ABCMdb

ABCC1 p.Asp336Leu

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Publications

PMID: 12186871 [PubMed] Haimeur A et al: "Charged amino acids in the sixth transmembrane helix of multidrug resistance protein 1 (MRP1/ABCC1) are critical determinants of transport activity."

No. Sentence Comment

47 The sequences of the individual sense strands, with the altered codons underlined and the corresponding changes in amino acids indicated in parentheses were as follows: (K332D) 5Ј-CTC ATG AGC TTC TTC TTC GAC GCC ATC CAC GAC CTG-3Ј; (K332L) 5Ј-CTC ATG AGC TTC TTC TTC CTG GCC ATC CAC GAC CTG-3Ј; (H335E) 5Ј-GC TTC TTC TTC AAG GCC ATC GAG GAC CTG ATG ATG-3Ј; (H335L) 5Ј-GC TTC TTC TTC AAG GCC ATC TTG GAC CTG ATG ATG-3Ј; (H335Q) 5Ј-GC TTC TTC TTC AAG GCC ATC CAG GAC CTG ATG ATG-3Ј; (D336R) 5Ј-C AAG GCC ATC CAC CGG CTG ATG ATG TTT TCG-3Ј; (D336L) 5Ј-C AAG GCC ATC CAC CTG CTG ATG ATG TTT TCG-3Ј. Login to comment
94 Similarly, Asp336 was replaced with Leu as well as Arg. Login to comment
106 In the case of the MRP1-Lys332 mutants K332D and K332L (Fig. 3B) and the MRP1-Asp336 mutants D336L and D336R (Fig. 3D), LTC4 uptake was reduced to levels that were indistinguishable from those observed with vesicles prepared from empty vector-transfected control cells. Login to comment
125 In contrast, substitution of Asp336 with either Leu or Arg led to a complete loss of E217betaG uptake. Login to comment
126 Thus, as shown in Fig. 5C, MRP1-Asp336 mutants D336L and D336R exhibited the same E217betaG uptake activity as the empty vector control. Login to comment
142 D, wild-type MRP1 (f), MRP1 mutants D336L (Œ) and D336R (‚), and control empty pcDNA3.1(-) vector (E). Login to comment
152 However, this band is not detectable in [3 H]LTC4 photolabeled proteins from cells expressing comparable levels of the MRP1 mutants K332D and K332L or mutants D336L and D336R, indicating that these mutations abrogate photolabeling and hence binding of this compound. Login to comment
165 C, time courses of [3 H]E217betaG uptake by membrane vesicles prepared from HEK293T cells transfected with cDNAs encoding wild-type MRP1 (f), TM6 mutants D336L (Œ), and D336R (‚), and the empty pcDNA3.1(-) vector control (E). Login to comment
177 Substitution of Asp336 with Leu (D336L) reduced GSH uptake to ϳ25% of wild-type MRP1 levels, whereas substitution of this negatively charged residue with a positively charged residue (D336R) further reduced uptake of this tripeptide to just above basal levels observed with vesicles from the empty vector control (Fig. 7C). Login to comment
185 In contrast, MTX uptake was reduced by ϳ50% when Asp336 was substituted with Leu (D336L) and by ϳ65% when substituted with Arg (D336R) (not shown). Login to comment
204 Membrane vesicles were preincubated with acivicin and then incubated with [3 H]GSH in the presence of 30 ␮M apigenin in transport buffer for 20 min at 37 °C. A, K332D and K332L; B, H335E, H335L, and H335Q; C, D336L and D336R. Login to comment
208 F, WT-MRP1 (f); D336L (Œ); D336R (‚); vector control (E). Login to comment
217 Substitutions of MRP1-Asp336 had a more dramatic effect on MRP1 transport activity than substitutions of either Lys332 or His335 in that the D336L and D336R mutants did not transport four of the five organic anion substrates tested, and transport of the fifth, MTX, was reduced by at least 50%. Login to comment

PMID: 15155831 [PubMed] Haimeur A et al: "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)."

No. Sentence Comment

123 In our earlier study, we showed that substitution of the negatively charged TM6 Asp336 residue with Arg or Leu essentially eliminated the transport of both conjugated and unconjugated MRP1 organic anion substrates (Haimeur et al., 2002). Login to comment