ABCMdb

ABCC7 p.Arg303Cys

None has been submitted yet.

Publications

PMID: 17043152 [PubMed] Aubin CN et al: "Positive charges at the intracellular mouth of the pore regulate anion conduction in the CFTR chloride channel."

No. Sentence Comment

119 However, modification of R303C is illustrated in Figs. 7 and 8. Login to comment
124 Similar rundown was also observed in R303C (Fig. 7, A and C; Fig. 8 A), however, the shape of the I-V curve changed during the rundown process, becoming more outwardly rectifying after addition of MTSES (Fig. 7, B and E; Fig. 9) and more inwardly rectifying after application of MTSET (Figs. 8 and 9). Login to comment
137 Data from the same patches as in A, recorded before (control) and 6 min after addition of MTSES, are scaled to show the development of outward rectification in R303C but not wild type. Login to comment
152 (A) Individual examples of the time course of MTSET-induced current rundown in wild type and R303C. Login to comment

PMID: 19466983 [PubMed] Li MS et al: "Cysteine-independent inhibition of the CFTR chloride channel by the cysteine-reactive reagent sodium (2-sulphonatoethyl) methanethiosulphonate."

No. Sentence Comment

103 This could be misinterpreted as being the result of charge deposition in the permeation pathway due to covalent modification of a cysteine side chain. For example, we previously showed that intracellular application of a low concentration of MTSES (200 mmol·L-1 ) led to outward rectification of the macroscopic current-voltage relationship in a CFTR mutant (R303C) but not wild-type CFTR, which we proposed was due to the electrostatic effects of the addition of a negative charge close to the inner mouth of the pore by covalent modification of the introduced cysteine side chain (St. Aubin and Linsdell 2006). Login to comment
104 The change in macroscopic current-voltage relationship shape observed in MTSES-modified R303C-CFTR is, however, similar to that resulting from voltage-dependent block by MTSES (Figure 1A). Login to comment
105 Nevertheless, it seems unlikely that open channel block contributed to the reported effects of MTSES on R303C-CFTR, since (i) qualitatively opposite effects were observed with positively charged MTSET, and (ii) these effects were observed at MTSES concentrations of only 200 mmol·L-1 , a concentration which does not result in significant current blockage (Figure 1). Login to comment

PMID: 25944907 [PubMed] El Hiani Y et al: "Functional Architecture of the Cytoplasmic Entrance to the Cystic Fibrosis Transmembrane Conductance Regulator Chloride Channel Pore."

No. Sentence Comment

45 Altering the side chain charge at this position (either by mutagenesis or by covalent modification of R303C by charged cysteine-reactive methanethiosulfonate (MTS) reagents) suggested that the positive charge at this position played a key role in attracting Clafa; ions electrostatically from the cytoplasm to the inner mouth of the pore (19). Login to comment
103 A-D, examples of modification of four different mutants (A, R303C, used in this study as a positive control; B, K190C; C, K370C; D, R1048C) by MTSES (left panels) or MTSET (right panels). Login to comment
109 Application of MTSES (200 òe;M) following channel activation with PKA and ATP never caused an increase in macroscopic current amplitude but decreased current amplitude in K190C, R248C, R251C, R303C, K370C, K946C, R975C, K1041C, and R1048C (Figs. 2 and 3). Login to comment
110 The effect of MTSET on these MTSES-sensitive mutants was to increase (K190C and R303C), decrease (R248C, K946C, K1041C, and R1048C), or have no effect (R251C, K370C, and R975C) on macroscopic current amplitude (Figs. 2 and 3). Login to comment
114 The effects of MTS modification of side chains within the ICLs could reflect changes in Clafa; conductance (as suggested previously for R303C (19)) or in open probability (as shown previously for K946C and R975C (11)) or a combination of the two. Login to comment
116 Results with R303C, K946C, and R975C, which as described above are expected to affect predominantly Clafa; conductance (R303C) or gating (K946C and R975C), suggest that use of PPi in this way can effectively separate effects on Clafa; conductance from those on gating. Login to comment
117 Thus, the effects of MTSES and MTSET on R303C were preserved following PPi treatment, consistent with a gating-independent effect on Clafa; conductance (Figs. 4 and 5). Login to comment
123 This implies that modification with positively charged MTSET caused an increase in Clafa; conductance in each of K190C, R248C, R303C, K370C, and R1048C, an effect that may potentially be masked by inhibitory effects on channel open probability in normally gating channels. Login to comment
132 Error bars represent the means afe; S.E. from three to five patches. Cytoplasmic Entrance to the CFTR Channel Pore JUNE 19, 2015ߦVOLUME 290ߦNUMBER 25 JOURNAL OF BIOLOGICAL CHEMISTRY 15859 rent amplitude in each of K190C, R248C, R303C, K370C, K1041C, and R1048C. Login to comment
141 Cytoplasmic Entrance to the CFTR Channel Pore 15860 JOURNAL OF BIOLOGICAL CHEMISTRY VOLUME 290ߦNUMBER 25ߦJUNE 19, 2015 at SEMMELWEIS UNIV OF MEDICINE on December 4, amplitudes in unmodified channels was Cys-less b; K946C b03; R975C b0e; K370C b0e; R251C b0e; K1041C b03; R248C b0e; R1048C b0e; R303C b0e; K190C (Fig. 7A). Login to comment
142 Among channels showing MTSES-sensitive current amplitudes, the order following modification was K1041C b0e; R1048C b0e; K370C b0e; R248C b0e; R303C b0e; K190C (Fig. 6, B and C, and 7B). Login to comment
155 Single channel recording indicated directly that for each of K190C, R248C, R303C, K370C, K1041C, and R1048C Clafa; conductance was reduced relative to Cys-less (Figs. 6 and 7A), Clafa; conductance was further reduced by modification by negatively charged MTSES (Figs. 6 and 7B), and Clafa; conductance was restored to near wild-type (Cys-less) values by modification by positively charged MTSET (Figs. 6 and 7C). Login to comment
166 In contrast, the effects of MTS modification of PPi-treated channels in K190C, R248C, R303C, K370C, and R1048C (Fig. 5) closely mirrored the charge-dependent effects of MTS modification on single channel current amplitude (Figs. 6 and 7). Login to comment
173 We believe that the functional importance of Lys-190, Arg-248, Arg-303, and Lys-370 is likely greater than that of Lys-1041 and Arg-1048 because of the greater reduction in single channel current amplitude following introduction of a negative charge by MTSES modification in K190C, R248C, R303C, and K370C FIGURE 6. Login to comment
181 Single channel current amplitude was very low in MTSES- modified K190C, R248C, R303C, and K370C channels (b0d;25% of Cys-less current amplitude; Figs. 6, B and C, and 7B), suggesting that most permeating Clafa; ions must pass close to these residues. Login to comment