ABCB1 p.Pro709Ala
| Predicted by SNAP2: | A: N (87%), C: N (93%), D: N (78%), E: N (82%), F: N (93%), G: N (93%), H: N (97%), I: N (93%), K: N (93%), L: N (93%), M: N (93%), N: N (87%), Q: N (87%), R: N (93%), S: N (93%), T: N (93%), V: N (93%), W: N (93%), Y: N (97%), |
| 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] The W232R suppressor mutation promotes maturation ... Biochemistry. 2011 Feb 8;50(5):672-85. Epub 2011 Jan 11. Loo TW, Bartlett MC, Clarke DM
The W232R suppressor mutation promotes maturation of a truncation mutant lacking both nucleotide-binding domains and restores interdomain assembly and activity of P-glycoprotein processing mutants.
Biochemistry. 2011 Feb 8;50(5):672-85. Epub 2011 Jan 11., 2011-02-08 [PMID:21182301]
Abstract [show]
ATP-binding cassette (ABC) proteins contain two nucleotide-binding domains (NBDs) and two transmembrane (TM) domains (TMDs). Interdomain interactions and packing of the TM segments are critical for function, and disruption by genetic mutations contributes to disease. P-glycoprotein (P-gp) is a useful model to identify mechanisms that repair processing defects because numerous arginine suppressor mutations have been identified in the TM segments. Here, we tested the prediction that a mechanism of arginine rescue was to promote intradomain interactions between TM segments and restore interdomain assembly. We found that suppressor W232R(TM4/TMD1) rescued mutants with processing mutations in any domain and restored defective NBD1-NBD2, NBD1-TMD2, and TMD1-TMD2 interactions. W232R also promoted packing of the TM segments because it rescued a truncation mutant lacking both NBDs. The mechanism of W232R rescue likely involved intradomain hydrogen bond interactions with Asn296(TM5) since only N296A abolished rescue by W232R and rescue was only observed when Trp232 was replaced with hydrogen-bonding residues. In TMD2, suppressor T945R(TM11) also promoted packing of the TM segments because it rescued the truncation mutant lacking the NBDs and suppressed formation of alternative topologies. We propose that T945R rescue was mediated by interactions with Glu875(TM10) since T945E/E875R promoted maturation while T945R/E875A did not.
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No. Sentence Comment
57 The red balls show the locations of Trp232 and the processing mutations at positions 251 (G251V), 490 (ΔY490), 709 (P709A), 722 (G722A), and 1260 (L1260A).
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ABCB1 p.Pro709Ala 21182301:57:122
status: NEW67 Mutations were introduced into wild-type P-gp or processing mutants containing processing mutations in different domains (G251V in TMD1, ΔY490 in NBD1, P709A in the linker region, G722A in TMD2, or L1260A in NBD2) as described previously (28).
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ABCB1 p.Pro709Ala 21182301:67:158
status: NEW125 The W232R mutation was introduced into mutants P709A (linker region), G722A (TMD2), or L1260A (NBD2).
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ABCB1 p.Pro709Ala 21182301:125:47
status: NEW[hide] New light on multidrug binding by an ATP-binding-c... Trends Pharmacol Sci. 2006 Apr;27(4):195-203. Epub 2006 Mar 20. Shilling RA, Venter H, Velamakanni S, Bapna A, Woebking B, Shahi S, van Veen HW
New light on multidrug binding by an ATP-binding-cassette transporter.
Trends Pharmacol Sci. 2006 Apr;27(4):195-203. Epub 2006 Mar 20., [PMID:16545467]
Abstract [show]
ATP-binding-cassette (ABC) multidrug transporters confer multidrug resistance to pathogenic microorganisms and human tumour cells by mediating the extrusion of structurally unrelated chemotherapeutic drugs from the cell. The molecular basis by which ABC multidrug transporters bind and transport drugs is far from clear. Genetic analyses during the past 14 years reveal that the replacement of many individual amino acids in mammalian multidrug resistance P-glycoproteins can affect cellular resistance to drugs, but these studies have failed to identify specific regions in the primary amino acid sequence that are part of a defined drug-binding pocket. The recent publication of an X-ray crystallographic structure of the bacterial P-glycoprotein homologue MsbA and an MsbA-based homology model of human P-glycoprotein creates an opportunity to compare the original mutagenesis data with the three-dimensional structures of transporters. Our comparisons reveal that mutations that alter specificity are present in three-dimensional 'hotspot' regions in the membrane domains of P-glycoprotein.
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No. Sentence Comment
58 Although mutation of only one of these residues (L975A, V981A and F983A) has no effect on the phenotype of the protein [20], double mutations either completely inhibit (V981A/F983A and L975A/V981A) or cause 50% inhibition (L975A/F983A) of Table 1.
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ABCB1 p.Pro709Ala 16545467:58:597
status: NEW59 Published mutations in human and murine P-glycoprotein that alter drug transport in cells Location of mutation Mutation Refs Mutation Refs Mutation Refs Transmembrane helices H61A and others [14] I214L [60] L868W [59] G64R [15] P223A [65] I936A [21] L65R [15] S224P [60] F938A [21] Q139[H/P/R] [60] I306R [18] S939[A/C/T/Y/W/D/F] [21,22] G141V [17] F335A [16] T941A [21] G185V [61,62] V338A [66] Q942A [21] I186N [61] G338A [67,68] A943G [21] G187V [17] A339P [67,68] Y946A [21] G187E [60] G341A [66] S948A [21] A192T [60] S344[A/T/C/Y] [66] Y949A [21] F200L [60] N350I [19] C952A [21] F204S [60] P709A [65] F953A [21] R206L [60] G830V [17] L975A [20] W208G [60] I837L [23] F978A [16] K209E [60] N839I [23] V981A [20] L210I [60] I862F [19] F983A [20] T211P [60] L865F [19] F978A [16] V213A [60] P866A [65] N988D [59] Intracellular domain T169I [60] K177I [60] G288V [17] R170L [60] E180G [60] A931T [19] L171P [60] G181R [60] F934A [21] T172P [60] G183D [60] G935A [21] S176P [60] D184N [60] NBD D555N [63] K1076M [69] E1197Q [64] D558N [64] D1093N [64] D1203N [64] D592N [64] E1125Q [64] D1237N [64] E604Q [64] S1173A [70] E1249Q [64] Review TRENDS in Pharmacological Sciences Vol.27 No.
