ABCC1 p.Pro69Ala
| Predicted by SNAP2: | A: N (87%), C: N (97%), D: N (78%), E: N (72%), F: N (93%), G: N (87%), H: N (97%), I: N (87%), K: N (87%), L: N (93%), M: N (93%), N: N (93%), Q: N (87%), R: N (93%), S: N (93%), T: N (93%), V: N (93%), W: N (93%), Y: N (93%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, Q: N, R: N, S: N, T: N, V: N, W: N, Y: N, |
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[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.Pro69Ala 12948592:46:257
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.Pro69Ala 12948592:104:122
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.Pro69Ala 12948592:117:63
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.Pro69Ala 12948592:180:106
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.Pro69Ala 12948592:188:339
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.Pro69Ala 12948592:193:69
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.Pro69Ala 12948592:179:106
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.Pro69Ala 12948592:187:327
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.Pro69Ala 12948592:192:69
status: NEW