ABCB1 p.Thr945Ala

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PMID: 10585407 [PubMed] Loo TW et al: "Identification of residues in the drug-binding domain of human P-glycoprotein. Analysis of transmembrane segment 11 by cysteine-scanning mutagenesis and inhibition by dibromobimane."
No. Sentence Comment
77 There was moderate stimulation of verapamil-stimulated ATPase activities in mutants T945A (140%), G955V (143%), and F957A (126%).
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ABCB1 p.Thr945Ala 10585407:77:84
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79 Wild-type P-gp had an apparent affinity of 24 ␮M verapamil, while mutants F942A, T945A, Q946A, A947L, and Y953A had decreased apparent affinities of 93, 100, 165, 156, and 110 ␮M, respectively.
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ABCB1 p.Thr945Ala 10585407:79:88
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82 One mutant, T945A, showed a pronounced increase in activity (165% of wild-type enzyme).
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ABCB1 p.Thr945Ala 10585407:82:12
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128 TABLE I Drug-stimulated ATPase activity Mutant Drug Verapamil Vinblastine Colchicine Vmax Km Vmax Km Vmax Km % of WTa ␮M % of WT ␮M % of WT mM WT 100 24 100 5.4 100 0.62 I937S 94 22 93 6.1 100 0.69 F938A 106 32 96 5.1 96 0.68 G939V 62 8 45 4.0 165 0.26 I940S 93 32 93 5.6 93 0.65 T941A 100 25 104 5.5 100 0.66 F942A 88 93 30 5.1 24 0.80 S943A 92 26 100 5.2 85 0.62 F944A 93 14 105 5.3 101 0.64 T945A 140 100 165 8.3 56 0.65 Q946A 101 165 57 8.5 18 0.64 A947L 105 156 60 13.0 51 1.87 M948A 103 23 101 5.9 103 0.62 M949A 82 40 96 5.5 61 0.60 Y950A 109 37 119 5.1 99 0.62 F951A 94 31 99 5.2 101 0.64 S952A 108 36 123 5.1 91 0.69 Y953A 205 110 59 8.5 131 0.67 A954L 108 44 13 NDb 8 ND G955V 143 10 104 3.5 220 0.47 C956A 97 24 95 5.3 145 0.63 F957A 126 21 47 4.8 32 1.0 a WT, wild type. b ND, not determined due to low activity.
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ABCB1 p.Thr945Ala 10585407:128:408
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147 DISCUSSION Mutants G939V, F942A, T945A, Q946A, A947L, and Y953A in TM11 had altered apparent affinities for verapamil, vinblastine, or colchicine.
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ABCB1 p.Thr945Ala 10585407:147:33
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PMID: 21182301 [PubMed] Loo TW et al: "The W232R suppressor mutation promotes maturation of a truncation mutant lacking both nucleotide-binding domains and restores interdomain assembly and activity of P-glycoprotein processing mutants."
No. Sentence Comment
84 Baby hamster kidney (BHK) cells expressing A52-tagged wild-type P-gp or mutants G251V, G251V/W232R, W232R, W232A, N296A, E875A, or T945A were generated as described previously (25).
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ABCB1 p.Thr945Ala 21182301:84:131
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285 Stable BHK cell lines expressing mutants W232A, N296A, E875A, or T945A were generated.
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ABCB1 p.Thr945Ala 21182301:285:65
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290 Cells expressing mutant T945A were as resistant to vinblastine as cells with wild-type P-gp but showed decreased resistance to colchicine (P < 0.05).
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ABCB1 p.Thr945Ala 21182301:290:24
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299 Each value is average of triplicate assays ( SD. (B) Whole cell extracts of BHK cells expressing vector (control), A52-tagged wild-type, mutant W232A, N296A, E875A, or T945A P-gp were subjected to immunoblot analysis with monoclonal antibody against A52 or GAPDH.
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ABCB1 p.Thr945Ala 21182301:299:168
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303 Higher concentrations of verapamil were required for half-maximal activation (S50) of ATPase activity for mutants T945A (370 μM) and E875A (>1 mM) compared to wild-type P-gp (48 μM).
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ABCB1 p.Thr945Ala 21182301:303:114
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307 By contrast, the maximum activity of mutants W232A, E875A, and T945A were reduced relative to wild-type P-gp.
