ABCC3 p.Trp1242Tyr
| Predicted by SNAP2: | A: D (75%), C: D (71%), D: D (91%), E: D (85%), F: D (63%), G: D (80%), H: D (80%), I: D (80%), K: D (91%), L: D (85%), M: D (71%), N: D (80%), P: D (91%), Q: D (80%), R: D (85%), S: D (80%), T: D (85%), V: D (80%), Y: D (75%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, 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, Y: D, |
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[hide] Substitution of Trp1242 of TM17 alters substrate s... Am J Physiol Gastrointest Liver Physiol. 2003 Feb;284(2):G280-9. Epub 2002 Oct 9. Oleschuk CJ, Deeley RG, Cole SP
Substitution of Trp1242 of TM17 alters substrate specificity of human multidrug resistance protein 3.
Am J Physiol Gastrointest Liver Physiol. 2003 Feb;284(2):G280-9. Epub 2002 Oct 9., [PMID:12388190]
Abstract [show]
Multidrug resistance protein 3 (MRP3) is an ATP-dependent transporter of 17beta-estradiol 17beta(d-glucuronide) (E(2)17betaG), leukotriene C(4) (LTC(4)), methotrexate, and the bile salts taurocholate and glycocholate. In the present study, the role of a highly conserved Trp residue at position 1242 on MRP3 transport function was examined by expressing wild-type MRP3 and Ala-, Cys-, Phe-, Tyr-, and Pro-substituted mutants in human embryonic kidney 293T cells. Four MRP3-Trp(1242) mutants showed significantly increased E(2)17betaG uptake, whereas transport by the Pro mutant was undetectable. Similarly, the Pro mutant did not transport LTC(4). By comparison, LTC(4) transport by the Ala, Cys, Phe, and Tyr mutants was reduced by approximately 35%. The Ala, Cys, Phe, and Tyr mutants all showed greatly reduced methotrexate and leucovorin transport, except the Tyr mutant, which transported leucovorin at levels comparable with wild-type MRP3. In contrast, the MRP3-Trp(1242) substitutions did not significantly affect taurocholate transport or taurocholate and glycocholate inhibition of E(2)17betaG uptake. Thus Trp(1242) substitutions markedly alter the substrate specificity of MRP3 but leave bile salt binding and transport intact.
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No. Sentence Comment
70 G281CONSERVED ACA TTC GCT TTA AAC TTC ATG ATA CGA ATG ATG TCA G-3Ј), W1242Y (5Ј-G CAG GTG ACA TTC GCT TTA AAC TAC ATG ATA CGA ATG ATG TCA G-3Ј), and W1242P (5Ј-G CAG GTG ACA TTC GCT TTA AAC CCG ATG ATA CGA ATG ATG TCA G-3Ј).
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ABCC3 p.Trp1242Tyr 12388190:70:76
status: NEW103 These included nonconservative substitutions with a nonaromatic nonpolar amino acid (Ala; W1242A-MRP3) and a nonaromatic polar amino acid (Cys; W1242C-MRP3), as well as conservative substitutions with aromatic polar (Tyr; W1242Y-MRP3) and nonpolar (Phe; W1242F-MRP3) amino acids.
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ABCC3 p.Trp1242Tyr 12388190:103:222
status: NEW106 As shown in Fig. 2, wild-type MRP3 and the four mutants (W1242A-, W1242C-, W1242F-, and W1242Y-MRP3) were expressed at similar levels.
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ABCC3 p.Trp1242Tyr 12388190:106:88
status: NEW108 Mean expression levels of the mutant MRP3 proteins relative to wild-type MRP3 were as follows: W1242A, 1.1 Ϯ 0.3; W1242C, 1.0 Ϯ 0.2; W1242Y, 1.0 Ϯ 0.1; W1242F, 1.0 Ϯ 0.3; and W1242P, 0.6 Ϯ 0.2 (4-6 independent transfections).
