ABCC1 p.Pro51Ala
| Predicted by SNAP2: | A: N (72%), C: D (53%), D: D (71%), E: D (80%), F: D (66%), G: N (66%), H: D (71%), I: N (61%), K: D (80%), L: N (61%), M: D (59%), N: D (66%), Q: D (66%), R: D (75%), S: N (78%), T: D (59%), V: N (57%), W: D (80%), 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: D, M: D, N: D, Q: D, R: D, S: D, T: D, V: D, W: D, Y: D, |
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[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
751 The transport activity of the double mutant Pro42Ala/Pro51Ala was reduced by >80%.
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ABCC1 p.Pro51Ala 21143116:751:53
status: NEW[hide] Mutation of proline residues in the NH(2)-terminal... Biochim Biophys Acta. 2003 Sep 2;1615(1-2):103-14. Ito K, Weigl KE, Deeley RG, Cole SP
Mutation of proline residues in the NH(2)-terminal region of the multidrug resistance protein, MRP1 (ABCC1): effects on protein expression, membrane localization, and transport function.
Biochim Biophys Acta. 2003 Sep 2;1615(1-2):103-14., [PMID:12948592]
Abstract [show]
The Multidrug Resistance Protein, MRP1 (ABCC1) confers drug resistance and transports organic anions such as leukotriene C(4) (LTC(4)) and 17beta-estradiol 17-(beta-D-glucuronide) (E(2)17betaG). Previous studies showed that portions of the first membrane spanning domain (MSD1) and the cytoplasmic loop (CL3) connecting it to MSD2 are important for MRP1 transport function. We have replaced 12 prolines in MSD1 and CL3 with alanine and determined the effects of these substitutions on MRP1 expression and transport activity. All singly substituted MRP1-Pro mutants could be expressed in HeLa cells, except MRP1-P104A. The expressed mutants also transported LTC(4) and E(2)17betaG, and their K(m) (LTC(4)) values were similar to wild-type MRP1. Expression of the double mutant MRP1-P42/51A was reduced by >80% although it localized to the plasma membrane and transported organic anions. MRP1 expression was also reduced when the first transmembrane helix (amino acids 37-54) was deleted. In contrast, the phenotypes of the multiply substituted CL3 mutants MRP1-P196/205/207/209A and MRP1-P235/255A were comparable to wild-type MRP1. However, Pro(255)-substituted MRP1 mutants showed reduced immunoreactivity with a monoclonal antibody (MAb) whose epitope is located in CL3. We conclude that certain prolines in MSD1 and CL3 play a role in the expression and structure of MRP1.
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No. Sentence Comment
46 For the single substitutions of Pro with Ala in MSD1, the following sense mutagenic primers were used (substituted nucleotides are underlined): MRP1-P42A (5V-C GTG TGG GTG GCT TGT TTT TAC CTC TGG-3V), MRP1-P51A (5V-G GCC TGT TTC GCC TTC TAC TTC C-3V), MRP1-P69A (5V-CAG ATG ACA GCT CTC AAC-3V), MRP1-P104A (5V-C ATA TTC CTG GCC GCA GTG TTT CTG G-3V), MRP1-P110A (5V-GT TTC TGG TCA GCG CAA CTC TCT TGG-3V).
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ABCC1 p.Pro51Ala 12948592:46:206
status: NEW104 Immunoblots of membrane vesicles prepared from the cell lines expressing MSD1 MRP1 mutants containing single (P42A, P51A, P69A and P110A) and double (P42/51A) Pro substitutions detected with MAb QCRL-1 are shown in Fig. 2A. The relative expression levels of the different mutants ranged from < 20% to approximately 150% that of wild-type MRP1.
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ABCC1 p.Pro51Ala 12948592:104:116
status: NEW117 Similarly, the singly substituted MRP1-Pro mutants P42A, P51A, P69A, and P110A localized strongly to the plasma membrane, similar to wild-type MRP1 (MRP1-P42A and MRP1-P51A shown in Fig. 4A, middle two panels).