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ABCB1 p.Thr945Ala 21182301:307:63
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308 The S50 of mutants W232A (45 μM) and T945A (200 μM) differed from wild-type P-gp (102 μM) while those of mutants N296A (78 μM) and E875A (86 μM) were similar.
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ABCB1 p.Thr945Ala 21182301:308:43
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310 In summary, the E875A and T945A mutations altered both verapamiland rhodamine B-stimulated ATPase activity while the W232A and N296A mutations only affected rhodamine B-stimulated ATPase activity.
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ABCB1 p.Thr945Ala 21182301:310:26
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311 The large effect of the T945A mutation on ATPase activity is consistent with the observation that wild-type P-gp containing W232R exhibits verapamiland rhodamine-stimulated ATPase activity whereas wild-type P-gp containing T945R does not (42).
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ABCB1 p.Thr945Ala 21182301:311:24
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336 Histidine-tagged wild-type or mutant W232A, N296A, E875A, or T945A P-gp was expressed in HEK 293 cells and isolated by nickel-chelate chromatography.
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ABCB1 p.Thr945Ala 21182301:336:61
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PMID: 22360349 [PubMed] Mandal D et al: "Evidence for modulatory sites at the lipid-protein interface of the human multidrug transporter P-glycoprotein."
No. Sentence Comment
28 The desired nucleotide replacements were confirmed by Big-Dye version 3.1 (BD Sciences) nucleotide sequencing of the MDR1 open reading frame in recombinant plasmids pKM2-MDR1- V715A, -F716A, -I719A, -G723A, -I764A, -I765A, -I768A, -F770A, -L772A, -T837A, -I840A, -I864A, -I867A, -A871F, -T945A, -M948A, -F983A, -M986A, -V988A, -Q990A, and -V991A.
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ABCB1 p.Thr945Ala 22360349:28:288
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110 Stimulation of ATP Hydrolysis by cis-(Z)-Flupentixol and Verapamil cis-(Z)-flupentixol-mediated stimulation verapamil-mediated stimulation maximal stimulation (x-fold basal) concentration for half-maximal stimulation (μM) remark maximal stimulation (x-fold basal) concentration for half-maximal stimulation (μM) remark WT 7.3 ± 0.4 6.8 ± 1.5 5.6 ± 0.19 6.6 ± 1.04 V715A 6.2 ± 0.2 5.0 ± 0.9 6.4 ± 0.37 16.3 ± 3.3 V716A 5.1 ± 0.2 4.7 ± 1.1 NDb NDb a I719A 4.6 ± 0.08 4.7 ± 0.4 5.8 ± 0.26 6.5 ± 1.31 G723A 5.3 ± 0.3 10.93 ± 2.7 5.4 ± 0.1 11.6 ± 0.88 I764A 4.5 ± 0.4 4.1 ± 2 3.2 ± 0.26 27.9 ± 8.4 I765A 4.96 ± 0.2 2.3 ± 0.47 NDb NDb a I768A 4.8 ± 0.2 1.2 ± 0.43 4.8 ± 0.19 8.5 ± 1.4 F770A 6.6 ± 0.6 10.9 ± 3.9 8.6 ± 0.59 13.2 ± 3.2 L772A 3.6 ± 0.2 2.96 ± 0.9 3.2 ± 0.11 9.5 ± 1.6 T837A 1.1 ± 0.06 NDb a 2.6 ± 0.1 3.1 ± 0.9 I840A 4.0 ± 0.3 25.6 ± 6.5 6.9 ± 0.2 13.5 ± 0.5 I864A 0.6 ± 0.05 NDb a 4.1 ± 0.25 0.9 ± 1.04 I867A 10.2 ± 1.3 72.3 ± 18.5 10.2 ± 0.52 30.7 ± 3.1 A871F NDb NDb NDb NDb a T945A 5.0 ± 0.3 13.7 ± 3.1 6.4 ± 0.15 6.9 ± 0.71 M948A NDb NDb a 6.8 ± 1.5 44.4 ± 12.4 F983A 4.95 ± 0.36 19.59 ± 5.0 6.1 ± 0.38 6.6 ± 1.8 M986A 3.8 ± 0.3 2.6 ± 1.5 7.7 ± 0.76 30.0 ± 8.6 V988A 3.0 ± 0.2 21.4 ± 7.6 6.5 ± 0.31 16.9 ± 2.9 Q990A 1.8 ± 0.4 18.9 ± 2.6 a 7.7 ± 0.58 12.9 ± 3.7 V991A 3.9 ± 0.2 21.1 ± 5.0 5.9 ± 0.59 21.9 ± 7.2 a Mutants with <2-fold maximal stimulation (<25% of the wild-type level).
