ABCMdb

PMID: 23835419

Loo TW, Bartlett MC, Clarke DM
Corrector VX-809 stabilizes the first transmembrane domain of CFTR.
Biochem Pharmacol. 2013 Sep 1;86(5):612-9. doi: 10.1016/j.bcp.2013.06.028. Epub 2013 Jul 5., [PubMed]

Sentences

No. Mutations Sentence Comment

29 ABCC7 p.Val510Asp We also report that V510D acts as a universal suppressor to rescue CFTR processing mutants. Login to comment 64 ABCC7 p.His1085Arg Arginine point mutations on the predicted aqueous face of TM6 (positions 338, 341, 344, 345, 348, 351) were introduced into processing mutants DF508, G232D, and H1085R. Login to comment 168 ABCC7 p.Leu346Arg ABCC7 p.Val345Arg ABCC7 p.Phe337Arg ABCC7 p.Ile344Arg Examples of the different effects of the arginines such as no effect (I344R), small reduction in maturation (V345R), large reduction in maturation (F337R), and no maturation (L346R) are shown in Fig. 4B. The TM6 arginine mutagenesis results were projected on a helical wheel (Fig. 4C). Login to comment 175 ABCC7 p.His1085Arg ABCC7 p.Val232Asp By contrast, other CFTR mutants defective in processing such as V232D and H1085R have half-lives similar to wild-type CFTR after rescue [14]. Login to comment 176 ABCC7 p.His1085Arg ABCC7 p.Val232Asp To test if other CFTR processing mutants could be rescued by TM6 mutations, arginine mutations were introduced at positions Ile338, Ser341, Ile344, Val345, Met348, and Thr351 of the V232D and H1085R processing mutants. Login to comment 177 ABCC7 p.His1085Arg ABCC7 p.Val232Asp None of the introduced arginines were found to promote maturation of V232D or H1085R. Login to comment 178 ABCC7 p.His1085Arg ABCC7 p.Val232Asp ABCC7 p.Ile344Arg ABCC7 p.Met348Arg Examples of typical results obtained with the I344R or M348R mutations introduced into V232D or H1085R are shown in Fig. 5B. Login to comment 179 ABCC7 p.His1085Arg ABCC7 p.Val232Asp It was possible that the processing mutations in the TMDs (V232D (TMD1) or H1085R (TMD2)) cannot be rescued by a direct rescue approach using suppressor mutations. Login to comment 180 ABCC7 p.His1085Arg ABCC7 p.Val232Asp ABCC7 p.Val232Asp ABCC7 p.Arg1070Trp ABCC7 p.Ile539Thr ABCC7 p.Val510Asp To test if the V232D or H1085R mutants could be rescued by suppressor mutations in other domains, suppressor mutations in NBD1 (I539T), the NBD1-TMD2 interface (V510D), or TMD2 (R1070W) (only V232D) locations were introduced into the mutants. Login to comment 182 ABCC7 p.Val510Asp All the mutants could be rescued by the V510D mutation (Fig. 5C). Login to comment 183 ABCC7 p.His1085Arg ABCC7 p.Val510Asp This result shows that the V510D and H1085R mutants could indeed be directly rescued by a suppressor mutation. Login to comment 184 ABCC7 p.Arg1070Trp ABCC7 p.Ile539Thr The I539T and R1070W mutations only rescued DF508 CFTR. Login to comment 185 ABCC7 p.Arg1070Trp ABCC7 p.Val510Asp We previously reported that the R1070W mutation also reduces the maturation efficiency of wild-type CFTR [32] while V510D does not [33]. Login to comment 186 ABCC7 p.Val510Asp The results suggest that the V510D is a 'universal suppressor` that is capable of rescuing CFTR mutants with processing mutations in multiple domains. Login to comment 196 ABCC7 p.His1085Arg ABCC7 p.Val232Asp RDR1 differs from VX-809 however, as we find that it does not rescue processing mutations in other domains such as V232D (TMD1) or H1085R (TMD2) (unpublished observations). Login to comment 204 ABCC7 p.Leu346Arg ABCC7 p.Val345Arg ABCC7 p.Phe337Arg ABCC7 p.Ile344Arg (B) Examples of immunoblots of wild-type CFTR and mutants I344R, V345R, F337R, and L346R showing the various effects of arginines introduced into TM6. Login to comment 220 ABCC7 p.His1085Arg ABCC7 p.Val232Asp None of the arginines introduced into CFTR processing mutants DF508, V232D, or H1085R promoted maturation. Login to comment 229 ABCC7 p.Thr351Arg ABCC7 p.Thr338Arg ABCC7 p.Ser341Arg We found that the maturation efficiency of predicted pore-lining arginine mutants T338R, S341R, Val345R, or T351R however, could be increased to wild-type levels (over 75% mature protein) if they were expressed in the presence of VX-809 (data not shown). Login to comment 232 ABCC7 p.Val510Asp Only the V510D suppressor mutation promotes maturation of mutants with processing mutations in multiple domains. Login to comment 236 ABCC7 p.His1085Arg ABCC7 p.Val232Asp ABCC7 p.Ile344Arg ABCC7 p.Met348Arg (B) Extracts of cells expressing wild-type CFTR or mutants V232D or H1085R with or without the I344R or M348R mutations were subjected to immunoblot analysis. Login to comment 237 ABCC7 p.His1085Arg ABCC7 p.Val232Asp ABCC7 p.Arg1070Trp ABCC7 p.Ile539Thr ABCC7 p.Val510Asp (C) Extracts of cells expressing processing mutants DF508, V232D, or H1085R with or without the V510D, I539T, or R1070W suppressor mutations were subjected to immunoblot analysis. Login to comment 249 ABCC7 p.Val510Asp VX-809 shows characteristics similar to the V510D suppressor that is located at the NBD1-ICL2 interface (Fig. 6A) as both can promote maturation of mutants with processing mutations in different domains. Login to comment 259 ABCC7 p.Val510Asp Finally, the studies suggest that V510D differs from many other suppressor mutations because it acts as a universal suppressor to rescue mutants with mutations in many domains. Login to comment