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ABCC1 p.Pro51Ala 12948592:117:57
status: NEWX
ABCC1 p.Pro51Ala 12948592:117:168
status: NEW141 (A) HeLa cells expressing wild-type MRP1, MRP1-P42A, MRP1-P51A, and MRP1-P42/51A were seeded at 1.5 Â 106 cells per well and processed 24 h later for indirect immunofluorescence and confocal microscopy.
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ABCC1 p.Pro51Ala 12948592:141:58
status: NEW180 Thus, all of the MSD1 Pro mutants retained the ability to transport LTC4 with TM1 mutants P42A, P51A, and P69A showing an approximately 30-50% decrease in relative LTC4 transport efficiency, while P110A (TM3) showed an increase of approximately 50%.
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ABCC1 p.Pro51Ala 12948592:180:96
status: NEW188 Results were expressed relative to wild-type Table 1 Kinetic parameters of [3 H]LTC4 uptake by membrane vesicles prepared from transfected HeLa cells expressing MRP1-Pro mutants Transfected cell line Km (nM) Vmax (pmol minÀ 1 mgÀ 1 ) Normalized Vmax MSD1 mutants WT-MRP1 128 80 80 P42A 139 35 41 P51A 109 55 50 P42/51A 103 15 48 P69A 142 46 42 P110A 150 73 124 CL3 mutants WT-MRP1 88 57 57 P196A 143 25 52 P205A 63 14 88 P207A 81 75 110 P209A 112 121 85 P196/205/207/209A 90 87 94 P235A 91 45 30 P255A 99 110 67 P235/255A 97 81 35 P272A 80 59 109 The kinetic parameters of [3 H]LTC4 uptake were determined by regression analysis of the Eadie-Hofstee transformed data.
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ABCC1 p.Pro51Ala 12948592:188:306
status: NEW193 E217hG uptake levels by the four single Pro MSD1 mutants P42A, P51A, P69A, and P110A were 48%, 43%, 95%, and 95% those of wild-type MRP1, respectively.
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ABCC1 p.Pro51Ala 12948592:193:63
status: NEW246 Models illustrating the predicted differences in the a-helical axis of TM1 in wild-type MRP1 and MRP1-Pro mutants P42A, P51A, and P42/ 51A.
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ABCC1 p.Pro51Ala 12948592:246:120
status: NEW179 Thus, all of the MSD1 Pro mutants retained the ability to transport LTC4 with TM1 mutants P42A, P51A, and P69A showing an approximately 30-50% decrease in relative LTC4 transport efficiency, while P110A (TM3) showed an increase of approximately 50%.
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ABCC1 p.Pro51Ala 12948592:179:96
status: NEW187 Results were expressed relative to wild-type Table 1 Kinetic parameters of [3 H]LTC4 uptake by membrane vesicles prepared from transfected HeLa cells expressing MRP1-Pro mutants Transfected cell line Km (nM) Vmax (pmol min 1 mg 1 ) Normalized Vmax MSD1 mutants WT-MRP1 128 80 80 P42A 139 35 41 P51A 109 55 50 P42/51A 103 15 48 P69A 142 46 42 P110A 150 73 124 CL3 mutants WT-MRP1 88 57 57 P196A 143 25 52 P205A 63 14 88 P207A 81 75 110 P209A 112 121 85 P196/205/207/209A 90 87 94 P235A 91 45 30 P255A 99 110 67 P235/255A 97 81 35 P272A 80 59 109 The kinetic parameters of [3 H]LTC4 uptake were determined by regression analysis of the Eadie-Hofstee transformed data.
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ABCC1 p.Pro51Ala 12948592:187:294
status: NEW192 E217hG uptake levels by the four single Pro MSD1 mutants P42A, P51A, P69A, and P110A were 48%, 43%, 95%, and 95% those of wild-type MRP1, respectively.
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ABCC1 p.Pro51Ala 12948592:192:63
status: NEW245 Models illustrating the predicted differences in the a-helical axis of TM1 in wild-type MRP1 and MRP1-Pro mutants P42A, P51A, and P42/ 51A.
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ABCC1 p.Pro51Ala 12948592:245:120
status: NEW