ABCC2 p.Thr1477Met
| Predicted by SNAP2: | A: N (97%), C: N (82%), D: N (97%), E: N (97%), F: N (61%), G: N (97%), H: N (97%), I: N (93%), K: N (97%), L: N (87%), M: N (93%), N: N (97%), P: N (93%), Q: N (97%), R: N (97%), S: N (97%), V: N (93%), W: N (57%), Y: N (61%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: D, G: N, H: N, I: D, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, V: N, W: D, Y: D, |
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[hide] Functional analysis of nonsynonymous single nucleo... Pharmacogenet Genomics. 2011 Aug;21(8):506-15. Megaraj V, Zhao T, Paumi CM, Gerk PM, Kim RB, Vore M
Functional analysis of nonsynonymous single nucleotide polymorphisms of multidrug resistance-associated protein 2 (ABCC2).
Pharmacogenet Genomics. 2011 Aug;21(8):506-15., [PMID:21691255]
Abstract [show]
BACKGROUND: Multidrug resistance-associated protein 2 (MRP2; ABCC2) mediates the biliary excretion of glutathione, glucuronide, and sulfate conjugates of endobiotics and xenobiotics. Single nucleotide polymorphisms (SNPs) of MRP2 contribute to interindividual variability in drug disposition and ultimately in drug response. OBJECTIVES: To characterize the transport function of human wild-type (WT) MRP2 and four SNP variants, S789F, A1450T, V417I, and T1477M. METHODS: The four SNP variants were expressed in Sf9 cells using recombinant baculovirus infection. The kinetic parameters [Km, (mumol/l); V(max), (pmol/mg/min); the Hill coefficient] of ATP-dependent transport of leukotriene C(4) (LTC(4)), estradiol-3-glucuronide (E(2)3G), estradiol-17beta-glucuronide (E(2)17G), and tauroursodeoxycholic acid (TUDC) were determined in Sf9-derived plasma membrane vesicles. Transport activity was normalized for expression level. RESULTS: The V(max) for transport activity was decreased for all substrates for S789F, and for all substrates except E(2)17G for A1450T. V417I showed decreased apparent affinity for LTC(4), E(2)3G, and E(2)17G, whereas transport was similar between wild-type (WT) and T1477M, except for a modest increase in TUDC transport. Examination of substrate-stimulated MRP2-dependent ATPase activity of S789F and A1450T, SNPs located in MRP2 nucleotide-binding domains (NBDs), demonstrated significantly decreased ATPase activity and only modestly decreased affinity for ATP compared with WT. CONCLUSION: SNPs in the NBDs (S789F in the D-loop of NBD1, or A1450T near the ABC signature motif of NBD2) variably decreased the transport of all substrates. V417I in membrane spanning domain 1 selectively decreased the apparent affinity for the glutathione and glucuronide conjugated substrates, whereas the T1477M SNP in the carboxyl terminus altered only TUDC transport.
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No. Sentence Comment
2 Objectives To characterize the transport function of human wild-type (WT) MRP2 and four SNP variants, S789F, A1450T, V417I, and T1477M.
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ABCC2 p.Thr1477Met 21691255:2:128
status: NEW7 V417I showed decreased apparent affinity for LTC4, E23G, and E217G, whereas transport was similar between wild-type (WT) and T1477M, except for a modest increase in TUDC transport.
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ABCC2 p.Thr1477Met 21691255:7:125
status: NEW10 V417I in membrane spanning domain 1 selectively decreased the apparent affinity for the glutathione and glucuronide conjugated substrates, whereas the T1477M SNP in the carboxyl terminus altered only TUDC transport.
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ABCC2 p.Thr1477Met 21691255:10:151
status: NEW48 Construction of recombinant baculovirus containing multidrug resistance protein 2 The plasmid (pEF6/V5-His-TOPO; Invitrogen) containing the WT MRP2 (NM_000392) or its SNP variants S789F, A1450T, V417I, and T1477M, was used to create the MRP2 baculovirus expression vector.
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ABCC2 p.Thr1477Met 21691255:48:206
status: NEW49 The pENTR 4 vector (Invitrogen) was mutated to generate a Hind III site using Quik Change II site-directed mutagenesis Kit (Stratagene; La Jolla, California, USA) using primers Hind IIIF and Hind IIIR (Hind IIIF: AGGCTCCAC- CATGGGAAGCTTCAGTCGACTGGATC; Hind IIIR: Table 1 Nucleotide sequence of variants in MRP2 leading to amino acid changes in multidrug resistance-associated protein 2 and their allelic frequencya SNP position Amino acid change Exon Location Allelic frequency Functional consequencesb C2366T S789F 18 NBD1 (D loop) 0.01 (Japanese) 52 G4348A A1450T 31 NBD2 (immediately after the ABC signature motif) 0.01 (Japanese) 52 G1249A V417I 10 MSD1 (between transmembrane helices 7 and 8) 0.125/0.312/0.184 (Japanese/Iranian/Moroccan) 27,46,47,52,58,59 C4430T T1477M 31 Carboxy terminal 0.006 (Japanese) MSD, membrane-spanning domain; NBD, nucleotide-binding domain; SNP, single nucleotide polymorphism.
