ABCMdb

ABCC7 p.Arg347Ile

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Publications

PMID: 15537638 [PubMed] Choi MY et al: "Destabilization of the transmembrane domain induces misfolding in a phenotypic mutant of cystic fibrosis transmembrane conductance regulator."

No. Sentence Comment

4 Furthermore, a second site mutation (R347I) that restores in vitro membrane insertion and folding of the TM5/6-L346P peptide also rescues the folding and cell surface chloride channel function of full-length L346P CFTR. Login to comment
60 A, wild type sequence; B, TM5/6-L346P; C, TM5/6-R347P; and D, TM5/6-L346P-R347I. Login to comment
116 WT, L346P, R347P, L346P/R347I, and R347H CFTR expression was assayed by immunoblotting, using the mouse monoclonal anti-HA Ab. Login to comment
146 Consideration of amino acid replacements in the vicinity of the L346P mutation identified a second site mutation (R347I) that restored the hydrophobicity of the TM6 L346P-containing segment to the threshold level that ensured membrane insertion according to TM Finder (Fig. 1D) (26). Login to comment
147 The L346P/R347I single spanning TM6 peptide was first synthesized, and analysis of its CD spectrum confirmed that this mutation restored the ␣-helical content of this TM6 double mutant to its WT counterpart (Fig. 4A). Login to comment
148 We then assessed whether the R347I mutation could restore hairpin formation of the TM5/6-L346P polypeptide by the FRET assay. Login to comment
149 Using a TM5/6-L346P/R347I peptide in which a Trp residue was inserted near the C terminus (Table I), and in which the N terminus was labeled with a dansyl group, we found that the donor fluorescence quench in the double mutant was now similar to that of the WT TM5/6 (Fig. 4B). Login to comment
152 Immunoblot analysis demonstrated the appearance of the complex-glycosylated L346P/R347I CFTR in both transiently transfected COS-1 and stably transfected BHK cells, whereas no detectable amount of L346P CFTR was present (Figs. Login to comment
160 A, CD spectra of TM6-WT and TM6-L346P/R347I in LPC micelles. B, Trp fluorescence spectra for the unlabeled and labeled TM5/ 6-WT and TM5/6-L346P/R347I peptides in LPC micelles. FRET measurements were performed using peptides labeled with dansyl chloride as the acceptor fluorophore with the Trp residue in TM6 serving as a donor fluorophore. Login to comment
186 B, cAMP-stimulated iodide efflux of BHK cells expressing wild-type (wt), L346P, or L346P/ R347I CFTR. Login to comment
200 The partial reversion of the L346P CFTR processing defect by a second site mutation (R347I) (Fig. 3B), which restores full-length TM6 insertion potential (Fig. 1D), suggests that segment hydrophobicity is prominent among the factors that play determining roles in the post-translational folding of CFTR. Login to comment
212 Note that this salt bridge would similarly be abolished in the L346P/R347I mutant, perhaps explaining, in part, why this "rescue mutant" is not fully functional. Login to comment

PMID: 18193900 [PubMed] Cheung JC et al: "Misfolding of the cystic fibrosis transmembrane conductance regulator and disease."

No. Sentence Comment

115 WT, L346P, R347P, L346P/R347I, and R347H CFTR expression was assayed by immunoblotting, using the mouse monoclonal anti-HA Ab. Equal loading of proteins was verified by visualizing the Na+/K+-ATPase (lower panel). Login to comment
138 The defect could be rescued in part by restoring hydrophobicity to TM6 via the double mutant L346P/R347I (Figure 4B). Login to comment