ABCC3 p.Trp1242Pro
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.Trp1242Pro 12388190:70:168
status: NEW104 Trp1242 was also replaced with a ␣-helix-disrupting residue (Pro; W1242P-MRP3).
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ABCC3 p.Trp1242Pro 12388190:104:73
status: NEW107 In contrast, the W1242P-MRP3 mutant was expressed at significantly lower levels, suggesting that this mutation affects the biogenesis or stability of the protein.
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ABCC3 p.Trp1242Pro 12388190:107:17
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.Trp1242Pro 12388190:108:199
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.Trp1242Pro 12388190:110:116
status: NEW112 In contrast, transport by W1242P-MRP3 was almost undetectable.
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ABCC3 p.Trp1242Pro 12388190:112:26
status: NEW122 [3 H]LTC4 uptake by the W1242P-MRP3 mutant was undetectable (not shown).
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ABCC3 p.Trp1242Pro 12388190:122:24
status: NEW123 Because of the consistently lower levels of W1242P-MRP3 expression and because this mutant did not transport either E217betaG or LTC4, it was not characterized further.
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ABCC3 p.Trp1242Pro 12388190:123:44
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.Trp1242Pro 12388190:130:240
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.Trp1242Pro 12388190:135:216
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.Trp1242Pro 12388190:199:124
status: NEW217 The loss of H-bonding and aromatic stacking interactions alone cannot fully account for the inactivity of the W1242P-MRP3 mutant, because the Ala, Cys, Phe, and Tyr mutants all retained some transport activity.
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ABCC3 p.Trp1242Pro 12388190:217:110
status: NEW