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ABCC3 p.Trp1242Tyr 12388190:108:145
status: NEW110 Time courses of ATP-dependent [3 H]E217betaG uptake were determined for the W1242A-, W1242C-, W1242F-, W1242Y-, and W1242P-MRP3 mutants by using inside-out membrane vesicles prepared from transfected HEK293T cells (Fig. 3A).
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ABCC3 p.Trp1242Tyr 12388190:110:103
status: NEW111 Unexpectedly, four of the five mutants (W1242A-, W1242C-, W1242F-, and W1242Y-MRP3) transported this glucuronide substrate at levels that were substantially higher than those of wild-type MRP3.
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ABCC3 p.Trp1242Tyr 12388190:111:71
status: NEW113 At 3 min, [3 H]E217betaG uptake in membrane G282 CONSERVED TRP AND MRP3 (ABCC3) SUBSTRATE SPECIFICITY AJP-Gastrointest Liver Physiol • VOL 284 • FEBRUARY 2003 • www.ajpgi.org atUnivofNorthCarolina-AcqSrvcsonOctober,2012http://ajpgi.physiology.org/Downloadedfrom vesicles enriched for W1242A-, W1242C-, and W1242F-MRP3 was 2.5-to 3-fold higher than for wild-type MRP3, whereas [3 H]E217betaG uptake by the most conservatively substituted mutant, W1242Y-MRP3, was ϳ7-fold higher (Fig. 3B).
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ABCC3 p.Trp1242Tyr 12388190:113:467
status: NEW120 [3 H]LTC4 uptake by the W1242A-, W1242F-, and W1242Y-MRP3 mutants was somewhat less than the wild-type MRP3 transport activity (Fig. 4A).
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ABCC3 p.Trp1242Tyr 12388190:120:46
status: NEW128 At 10 min, ATP-dependent [3 H]MTX uptake levels by the W1242A, W1242C, W1242F, and W1242Y Fig. 3.
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ABCC3 p.Trp1242Tyr 12388190:128:83
status: NEW130 A: time course of ATP-dependent [3 H]E217betaG uptake in membrane vesicles prepared from HEK293T cells transfected with empty vector (ᮀ), wild-type MRP3 (s), and mutant [W1242A (), W1242C (}), W1242F (F), W1242Y (Œ), and W1242P (ƒ)] cDNA expression vectors.
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ABCC3 p.Trp1242Tyr 12388190:130:218
status: NEW135 Top: MRP3 expression in membrane vesicles prepared from human embryonic kidney (HEK) 293T cells transfected with empty vector [pcDNA3.1(ϩ)], wild-type (WT-MRP3), and mutant (W1242A, W1242C, W1242F, W1242Y, and W1242P) MRP3 cDNAs was determined by immunoblotting with MAb M3II-9, and relative levels of expression were estimated by densitometry.
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ABCC3 p.Trp1242Tyr 12388190:135:204
status: NEW145 Only the most conservatively substituted W1242Y-MRP3 mutant transports [3 H]leucovorin.
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ABCC3 p.Trp1242Tyr 12388190:145:41
status: NEW147 To determine if Trp1242 substitutions also affected MRP3-mediated transport of the latter substrate, [3 H]leucovorin uptake into membrane vesicles prepared from transfected cells expressing wild-type MRP3 and W1242A-, W1242C-, W1242F-, and W1242Y-MRP3 mutants was examined.
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ABCC3 p.Trp1242Tyr 12388190:147:240
status: NEW149 Of the four Trp1242 mutants tested, only the most conservatively substituted mutant, W1242Y-MRP3, transported [3 H]leucovorin at levels comparable to those of wild-type MRP3.
