ABCC7 p.Val510Thr
| Predicted by SNAP2: | A: N (82%), C: N (72%), D: N (57%), E: N (72%), F: N (72%), G: N (72%), H: N (66%), I: N (93%), K: N (82%), L: N (87%), M: N (87%), N: N (72%), P: N (66%), Q: N (82%), R: N (78%), S: N (72%), T: N (87%), W: D (66%), Y: N (78%), |
| 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, P: N, Q: N, R: N, S: N, T: N, W: N, Y: N, |
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[hide] Correctors promote maturation of cystic fibrosis t... J Biol Chem. 2007 Nov 16;282(46):33247-51. Epub 2007 Oct 2. Wang Y, Loo TW, Bartlett MC, Clarke DM
Correctors promote maturation of cystic fibrosis transmembrane conductance regulator (CFTR)-processing mutants by binding to the protein.
J Biol Chem. 2007 Nov 16;282(46):33247-51. Epub 2007 Oct 2., 2007-11-16 [PMID:17911111]
Abstract [show]
The most common cause of cystic fibrosis (CF) is defective folding of a cystic fibrosis transmembrane conductance regulator (CFTR) mutant lacking Phe(508) (DeltaF508). The DeltaF508 protein appears to be trapped in a prefolded state with incomplete packing of the transmembrane (TM) segments, a defect that can be repaired by expression in the presence of correctors such as corr-4a, VRT-325, and VRT-532. To determine whether the mechanism of correctors involves direct interactions with CFTR, our approach was to test whether correctors blocked disulfide cross-linking between cysteines introduced into the two halves of a Cys-less CFTR. Although replacement of the 18 endogenous cysteines of CFTR with Ser or Ala yields a Cys-less mutant that does not mature at 37 degrees C, we found that maturation could be restored if Val(510) was changed to Ala, Cys, Ser, Thr, Gly, Ala, or Asp. The V510D mutation also promoted maturation of DeltaF508 CFTR. The Cys-less/V510A mutant was used for subsequent cross-linking analysis as it yielded relatively high levels of mature protein that was functional in iodide efflux assays. We tested for cross-linking between cysteines introduced into TM6 and TM7 of Cys-less CFTR/V510A because cross-linking between TM6 and TM7 of P-glycoprotein, the sister protein of CFTR, was inhibited with the corrector VRT-325. Cys-less CFTR/V510A mutant containing cysteines at I340C(TM6) and S877C(TM7) could be cross-linked with a homobifunctional cross-linker. Correctors and the CFTR channel blocker benzbromarone, but not P-glycoprotein substrates, inhibited cross-linking of mutant I340C(TM6)/S877C(TM7). These results suggest that corrector molecules such as corr-4a interact directly with CFTR.
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No. Sentence Comment
67 Cys-less mutants in which residue Val510 was changed to Pro, Thr, Tyr, Gly, Ala, Ser, Leu, Asp, Phe, or Trp were constructed.
X
ABCC7 p.Val510Thr 17911111:67:34
status: NEW68 The mutants were expressed in HEK 293 cells at 37 °C, and whole cell extracts were subjected to immunoblot analysis. Fig. 2B shows that changing Val510 to Thr, Gly, Ala, Ser, or Asp promoted maturation of Cys-less CFTR.
X
ABCC7 p.Val510Thr 17911111:68:150
status: NEW[hide] The V510D suppressor mutation stabilizes DeltaF508... Biochemistry. 2010 Aug 3;49(30):6352-7. Loo TW, Bartlett MC, Clarke DM
The V510D suppressor mutation stabilizes DeltaF508-CFTR at the cell surface.
Biochemistry. 2010 Aug 3;49(30):6352-7., 2010-08-03 [PMID:20590134]
Abstract [show]
Deletion of Phe508 (DeltaF508) in the first nucleotide-binding domain (NBD1) of CFTR causes cystic fibrosis. The mutation severely reduces the stability and folding of the protein by disrupting interactions between NBD1 and the second transmembrane domain (TMD2). We found that replacement of Val510 with acidic residues (but not neutral or positive residues) promoted maturation of DeltaF508-CFTR with V510D more efficiently than V510E. Promotion of DeltaF508-CFTR maturation did not require NBD2 as introduction of V510D into a DeltaNBD2/DeltaF508-CFTR mutant restored maturation to levels similar to that of full-length protein. The V510D mutation increased the half-life of mature DeltaF508-CFTR at the cell surface by about 5-fold to resemble the half-life of wild-type CFTR. It was also observed that introduction of the V510R/R1070D mutations into DeltaF508-CFTR also promoted maturation whereas the V510D/R1070A mutations did not. We propose that the V510D mutation in NBD1 promotes maturation and stabilizes DeltaF508-CFTR at the cell surface through formation of a salt bridge with Arg1070 in TMD2.
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No. Sentence Comment
178 While introduction of V510D into Cys-less or ΔF508-CFTRs promoted maturation, the Cys-less mutant was different because its maturation could also be promoted by changing Val510 to Thr, Cys, Gly, Ala, or Ser.
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ABCC7 p.Val510Thr 20590134:178:176
status: NEW