ABCC1 p.Arg1249Asp
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PMID: 15208328
[PubMed]
Situ D et al: "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."
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107
The relative mean expression levels of the R1197E and R1249D mutants from 2 to 3 independent transfections were comparable with wild-type MRP1 (110 and 70%, respectively).
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ABCC1 p.Arg1249Asp 15208328:107:54
status: NEW113 Membrane vesicles prepared from HEK293T cells transfected with empty vector [pcDNA3.1] and vector containing the wild-type (WT-MRP1) and mutant (R1197E, R1202D, E1204K, and R1249D) cDNAs were immunoblotted with mAb QCRL-1. Shown is a representative immunoblot of membrane vesicles (1 and 2 g of protein) from a single transfection.
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ABCC1 p.Arg1249Asp 15208328:113:173
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.Arg1249Asp 15208328:118:722
status: NEW141 Transport Activities of TM16/17 Arg1197 and Arg1249 Mutants-Unlike the R1202D and E1204K mutants, oppositely charged substitutions of Arg1197 (R1197E) and Arg1249 (R1249D) did not adversely affect expression of MRP1 (Fig. 3A).
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ABCC1 p.Arg1249Asp 15208328:141:164
status: NEW143 Thus, levels of E217betaG uptake by both mutants were Ͻ10% of wild-type MRP1 levels (Fig. 5A), whereas LTC4 uptake by the R1197E and R1249D mutants was Ͻ15% of wild-type MRP1 (Fig. 5B).
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ABCC1 p.Arg1249Asp 15208328:143:139
status: NEW144 Uptake of E1SO4 by the R1197E mutant was Ͻ15% of wild-type MRP1, whereas uptake of this sulfated estrogen by the R1249D mutant was reduced by Ͼ90% (Fig. 5C).
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ABCC1 p.Arg1249Asp 15208328:144:119
status: NEW145 Finally, the R1197E and R1249D mutants showed MTX transport activity that was not significantly different from the empty vector control (Fig. 5D).
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ABCC1 p.Arg1249Asp 15208328:145:24
status: NEW177 Levels of 3 H-labeled organic anion uptake by membrane vesicles were prepared from cells expressing wild-type MRP1 (black bars), mutants R1197E, R1197K, R1249D, and R1249K (gray bars), and empty pcDNA3.1 vector control vesicles (open bars).
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ABCC1 p.Arg1249Asp 15208328:177:153
status: NEW229 Unlike Arg1202 and Glu1204 , substitution of Arg1197 and Arg1249 with oppositely charged residues did not adversely affect expression of MRP1 but instead caused a substantial reduction in transport activity. Our observations with respect to the R1249D mutant are consistent with those of Ren et al. (19) who reported that Ala substitution of Arg1249 impaired MRP1-mediated LTC4 transport and reduced vincristine resistance.
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ABCC1 p.Arg1249Asp 15208328:229:245
status: NEW