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ABCC2 p.Thr1477Met 21691255:49:769
status: NEW56 The pENTR4M containing the WT, S789F, A1450T, V417I, and T1477M SNPs were sequenced (MWG Biotech, Inc., Huntsville, Alabama, USA).
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ABCC2 p.Thr1477Met 21691255:56:57
status: NEW96 There are no reports on the effects of SNP T1477M in the carboxy terminal on MRP2 function or expression; despite its low allelic frequency, the location of this SNP was of interest because the function of this portion of MRP2 is rarely studied [29].
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ABCC2 p.Thr1477Met 21691255:96:43
status: NEW97 Protein expression of wild-type multidrug resistance-associated protein 2 and single nucleotide polymorphism variants in Sf9 cells WT MRP2 and the SNP variants S789F, A1450T, V417I, and T1477M were expressed in Sf9 cells using recombinant baculovirus.
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ABCC2 p.Thr1477Met 21691255:97:186
status: NEW101 Statistical analysis of triplicate experiments showed that MRP2 expression was significantly reduced approximately 40% for S789F and T1477M variants, located in NBD1 and carboxy terminal region, respectively.
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ABCC2 p.Thr1477Met 21691255:101:133
status: NEW108 LTC4 and E23G were transported with classic Michaelis-Menten kinetics by WT MRP2; however, E217G and TUDC demonstrated positive Fig. 1 8000 6000 4000 Density(%)INT/mm2 2000 0 T1477M * V417IA1450TS789F * WTEV 185 KD EV WT S789F A1450T V417I T1477M (a) (b) Expression of WT multidrug resistance-associated protein 2 (MRP2) and its variants in Sf9 plasma membranes.
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ABCC2 p.Thr1477Met 21691255:108:175
status: NEWX
ABCC2 p.Thr1477Met 21691255:108:240
status: NEW125 The T1477M SNP located in the carboxyl terminal region induced modest but significant changes, and showed both increased Km (50%) and Vmax (13%) for TUDC, but a decrease in the Vmax for E23G (20%), whereas it did not influence the transport of other substrates (Fig. 2a-d; Table 2).
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ABCC2 p.Thr1477Met 21691255:125:4
status: NEW136 Four SNPs were selected for characterization, one in each of the two NBDs (S789F in NBD1 and A1450T in NBD2), one in MSD1 (V417I), and one in the carboxy terminal (T1477M), to probe how changes in these portions of MRP2 protein might impact its transport properties.
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ABCC2 p.Thr1477Met 21691255:136:164
status: NEW150 These data imply that valine 417 plays a critical and selective role in binding of glutathione Table 2 Kinetic parameters for transport of substrates by wild-type multidrug resistance-associated protein 2 and four single nucleotide polymorphism variants Substrates Kinetic parameters WT S789F A1450T V417I T1477M LTC4 Km 4 (1.8-6.5) 3 (1.8-4.4) 3 (2-3.6) 9 (7.8-12.7)* 6 (3.5-9) Vmax 1464 (1314-1713) 732 (648-816)* 658 (618-699)* 1366 (1200-1531) 1659 (1373-1945) E23G Km 103 (73-133) 235 (173-296)* 106 (64-148) 212 (95-330) 172 (88-230) Vmax 1458 (1339-1578) 615 (558-671)* 855 (746-964)* 1794 (1454-2134) 1157 (975-1338)* E217bG Km 84 (64-104) 72 (67-76) 88 (75-100) 263 (241-285)* 94 (89-100) Vmax 3154 (2691-3617) 1799 (1732-1866)* 2665 (2422-2907) 2647 (2520-2773) 2646 (2555-2737) HC 2.2 (1.4-3) 2.4 (2.1-2.6) 2 (1.6-2.4) 1.1 (1.1-1.2)* 1.8 (1.7-1.9) TUDC Km 71 (65-78) 64 (71-96) 71 (57-86) 74 (70-79) 109 (103-116)* Vmax 595 (563-627) 359 (343-376)* 424 (376-472)* 577 (553-600) 671 (645-699)* HC 2 (1.7-2.3) 2.3 (1.9-2.6) 1.8 (1.3-2.3) 2.6 (2.3-2.8) 2.2 (2-2.4) The kinetic parameters [Km (mmol/l); Vmax (pmol/mg/min); HC] of ATP-dependent transport of LTC4, E23G, E217G, and TUDC were determined in Sf9 plasma membrane vesicles.
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ABCC2 p.Thr1477Met 21691255:150:306
status: NEW166 Interestingly, the T1477M SNP located in the carboxy terminal region caused a selective decrease in the apparent affinity for TUDC but had no effect on the transport properties of other substrates.
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ABCC2 p.Thr1477Met 21691255:166:19
status: NEW168 Quantitative immunoblot analysis demonstrated a decreased expression of approximately 40% for two of the SNPs, S789Fand T1477M, relative to WT MRP2.