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ABCB1 p.Pro709Ala 16545467:59:597
status: NEW[hide] Thapsigargin or curcumin does not promote maturati... Biochem Biophys Res Commun. 2004 Dec 10;325(2):580-5. Loo TW, Bartlett MC, Clarke DM
Thapsigargin or curcumin does not promote maturation of processing mutants of the ABC transporters, CFTR, and P-glycoprotein.
Biochem Biophys Res Commun. 2004 Dec 10;325(2):580-5., [PMID:15530432]
Abstract [show]
Misprocessed plasma membrane proteins of CFTR and P-glycoprotein (P-gp) are retained in the endoplasmic reticulum (ER) by molecular chaperones. Depletion of the calcium stores in the ER by the SERCA calcium pump inhibitors thapsigargin or curcumin inhibits these interactions and allows the protein to be trafficked to the plasma membrane [Nat. Med. 8 (2002) 485; Science 304 (2004) 600]. We tested this hypothesis by treating various cell lines expressing misprocessed mutants of CFTR or P-gp with thapsigargin or curcumin. Conversion of the immature core-glycosylated protein to mature product was detected by immunoblot analysis of whole cell extracts. Mature product was not detected in any of the misprocessed mutants. By contrast, all misprocessed P-gp mutants were rescued by the chemical chaperone/drug substrate cyclosporin A in a dose-dependent manner. These results show that thapsigargin or curcumin is not effective in rescuing misprocessed mutants of P-gp and CFTR.
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No. Sentence Comment
70 Although the processing mutations (G251V, G300V, DY490, P709A, G722A, F804A, and P1194A) are located in different segments of P-gp, all the mutants could be rescued when expressed with drug substrates such as cyclosporin A.
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ABCB1 p.Pro709Ala 15530432:70:56
status: NEW90 We then compared the abilities of cyclosporin A, thapsigargin, and curcumin to induce maturation of P-gp processing mutants G251V, G300V, DY490, P709A, G722A, F804A, and P1194A.
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ABCB1 p.Pro709Ala 15530432:90:145
status: NEW[hide] Human P-glycoprotein contains a greasy ball-and-so... J Biol Chem. 2013 Jul 12;288(28):20326-33. doi: 10.1074/jbc.M113.484550. Epub 2013 Jun 3. Loo TW, Bartlett MC, Clarke DM
Human P-glycoprotein contains a greasy ball-and-socket joint at the second transmission interface.
J Biol Chem. 2013 Jul 12;288(28):20326-33. doi: 10.1074/jbc.M113.484550. Epub 2013 Jun 3., [PMID:23733192]
Abstract [show]
The P-glycoprotein drug pump protects us from toxins. Drug-binding sites in the transmembrane (TM) domains (TMDs) are connected to the nucleotide-binding domains (NBDs) by intracellular helices (IHs). TMD-NBD cross-talk is a key step in the transport mechanism because drug binding stimulates ATP hydrolysis followed by drug efflux. Here, we tested whether the IHs are critical for maturation and TMD-NBD coupling by characterizing the effects of mutations to the IH1 and IH2 interfaces. Although IH1 mutations had little effect, most mutations at the IH2-NBD2 interface inhibited maturation or activity. For example, the F1086A mutation at the IH2-NBD2 interface abolished drug-stimulated ATPase activity. The mutant F1086A, however, retained the ability to bind ATP and drug substrates. The mutant was defective in mediating ATP-dependent conformational changes in the TMDs because binding of ATP no longer promoted cross-linking between cysteines located at the extracellular ends of TM segments 6 and 12. Replacement of Phe-1086 (in NBD2) with hydrophobic but not charged residues yielded active mutants. The activity of the F1086A mutant could be restored when the nearby residue Ala-266 (in IH2) was replaced with aromatic residues. These results suggest that Ala-266/Phe-1086 lies in a hydrophobic IH2-NBD2 "ball-and-socket" joint.
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No. Sentence Comment
144 F, the P709A processing mutation wasintroducedintomutantF1086A.Mutantswereexpressedinthepresence (af9;) or absence (afa;) of verapamil (Ver), and whole cell extracts were subjected to immunoblot analysis.
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ABCB1 p.Pro709Ala 23733192:144:7
status: NEW157 Accordingly, the F1086A mutation was introduced into the P709A processing mutant.
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ABCB1 p.Pro709Ala 23733192:157:57
status: NEW158 The P709A mutant was selected because the mutation is located in the linker region that connects the two halves of P-gp and is outside the ATP-and drug-binding sites (Fig. 3, A and B).
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ABCB1 p.Pro709Ala 23733192:158:4
status: NEW159 Expression of mutant P709A/ F1086A yielded the 150-kDa immature form of P-gp as the major product (Fig. 3F).
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ABCB1 p.Pro709Ala 23733192:159:21
status: NEW