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ABCB1 p.Thr945Ala 22360349:110:1250
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PMID: 23104431 [PubMed] Gozalpour E et al: "Interaction of digitalis-like compounds with p-glycoprotein."
No. Sentence Comment
10 The uptake of [3 H]-N-methyl-quinidine (NMQ), the P-gp substrate in vesicular transport assays, was determined.The mutations I306A, F343A, F728A,T945A, and L975A abolished NMQ transport activity of P-gp.
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ABCB1 p.Thr945Ala 23104431:10:145
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45 Removal of the side chain resulted in loss of NMQ transport activity of five human P-gp mutants: I306A, F343A, F728A, T945A, and L975A, which seem to have key role in the transport of NMQ.
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ABCB1 p.Thr945Ala 23104431:45:118
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62 Ten different P-gp mutants were produced: L65A, I306A, F336A, I340A, F343A, F728A, F942A, T945A, L975A, and V982A and all mutations were confirmed by sequencing of full-length P-gp cDNA.
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ABCB1 p.Thr945Ala 23104431:62:90
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122 All the indicated amino acids were replaced by alanine to remove the side chain of the residue (L65A, I306A, F336A, I340A, F343A, F728A, F942A, T945A, L975A, and V982A).
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ABCB1 p.Thr945Ala 23104431:122:144
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132 NMQ transport activity of mutants L65A, F336A, I340A, F942A, andV982A as compared with wild-type P-gp ranged from 60 to 150%, whereas NMQ transport activity of I306A, F343A, F728A, T945A, and L975A varied between 8 and 30%.
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ABCB1 p.Thr945Ala 23104431:132:181
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180 Fig. 5.ߓ Western blot analysis (A) and NMQ transport activity of wild type and L65A, I306A, F336A, I340A, F343A, F728A, F942A, T945A, L975A, and V982A mutant P-gp (B).
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ABCB1 p.Thr945Ala 23104431:180:133
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190 The first group of mutants (I306A, F343A, F728A, T945A, and L975A) exhibited a significantly lower NMQ transport activity (8-30% of wild-type P-gp).
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ABCB1 p.Thr945Ala 23104431:190:49
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PMID: 25264938 [PubMed] Gozalpour E et al: "Convallatoxin: a new P-glycoprotein substrate."
No. Sentence Comment
56 Nine different P-gp mutants, I306A, F336A, I340A, F343A, F728A, F942A, T945A, L975A, and V982A, were produced and sequencing of full-length P-gp cDNA was used to confirm all mutations (Gozalpour et al., 2013).
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ABCB1 p.Thr945Ala 25264938:56:71
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154 Nine amino acids were replaced by alanine (I306A, F336A, I340A, F343A, F728A, F942A, T945A, L975A, and V982A) and P-gp mutants were expressed in HEK293 cells to produce membrane vesicles.
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ABCB1 p.Thr945Ala 25264938:154:85
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168 The transport activity of F336A, F942A, T945A and L975A for NMQ ranged from 49% to 57%, whereas I340A showed increased activity of 120% and V982A had about the same activity as wild type (Fig. 5B).
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ABCB1 p.Thr945Ala 25264938:168:40
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170 Convallatoxin and NMQ transport activity were not significantly different for I306A, F336A, I340A, F728A, F942A, T945A, and L975A (Fig. 5C), whereas they differed significantly for F343A and V982A (Fig. 5D and E).
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ABCB1 p.Thr945Ala 25264938:170:113
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254 The transport activity of F336A, F942A, T945A, L975A and V982A, were conserved (45-100% of wild type) (Fig. 5B) similar to our previous results (Gozalpour et al., 2013).
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ABCB1 p.Thr945Ala 25264938:254:40
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