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ABCC2 p.Thr1477Met 21691255:168:120
status: NEW185 Similarly, expression of T1477M, in which the SNP is located 68 amino acid residues from the C-terminal of MRP2, was decreased to 62% of WT MRP2.
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ABCC2 p.Thr1477Met 21691255:185:25
status: NEW188 Although the amino acid change in T1477M could contribute to the localization signal, it is located in a good distance from the C-terminal, suggesting an alternative mechanism for its decreased expression.
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ABCC2 p.Thr1477Met 21691255:188:34
status: NEW189 From our studies, the data suggest that individuals with S789F and T1477M polymorphisms may have a lower expression level of MRP2 protein in the apical membrane of cells, and consequently, a reduced ability to export substrates.
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ABCC2 p.Thr1477Met 21691255:189:67
status: NEW199 V417I selectively inhibited the transport of glutathione and glucuronide-conjugated substrates, whereas T1477M only altered the transport of TUDC, a hydrophilic bile acid.
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ABCC2 p.Thr1477Met 21691255:199:104
status: NEW[hide] The apical conjugate efflux pump ABCC2 (MRP2). Pflugers Arch. 2007 Feb;453(5):643-59. Epub 2006 Jul 18. Nies AT, Keppler D
The apical conjugate efflux pump ABCC2 (MRP2).
Pflugers Arch. 2007 Feb;453(5):643-59. Epub 2006 Jul 18., [PMID:16847695]
Abstract [show]
ABCC2 is a member of the multidrug resistance protein subfamily localized exclusively to the apical membrane domain of polarized cells, such as hepatocytes, renal proximal tubule epithelia, and intestinal epithelia. This localization supports the function of ABCC2 in the terminal excretion and detoxification of endogenous and xenobiotic organic anions, particularly in the unidirectional efflux of substances conjugated with glutathione, glucuronate, or sulfate, as exemplified by leukotriene C(4), bilirubin glucuronosides, and some steroid sulfates. The hepatic ABCC2 pump contributes to the driving forces of bile flow. Acquired or hereditary deficiency of ABCC2, the latter known as Dubin-Johnson syndrome in humans, causes an increased concentration of bilirubin glucuronosides in blood because of their efflux from hepatocytes via the basolateral ABCC3, which compensates for the deficiency in ABCC2-mediated apical efflux. In this article we provide an overview on the molecular characteristics of ABCC2 and its expression in various tissues and species. We discuss the transcriptional and posttranscriptional regulation of ABCC2 and review approaches to the functional analysis providing information on its substrate specificity. A comprehensive list of sequence variants in the human ABCC2 gene summarizes predicted and proven functional consequences, including variants leading to Dubin-Johnson syndrome.
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No. Sentence Comment
151 These Abcc2-deficient mice are apparently healthy and fertile, as are Table 3 (continued) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references damaging transport function [47] Exon 30 c.4175_4180del6 p.R1392_M1393del2 DJS No ABCC2 protein in liver [170] Impaired sorting and trafficking [79] [79, 170] Exon 31 c.4348 G>A p.A1450T Possibly damaging Reduced protein levels [50] T: 0.010 [62] [62] Exon 31 c.4430 C>T p.T1477M Benign T: 0.006 [51] Exon 32 c.4544 G>A p.C1515Y Benign A: 0.047 rs8187710 A: 0.116 rs17222568 NCBI National Center for Biotechnology Information, SNP single nucleotide polymorphism, DJS Dubin-Johnson syndrome a As recommended by the Human Genome Variation Society (http://www.hgvs.org/mutnomen) and by ref [26], nucleotide position +1 is the A of the ATG of the translation initiation codon in the ABCC2 cDNA sequence, "c."
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ABCC2 p.Thr1477Met 16847695:151:630
status: NEW152 These Abcc2-deficient mice are apparently healthy and fertile, as are Table 3 (continued) Location Nucleotide changea Deduced effect on proteina Causing Dubin-Johnson syndromeb Predicted effect by PolyPhen databasec Experimentally proven functional consequence Average frequency of indicated nucleotide exchange in population NCBI SNP IDd and/or references damaging transport function [47] Exon 30 c.4175_4180del6 p.R1392_M1393del2 DJS No ABCC2 protein in liver [170] Impaired sorting and trafficking [79] [79, 170] Exon 31 c.4348 G>A p.A1450T Possibly damaging Reduced protein levels [50] T: 0.010 [62] [62] Exon 31 c.4430 C>T p.T1477M Benign T: 0.006 [51] Exon 32 c.4544 G>A p.C1515Y Benign A: 0.047 rs8187710 A: 0.116 rs17222568 NCBI National Center for Biotechnology Information, SNP single nucleotide polymorphism, DJS Dubin-Johnson syndrome a As recommended by the Human Genome Variation Society (http://www.hgvs.org/mutnomen) and by ref [26], nucleotide position +1 is the A of the ATG of the translation initiation codon in the ABCC2 cDNA sequence, "c."
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ABCC2 p.Thr1477Met 16847695:152:630
status: NEW