ABCC1 p.Met443Leu
| Predicted by SNAP2: | A: D (63%), C: D (71%), D: D (85%), E: D (85%), F: D (63%), G: D (71%), H: D (85%), I: D (59%), K: D (91%), L: N (53%), N: D (80%), P: D (91%), Q: D (71%), R: D (91%), S: D (80%), T: D (66%), V: D (66%), W: D (91%), Y: D (71%), |
| Predicted by PROVEAN: | A: D, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[hide] Structural determinants of substrate specificity d... Drug Metab Dispos. 2008 Dec;36(12):2571-81. Epub 2008 Sep 5. Grant CE, Gao M, DeGorter MK, Cole SP, Deeley RG
Structural determinants of substrate specificity differences between human multidrug resistance protein (MRP) 1 (ABCC1) and MRP3 (ABCC3).
Drug Metab Dispos. 2008 Dec;36(12):2571-81. Epub 2008 Sep 5., [PMID:18775981]
Abstract [show]
Multidrug resistance proteins (MRPs) are members of the "C" branch of the ATP-binding cassette transporter superfamily. Human MRP1 transports a wide range of natural product drugs and structurally diverse conjugated and unconjugated organic anions. Its closest relative is MRP3. Despite their structural similarity, the homologs differ substantially in their substrate specificity. It is noteworthy that MRP1 transports glutathione (GSH) and GSH conjugates and displays GSH-stimulated transport of a number of unconjugated and conjugated compounds. In contrast, MRP3 does not transport GSH and is a poor transporter of GSH conjugates. However, both proteins transport glucuronide conjugates, such as 17beta-estradiol 17-(beta-D-glucuronide). We have constructed a series of MRP1/MRP3 hybrids and used them to identify a region of MRP1 that is critical for binding and transport of GSH conjugates such as leukotriene C(4) (LTC(4)). Substitution of this region encompassing transmembrane helices 8 and 9 and portions of cytoplasmic loops 4 and 5 of MRP1 with the equivalent region of MRP3 eliminated LTC(4) transport. Transport of other substrates was either unaffected or enhanced. We identified three residues in this region: Tyr(440), Ile(441), and Met(443), mutation of which differentially affected transport. It is noteworthy that substitution of Tyr(440) with Phe, as found in MRP3, reduced LTC(4) and GSH-stimulated estrone-3-sulfate transport without affecting transport of other substrates tested. The mutation increased the K(m) for LTC(4) 5-fold and substantially reduced photolabeling of MRP1 by both [3H]LTC(4) and the GSH derivative, azidophenacyl-[35S]GSH. These results suggest that Tyr(440) makes a major contribution to recognition of GSH and the GSH moiety of conjugates such as LTC(4).
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No. Sentence Comment
143 The Y440F/I441L/M443L virtually eliminated LTC4 transport (Fig. 3B) but also reduced E217betaG transport by approximately 80% (Fig. 3C).
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ABCC1 p.Met443Leu 18775981:143:16
status: NEW144 Transport of LTC4, E217betaG, E13SO4, and MTX by Y440F, I441L, and M443L MRP1 Mutant Proteins.
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ABCC1 p.Met443Leu 18775981:144:67
status: NEW156 The Y440F and M443L mutations each independently decreased initial rates of LTC4 transport by approximately 60 and 50%, respectively, whereas the I441L mutation had little or no effect (Fig. 3B).
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ABCC1 p.Met443Leu 18775981:156:14
status: NEW157 In contrast, E217betaG transport was decreased approximately 50% by both the I441L and M443L mutations but only 20% by the Y440F mutation (Fig. 3C).
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ABCC1 p.Met443Leu 18775981:157:87
status: NEW158 All three mutations significantly decreased E13SO4 transport in the presence of 2 mM S-methyl GSH, with the Y440F, I441L, and M443L mutations reducing transport at 1 min by approximately 65, 50, and 90%, respectively (Fig. 3D).
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ABCC1 p.Met443Leu 18775981:158:126
status: NEW193 Mutations Included 23 M443L/Y440F/1441L 24 A481G/V482A/M483V/M485V 25 V479L/A481G/V482A/M483V/M485V 26 A493K/H494Q/S497L/N500S 27 V479L/A481G/V482A/M483V/M485V 28 V479L/A481G/V482A/M483V/N500S 29 A493K/H494Q/S497L/N500S/N506S 30 A493K/H494Q/S497L/N506S/T487M/K488R/T489A/Y490F consequence, it was technically impossible to determine an accurate Km for LTC4.
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ABCC1 p.Met443Leu 18775981:193:22
status: NEW235 The M443L mutation reduced S-methyl GSH-stimulated E13SO4 transport by 90% in Sf21 cells (Fig. 3D).
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ABCC1 p.Met443Leu 18775981:235:4
status: NEW237 Thus, the affinity for azidophenacyl-GSH is severely affected by the M443L mutation.
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ABCC1 p.Met443Leu 18775981:237:69
status: NEW242 Effect of the Y440F, I441L, M443L, and Y440F/I441L Mutations on Resistance to Vincristine, Doxorubicin, and VP-16.
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ABCC1 p.Met443Leu 18775981:242:28
status: NEW243 Lastly, the drug-resistance profiles of Y440F, I441L, M443L, and Y440F/I441L mutant proteins were examined because unlike MRP1, the profile of resistance to natural product drugs conferred by MRP3 is restricted primarily to epipodophyllotoxins (Deeley et al., 2006).