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ABCC3 p.Trp1242Tyr 12388190:149:85
status: NEW151 Time course of [3 H]methotrexate (MTX) uptake and MTX- mediated inhibition of [3 H]E217betaG uptake by wild-type and Trp1242 mutant MRP3 proteins. A: ATP-dependent uptake of [3 H]MTX was measured in membrane vesicles prepared from HEK293T cells transfected with empty pcDNA3.1(ϩ) vector (ᮀ), wild-type (s), and mutant [W1242A (), W1242C (}), W1242F (F), and W1242Y (Œ)] MRP3 cDNA expression vectors. Membrane vesicles were incubated at 37°C with 1 M [3 H]MTX and ATP or AMP in transport buffer.
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ABCC3 p.Trp1242Tyr 12388190:151:377
status: NEW161 Taurocholate uptake by the W1242A-, W1242C-, W1242F-, and W1242Y-MRP3 mutants was then examined and, in all cases, was not significantly different from uptake by wild-type MRP3 (Fig. 7B).
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ABCC3 p.Trp1242Tyr 12388190:161:58
status: NEW162 Consistent with this observation, [3 H]E217betaG uptake by W1242A-, W1242C-, W1242F-, and W1242Y-MRP3 could still be inhibited by taurocholic acid (40-60%) at concentrations of 50 and 100 M (Fig. 7C).
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ABCC3 p.Trp1242Tyr 12388190:162:90
status: NEW170 Cells were transfected with empty vector [pcDNA3.1(ϩ)], wild-type, and mutant (W1242A, W1242C, W1242F, and W1242Y) MRP3 cDNA expression.
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ABCC3 p.Trp1242Tyr 12388190:170:113
status: NEW171 C: membrane vesicles from cells expressing wild-type and W1242A, W1242C, W1242F, and W1242Y mutant MRP3 were incubated at 37°C with 400 nM [3 H]E217betaG in transport buffer and other components for 3 min in the absence (open bars) or presence of taurocholic acid (50 M, grey bar; 100 M, solid bar).
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ABCC3 p.Trp1242Tyr 12388190:171:85
status: NEW173 [3 H]leucovorin uptake by wild-type and Trp1242 mutant MRP3 proteins. A: uptake of [3 H]leucovorin was measured in membrane vesicles prepared from HEK293T cells transfected with empty vector [pcDNA3.1(ϩ)], wild-type, and Trp1242 mutant (W1242A, W1242C, W1242F, and W1242Y) MRP3 cDNA expression vectors. Membrane vesicles were incubated at 37°C with 250 M [3 H]leucovorin and ATP or AMP in transport buffer for 20 min.
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ABCC3 p.Trp1242Tyr 12388190:173:271
status: NEW196 Membrane vesicles from cells expressing wild-type MRP3 (WT-MRP3) and W1242A, W1242C, W1242F, and W1242Y mutant MRP3 were incubated at 37°C with 400 nM [3 H]E217betaG in transport buffer and other components for 3 min in the absence (open bars) or presence of glycocholate (50 M, grey bar; 100 M, solid bar).
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ABCC3 p.Trp1242Tyr 12388190:196:97
status: NEW199 Transport activities of variously substituted MRP3-Trp1242 mutants Substrate Transport Activity W1242A W1242C W1242F W1242Y W1242P E217betaG 1 1 1 11 222 LTC4 2 22 2 2 222 MTX 222 222 222 222 n.d.
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ABCC3 p.Trp1242Tyr 12388190:199:117
status: NEW204 However, the highest level of E217betaG uptake was observed with W1242Y-MRP3, which is the most conservatively substituted mutant with respect to steric bulk, aromaticity, and H-bonding capability of the lateral side chain.
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ABCC3 p.Trp1242Tyr 12388190:204:65
status: NEW229 However, if they do, they must do so in a somewhat different way for leucovorin than for MTX, which may account for the difference in affinities of these compounds for MRP3 as well as for the ability of the W1242Y-MRP3 mutant to transport the former but not the latter drug.
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ABCC3 p.Trp1242Tyr 12388190:229:207
status: NEW