ABCMdb

ABCC1 p.Lys1141Arg

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Publications

PMID: 16230346 [PubMed] Conseil G et al: "Functional importance of three basic residues clustered at the cytosolic interface of transmembrane helix 15 in the multidrug and organic anion transporter MRP1 (ABCC1)."

No. Sentence Comment

6 Mutation of Lys1141 to either Glu or Arg reduced MRP1 expression, and routing to the plasma membrane was impaired. Login to comment
47 Substitutions of charged residues were generated in the pGEM-3Z- XmaI/MRP1 plasmid according to the manufacturer`s instructions with the following mutagenic primers (Integrated DNA Technologies, Inc., Coralville, IA), which also introduced an additional silent restriction site (substituted nucleotides are underlined): R1138E, 5Ј-CGT GGC TTC CTC CGA GCA ACT GAA GCG CCT CGA G-3Ј; R1138K, 5Ј-CGT GGC TTC CTC CAA GCA GCT TAA GCG CCT CGA G-3Ј; K1141E, 5Ј-CGG CAG CTG GAG CGC CTG GAG TCG GTC AGC-3Ј; K1141R, 5Ј-CCC GGC AGC TGC GGC GCC TCG AGT CGG-3Ј; R1142E, 5Ј-CCC GGC AGC TGA AGG AGC TCG AGT CGG TCA GCC G-3Ј;R1142K, 5Ј-CCC GGC AGC TGA AGA AGC TTG AGT CGG TCA GCC G-3Ј. Login to comment
122 B, HEK293T cells were transfected with expression vectors encoding WT-MRP1 and MRP1 mutants R1138E, R1138K, K1141E, K1141R, R1142E, and R1142K, and 48 h later, cells were probed with monoclonal antibody QCRL-3 and processed for confocal fluorescence microscopy using Alexa Fluor 488 conjugated secondary antibody. Login to comment
141 Kinetic parameters (Vmax and Km) were obtained after plotting the data according to the Michaelis-Menten equation for wild-type MRP1 and the K1141E and K1141R mutants (Table 1). Login to comment
143 However, although the Vmax for the K1141E mutant was unchanged, its Km for E217betaG transport was significantly increased by 4.4-fold (8.8 Ϯ 0.7 ␮M) when compared with the K1141R mutant (2.0 Ϯ 0.3 ␮M) and wild-type MRP1 (1.9 Ϯ 0.4 ␮M). Login to comment
160 TABLE 1 Kinetic parameters of vesicular uptake of E2 17betaG by wild-type and Lys1141 mutant MRP1 Km Vmax a Vmax/Km ؋ 103 ␮M pmol mg-1 min-1 mg/l/min WT-MRP1 1.9 Ϯ 0.4 604 Ϯ 36 0.32 K1141E 8.8 Ϯ 0.7 577 Ϯ 20 0.07 K1141R 2.0 Ϯ 0.3 964 Ϯ 42 0.48 a Vmax values have been corrected for differences in protein expression of the Lys1141 mutants relative to WT-MRP1 (Fig. 2A). Login to comment
165 Consistent with this interpretation, the orthovanadate-induced azido-ADP trapping by the same charge K1141R mutant, which had the least affected transport activity of all the mutants, was comparable with wild-type MRP1 (ϳ90%). Login to comment
204 Nevertheless, the vesicular transport activity of the K1141R mutant was similar to wild-type MRP1, as was its ability to be photolabeled with LTC4 and its ATPase activity. Login to comment

PMID: 21143116 [PubMed] He SM et al: "Structural and functional properties of human multidrug resistance protein 1 (MRP1/ABCC1)."

No. Sentence Comment

742 Notably, mutation of Lys1141 to either Glu or Arg impaired MRP1/ABCC1 expression and routing to the plasma membrane [354]. Login to comment
743 Substitution of Lys1141 with Glu (negatively chages) at TM15/CL7 interface decreased LTC4 transport by 70%, but an Arg substitution (positively charged) at this position did not; GSH transport by both Lys1141Glu and Lys1141Arg mutants was decreased by 40%, suggesting that the presence of a positive charge at Lys1141 was sufficient for LTC4 transport, whereas the less bulky side chain of Lys itself seemed important for GSH transport [354]. Login to comment
745 All mutants except Lys1141Arg showed substantially reduced trapping of 8-azido-[ 32P]ATP (40-60% that of wild-type MRP1), implicating that the ability of these mutants at TM15/CL7 interface to hydrolyze ATP is impaired and consequently disrupt the transport cycle and cause a decrease in transport activity. Login to comment