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ABCC1 p.Met443Leu 18775981:243:54
status: NEW295 In contrast to the Y440F mutation, the conservatively substituted I441L mutation had no effect on LTC4 or MTX transport but decreased transport of both E217betaG and E13SO4, whereas the M443L mutation decreased transport of all three conjugated substrates but not TABLE 2 Relative Drug Resistance of HEK293 Cells Transfected with Wild-Type and Mutant MRP1 Transfectant Drug (Relative Resistance Factora ) Vincristine VP-16 Doxorubicin HEKMRP1 15.6 Ϯ 2.5 16.2 Ϯ 4.9 4.5 Ϯ 0.3 HEKMRP1-Y440F 2.4 Ϯ 0.5 (5.1) 2.7 Ϯ 0.8 (6.0) 1.3 Ϯ 0.2 (1.9) HEKMRP1-1441L 8.9 Ϯ 2.5 (9.7) 4.1 Ϯ 1.2 (4.4) 3.7 Ϯ 1.4 (4.1) HEKMRP1-M443L 6.5 Ϯ 1.2 (6.0) 5.8 Ϯ 0.5 (5.4) 3.8 Ϯ 0.7 (3.6) HEKMRP1-Y440F/1441L 3.9 Ϯ 1.0 (7.5) 1.3 Ϯ 0.3 (1.7) 1.2 Ϯ 0.2 (1.5) HEKMRP3 1.1 Ϯ 0.1 6.4 Ϯ 1.9 0.87 Ϯ 0.2 a The relative resistance factor was obtained by dividing the IC50 values for the wild-type or mutant MRP1-transfected cells by the IC50 value for cells transfected with the expression vector alone.
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ABCC1 p.Met443Leu 18775981:295:186
status: NEWX
ABCC1 p.Met443Leu 18775981:295:661
status: NEW[hide] Structural and functional properties of human mult... Curr Med Chem. 2011;18(3):439-81. He SM, Li R, Kanwar JR, Zhou SF
Structural and functional properties of human multidrug resistance protein 1 (MRP1/ABCC1).
Curr Med Chem. 2011;18(3):439-81., [PMID:21143116]
Abstract [show]
Multidrug ABC transporters such as P-glycoprotein (P-gp/MDR1/ABCB1) and multidrug resistance protein 1 (MRP1/ABCC1) play an important role in the extrusion of drugs from the cell and their overexpression can be a cause of failure of anticancer and antimicrobial chemotherapy. Recently, the mouse P-gp/Abcb1a structure has been determined and this has significantly enhanced our understanding of the structure-activity relationship (SAR) of mammalian ABC transporters. This paper highlights our current knowledge on the structural and functional properties and the SAR of human MRP1/ABCC1. Although the crystal structure of MRP1/ABCC1 has yet to be resolved, the current topological model of MRP1/ABCC1 contains two transmembrane domains (TMD1 and TMD2) each followed by a nucleotide binding domain (NBD) plus a third NH2-terminal TMD0. MRP1/ABCC1 is expressed in the liver, kidney, intestine, brain and other tissues. MRP1/ABCC1 transports a structurally diverse array of important endogenous substances (e.g. leukotrienes and estrogen conjugates) and xenobiotics and their metabolites, including various conjugates, anticancer drugs, heavy metals, organic anions and lipids. Cells that highly express MRP1/ABCC1 confer resistance to a variety of natural product anticancer drugs such as vinca alkaloids (e.g. vincristine), anthracyclines (e.g. etoposide) and epipodophyllotoxins (e.g. doxorubicin and mitoxantrone). MRP1/ABCC1 is associated with tumor resistance which is often caused by an increased efflux and decreased intracellular accumulation of natural product anticancer drugs and other anticancer agents. However, most compounds that efficiently reverse P-gp/ABCB1-mediated multidrug resistance have only low affinity for MRP1/ABCC1 and there are only a few effective and relatively specific MRP1/ABCC1 inhibitors available. A number of site-directed mutagenesis studies, biophysical and photolabeling studies, SAR and QSAR, molecular docking and homology modeling studies have documented the role of multiple residues in determining the substrate specificity and inhibitor selectivity of MRP1/ABCC1. Most of these residues are located in the TMs of TMD1 and TMD2, in particular TMs 4, 6, 7, 8, 10, 11, 14, 16, and 17, or in close proximity to the membrane/cytosol interface of MRP1/ABCC1. The exact transporting mechanism of MRP1/ABCC1 is unclear. MRP1/ABCC1 and other multidrug transporters are front-line mediators of drug resistance in cancers and represent important therapeutic targets in future chemotherapy. The crystal structure of human MRP1/ABCC1 is expected to be resolved in the near future and this will provide an insight into the SAR of MRP1/ABCC1 and allow for rational design of anticancer drugs and potent and selective MRP1/ABCC1 inhibitors.
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No. Sentence Comment
794 In addition, the Tyr440Phe, Ile441Leu, Met443Leu mutations decreased resistance to vincristine and etoposide 2-to 3-fold, whereas only the Tyr440Phe mutant displayed a major decrease in resistance to doxorubicin [374].
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ABCC1 p.Met443Leu 21143116:794:39
status: NEW