ABCC7 p.Ser1141Arg
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PMID: 23865422
[PubMed]
Loo TW et al: "Bithiazole correctors rescue CFTR mutants by two different mechanisms."
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Sentence
Comment
17
VX-809 appears to rescue CFTR processing mutants through direct interactions with TMD1.12,18 Bithiazoles, however, appear to rescue CFTR processing mutants by a different mechanism because bithiazoles have an additive effect on maturation when used in combination with VX-809.15 Identification of the bithiazole rescue site in CFTR is controversial as there is evidence that these compounds bind to NBD218 or to the TMDs.9 Evidence that bithiazoles interact with the TMDs was that 4a inhibited cross-linking between cysteines introduced into TMD1 and TMD219 and that 4a appears to stabilize TMD2.20 In addition, it was found that bithiazoles enhanced core glycosylation of a truncation mutant that contained only the TMDs.19 By contrast, it was recently reported that bithiazoles must interact with NBD2 because ƊF508 CFTR missing NBD2 was not rescued with bithiazoles and in silico docking predicted the presence of a bithiazole-binding site in NBD2.18 To test whether rescue of other CFTR processing mutants with bithiazoles (see Figure 1 for structures) was mediated by the TMDs or NBD2, we tested if bithiazoles could rescue full-length or ƊNBD2 CFTR mutants that had processing mutations in the TMDs such as G126D in TM2,21 V232D in Received: July 3, 2013 Revised: July 17, 2013 Published: July 18, 2013 Rapid Report pubs.acs.org/biochemistry (c) 2013 American Chemical Society dx.doi.org/10.1021/bi4008758 | Biochemistry 2013, 52, 5161-5163 Terms of Use TM4,20 F337R in TM6,12 and S1141R in TM12 (see Figure 2A).
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ABCC7 p.Ser1141Arg 23865422:17:1499
status: NEW18 Mutants G126D and V232D are naturally occurring CF mutants, whereas F337R and S1141R mutants were constructed to map the orientation of the TM segments.12 The mutants were expressed for 18 h with or without VX-809 or the 4a, 4d, or 15Jf bithiazole correctors.
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ABCC7 p.Ser1141Arg 23865422:18:78
status: NEW20 Figure 2B shows that full-length and ƊNBD2 forms of G126D, V232D, and S1141R could be efficiently rescued with all the correctors such that the mature protein was the major product (Figure 2C,D).
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ABCC7 p.Ser1141Arg 23865422:20:75
status: NEW25 The second bithiazole rescue mechanism appears to involve the TMDs because removal of NBD2 had little effect on bithiazole rescue of mutants G126D, V232D, and S1141R and mutation F337R in TM6 inhibited rescue of full-length CFTR with bithiazoles.
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ABCC7 p.Ser1141Arg 23865422:25:159
status: NEW