NEW118 Immunoblots of membrane vesicle proteins prepared from cells expressing the Glu1204 mutants E1204L and E1204D were carried out as described in A. TABLE I Summary of organic anion transport activity of MRP1 mutants with substitutions of ionizable amino acids in and proximal to TM13 to TM17 of MSD3 Mutation % Wild-type MRP1 transport activitya E217betaG LTC4 E1SO4 MTX GSH TM13 R1046D 115 70 80 120 NDb TM14 D1084R Ͻ10 Ͻ10 15 25 Ͻ10 D1084E 80 20 65 90 20 TM15 R1131E 70 50 80 60 ND TM16 R1197E Ͻ10 Ͻ10 Ͻ15 Ͻ10 ND R1197K 20 Ͻ25 Ͻ20 Ͻ10 ND R1202G 115 115 75 70 ND R1202L 115 120 50 110 ND E1204L Ͻ10 50 10 110 Ͻ25 E1204D 100 115 100 115 Ͻ25 TM17 R1249D Ͻ10 Ͻ15 Ͻ10 Ͻ10 ND R1249K Ͻ10 10 Ͻ15 Ͻ10 ND a The values shown are means of duplicate or triplicate determinations and are derived from Fig. 2, 4, and 5 (see figure legends for details).
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ABCC1 p.Glu1204Asp 15208328:118:103
status: NEWX
ABCC1 p.Glu1204Asp 15208328:118:684
status: NEW124 Immunoblots showed that expression levels of the R1202G and R1202L mutants (Fig. 3B) and the E1204L and E1204D mutants (Fig. 3C) ranged from 80 to 225% of wild-type MRP1.
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ABCC1 p.Glu1204Asp 15208328:124:104
status: NEW134 To determine whether the substrate-selective loss of transport function observed in the E1204L mutant was because of the loss of the acidic character or the change in the size of the side chain, organic anion uptake by the same-charge mutant, E1204D, was also assessed.
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ABCC1 p.Glu1204Asp 15208328:134:243
status: NEW135 As shown in Fig. 4, E-H, and Table I, the E1204D mutant exhibited transport levels comparable with wild-type MRP1 for all substrates tested.
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ABCC1 p.Glu1204Asp 15208328:135:42
status: NEW137 As shown in Fig. 4I, both E1204L and E1204D exhibited a similar and substantial decrease in GSH transport levels (Ͼ75%).
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ABCC1 p.Glu1204Asp 15208328:137:37
status: NEW139 In general, the neutral mutants of Arg1202 showed only moderate and substrate-specific decreases in their transport activities. On the other hand, a neutral substitution of Glu1204 reduced or eliminated transport of all organic anions except MTX, whereas substitution with Asp had no effect with the exception that E1204D no longer transported GSH (see Table I for summary).
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ABCC1 p.Glu1204Asp 15208328:139:315
status: NEW172 E-H, uptake of 3 H-labeled organic anions by the membrane vesicles shown in Fig. 3C which were prepared from cells transfected with empty pcDNA3.1 vector (open bars), vector containing wild-type MRP1 cDNA (black bars), and the Glu1204 mutant E1204L and E1204D cDNAs (gray bars).
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ABCC1 p.Glu1204Asp 15208328:172:253
status: NEW206 Nevertheless, the substrate (LTC4)-binding site of E1204L remained intact. Furthermore, GSH transport remained very low, although other MRP1 transport activities of the same-charge E1204D mutant were comparable with wild-type MRP1.
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ABCC1 p.Glu1204Asp 15208328:206:181
status: NEW[hide] Structure, function, expression, genomic organizat... Int J Toxicol. 2006 Jul-Aug;25(4):231-59. Choudhuri S, Klaassen CD
Structure, function, expression, genomic organization, and single nucleotide polymorphisms of human ABCB1 (MDR1), ABCC (MRP), and ABCG2 (BCRP) efflux transporters.
Int J Toxicol. 2006 Jul-Aug;25(4):231-59., [PMID:16815813]
Abstract [show]
The ATP-binding cassette (ABC) transporters constitute a large family of membrane proteins, which transport a variety of compounds through the membrane against a concentration gradient at the cost of ATP hydrolysis. Substrates of the ABC transporters include lipids, bile acids, xenobiotics, and peptides for antigen presentation. As they transport exogenous and endogenous compounds, they reduce the body load of potentially harmful substances. One by-product of such protective function is that they also eliminate various useful drugs from the body, causing drug resistance. This review is a brief summary of the structure, function, and expression of the important drug resistance-conferring members belonging to three subfamilies of the human ABC family; these are ABCB1 (MDR1/P-glycoprotein of subfamily ABCB), subfamily ABCC (MRPs), and ABCG2 (BCRP of subfamily ABCG), which are expressed in various organs. In the text, the transporter symbol that carries the subfamily name (such as ABCB1, ABCC1, etc.) is used interchangeably with the corresponding original names, such as MDR1P-glycoprotein, MRP1, etc., respectively. Both nomenclatures are maintained in the text because both are still used in the transporter literature. This helps readers relate various names that they encounter in the literature. It now appears that P-glycoprotein, MRP1, MRP2, and BCRP can explain the phenomenon of multidrug resistance in all cell lines analyzed thus far. Also discussed are the gene structure, regulation of expression, and various polymorphisms in these genes. Because genetic polymorphism is thought to underlie interindividual differences, including their response to drugs and other xenobiotics, the importance of polymorphism in these genes is also discussed.
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No. Sentence Comment
411 In contrast, replacement with same charge residue (Glu1204Asp) did not have any effect, except for GSH.
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ABCC1 p.Glu1204Asp 16815813:411:51
status: NEW