ABCMdb

ABCC1 p.Ser604Ala

Predicted by SNAP2:	A: D (75%), C: D (85%), D: D (95%), E: D (95%), F: D (95%), G: D (85%), H: D (91%), I: D (95%), K: D (95%), L: D (95%), M: D (91%), N: D (91%), P: D (95%), Q: D (91%), R: D (95%), T: D (85%), V: D (91%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: N, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: N, P: D, Q: D, R: D, T: N, V: D, W: D, Y: D,

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[hide] Transmembrane helix 11 of multidrug resistance pro... Biochemistry. 2004 Jul 27;43(29):9413-25. Zhang DW, Nunoya K, Vasa M, Gu HM, Theis A, Cole SP, Deeley RG
Transmembrane helix 11 of multidrug resistance protein 1 (MRP1/ABCC1): identification of polar amino acids important for substrate specificity and binding of ATP at nucleotide binding domain 1.
Biochemistry. 2004 Jul 27;43(29):9413-25., 2004-07-27 [PMID:15260484]

Abstract [show]
Human multidrug resistance protein 1 (MRP1) is an ATP binding cassette (ABC) transporter that confers resistance to many natural product chemotherapeutic agents and can transport structurally diverse conjugated organic anions. MRP1 has three polytopic transmembrane domains (TMDs) and a total of 17 TM helices. Photolabeling and mutagenesis studies of MRP1 indicate that TM11, the last helix in the second TMD, may form part of the protein's substrate binding pocket. We have demonstrated that certain polar residues within a number of TM helices, including Arg(593) in TM11, are determinants of MRP1 substrate specificity or overall activity. We have now extended these analyses to assess the functional consequences of mutating the remaining seven polar residues within and near TM11. Mutations Q580A, T581A, and S585A in the predicted outer leaflet region of the helix had no detectable effect on function, while mutation of three residues close to the membrane/cytoplasm interface altered substrate specificity. Two of these mutations affected only drug resistance. N597A increased and decreased resistance to vincristine and VP-16, respectively, while S605A decreased resistance to vincristine, VP-16 and doxorubicin. The third, S604A, selectively increased 17beta-estradiol 17-(beta-d-glucuronide) (E(2)17betaG) transport. In contrast, elimination of the polar character of the residue at position 590 (Asn in the wild-type protein) uniformly impaired the ability of MRP1 to transport potential physiological substrates and to confer resistance to three different classes of natural product drugs. Kinetic and photolabeling studies revealed that mutation N590A not only decreased the affinity of MRP1 for cysteinyl leukotriene 4 (LTC(4)) but also substantially reduced the binding of ATP to nucleotide binding domain 1 (NBD1). Thus, polar interactions involving residues in TM11 influence not only the substrate specificity of MRP1 but also an early step in the proposed catalytic cycle of the protein.

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No. Sentence Comment
8 The third, S604A, selectively increased 17 -estradiol 17-( -D-glucuronide) (E217 G) transport. Login to comment
47 Ser604 was converted to Ala and Thr, and Asn590 was mutated to Ala, Gln, and Asp. Login to comment
60 Mutations S585A, N590A, N590Q, N590D, N597A, and S604A were generated using the QuikchangeSite-Directed Mutagenesis kit (STRATAGENE, La Jolla, CA). Login to comment
68 CGG TTT CCC-3'), N590D (5'-CT TTG GCC TTG TTC GAT ATC CTC CGG TTT CCC-3'), N597A (5'-CTC CGG TTT CCC CTG GCC ATT CTC CCC ATG GT-3'), and S604A (5'-CTC CCC ATG GTC ATC GCC AGC ATC GTG CAG GC-3') After confirming all mutations by DNA Thermo Sequenase Cy5.5 and Cy5.0 dye terminator cycle sequencing (Amersham Biosciences) according to the manufacturer`s instructions, DNA fragments containing the desired mutations were transferred into pCEBV7-MRP1. Login to comment
151 The levels of LTC4 uptake by vesicles prepared from HEK transfectants expressing either wild-type MRP1 or mutations Q580A, T581A, S585A, N597A, S604A, and S605A were proportional to the relative expression levels of the wild-type and mutant proteins. Login to comment
155 However, substitution of Ser604 with Ala (S604A) increased the transport efficiency by approximately 2-fold. Login to comment
157 Thus, mutation S604A altered only the ability of MRP1 to transport the glucuronidated estrogen, whereas mutation N590A influenced the transport of both LTC4 and E217 G. Login to comment
168 To examine the influence of the N590A and S604A mutations more quantitatively, we compared their effect on the kinetic parameters of transport of both substrates (Figure 5). Login to comment
169 Mutation S604A had no effect on either the apparent Km or Vmax values for LTC4 uptake (Km 150 and 145 nM, and Vmax 89 and 84 pmol/ mg/min for wild-type MRP1 and mutation S604A, respectively) (Figure 5B and Table 1). Login to comment
172 For E217 G transport, the Vmax value for mutation S604A was increased by 20-25% relative to wild-type MRP1 (197 pmol/mg/min for wild-type MRP1 vs 241 pmol/mg/min for the mutation), while the apparent Km was decreased ~2.5-fold (1.7 and 0.7 µM for wild-type MRP1 and mutation S604A, respectively) (Figure 5C and Table 1). Login to comment
174 Thus, as observed with LTC4 as a substrate, mutation N590A decreased the Vmax/Km ratio for E217 G approximately 3-fold, whereas the S604A mutation increased the Vmax/Km ratio for this substrate approximately 3-fold. Login to comment
175 These changes in transport efficiency were mediated predominantly by a decrease in apparent affinity for both LTC4 and E217 G as a result of the S604A mutation, while the N590A mutation increased the apparent Km and decreased the Vmax for E217 G. Login to comment
203 Mutations Q580A, T581A, S585A, S604A, and S604T had no significant effect on the ability of MRP1 to confer resistance to any drug tested. Login to comment
216 In contrast, mutations N597A and S605A influenced only the drug resistance profile of MRP1, and mutation S604A affected the transport of only E217 G. Login to comment
270 In addition, although mutation S604T had no effect on any of the MRP1 functions tested, converting Ser604 to Ala decreased the apparent Km values and increased Vmax for E217 G uptake. Login to comment

[hide] A molecular understanding of ATP-dependent solute ... Cancer Metastasis Rev. 2007 Mar;26(1):15-37. Chang XB
A molecular understanding of ATP-dependent solute transport by multidrug resistance-associated protein MRP1.
Cancer Metastasis Rev. 2007 Mar;26(1):15-37., [PMID:17295059]

Abstract [show]
Over a million new cases of cancers are diagnosed each year in the United States and over half of these patients die from these devastating diseases. Thus, cancers cause a major public health problem in the United States and worldwide. Chemotherapy remains the principal mode to treat many metastatic cancers. However, occurrence of cellular multidrug resistance (MDR) prevents efficient killing of cancer cells, leading to chemotherapeutic treatment failure. Numerous mechanisms of MDR exist in cancer cells, such as intrinsic or acquired MDR. Overexpression of ATP-binding cassette (ABC) drug transporters, such as P-glycoprotein (P-gp or ABCB1), breast cancer resistance protein (BCRP or ABCG2) and/or multidrug resistance-associated protein (MRP1 or ABCC1), confers an acquired MDR due to their capabilities of transporting a broad range of chemically diverse anticancer drugs. In addition to their roles in MDR, there is substantial evidence suggesting that these drug transporters have functions in tissue defense. Basically, these drug transporters are expressed in tissues important for absorption, such as in lung and gut, and for metabolism and elimination, such as in liver and kidney. In addition, these drug transporters play an important role in maintaining the barrier function of many tissues including blood-brain barrier, blood-cerebral spinal fluid barrier, blood-testis barrier and the maternal-fetal barrier. Thus, these ATP-dependent drug transporters play an important role in the absorption, disposition and elimination of the structurally diverse array of the endobiotics and xenobiotics. In this review, the molecular mechanism of ATP-dependent solute transport by MRP1 will be addressed.

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No. Sentence Comment
112 Many mutations in TM11, such as N590A, F594A, N597A, S604A and S605A, also modulate the drug resistance profile of MRP1 [79, 80]. Login to comment

[hide] Molecular mechanism of ATP-dependent solute transp... Methods Mol Biol. 2010;596:223-49. Chang XB
Molecular mechanism of ATP-dependent solute transport by multidrug resistance-associated protein 1.
Methods Mol Biol. 2010;596:223-49., [PMID:19949927]

Abstract [show]
Millions of new cancer patients are diagnosed each year and over half of these patients die from this devastating disease. Thus, cancer causes a major public health problem worldwide. Chemotherapy remains the principal mode to treat many metastatic cancers. However, occurrence of cellular multidrug resistance (MDR) prevents efficient killing of cancer cells, leading to chemotherapeutic treatment failure. Over-expression of ATP-binding cassette transporters, such as P-glycoprotein, breast cancer resistance protein and/or multidrug resistance-associated protein 1 (MRP1), confers an acquired MDR due to their capabilities of transporting a broad range of chemically diverse anticancer drugs across the cell membrane barrier. In this review, the molecular mechanism of ATP-dependent solute transport by MRP1 will be addressed.

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No. Sentence Comment
104 Mutations of C43S in TM1 (112); P343A, K332L and K332D in TM6 (113, 114); W445A and P448A in TM8 (113, 115); T550A, T556A and P557A in TM10 (113, 116); N590A, F594A, P595A, N597A, S604A and S605A in TM11 (113, 117, 118); E1089Q, E1089A, E1089L, E1089N, K1092, S1097 and N1100 in TM14 (119, 120); R1197K in TM16 (121); Y1236F, T1241A, T1242A, T1242C, T1242S, T1242L, Y1243F, N1245A, W1246C, W1246A, W1246F, W1246Y or R1249K in TM17 (121-124) significantly affect MRP1 function. Login to comment