ABCMdb

ABCC7 p.Arg117Ala

ClinVar:	c.350G>C , p.Arg117Pro ? , not provided c.349C>G , p.Arg117Gly ? , not provided c.350G>T , p.Arg117Leu ? , not provided c.349C>T , p.Arg117Cys D , Pathogenic c.350G>A , p.Arg117His D , Pathogenic
CF databases:	c.350G>A , p.Arg117His ? , Varying clinical consequence ; CFTR1: c.349C>T , p.Arg117Cys D , CF-causing ; CFTR1: The haplotype is 2-1-1-2 (XV2c-KM19-D9-J44) with seven GATT repeats. The mutation creates a new Bsml site. c.349C>G , p.Arg117Gly (CFTR1) ? , Was reported previously in one study of CBAVD. R117G/UND 7T/9T (Daudin et al., Fertility and Sterility, 74:1164-1174, 2000). c.350G>C , p.Arg117Pro (CFTR1) ? , A new missense mutation was found in exon 4 : R 117 P. The mutation was detected by DGGE analysis and identified by remplacement of an arginine residue by a proline at codon 117. The mutation creates new MnlI and NlaIV sites. The mutation was identified in one french CF chromosome. The patient has a mild lung disease and is sufficient pancreatic. c.350G>T , p.Arg117Leu (CFTR1) ? , This mutation was identified by DGGE and direct sequencing and was identified on one CF chromosome of Italian origin.
Predicted by SNAP2:	A: D (91%), C: D (63%), D: D (95%), E: D (95%), F: D (91%), G: D (95%), H: N (53%), I: D (85%), K: D (95%), L: D (63%), M: D (85%), N: D (95%), P: D (66%), Q: D (95%), S: D (95%), T: D (95%), V: D (91%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: N, C: D, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, S: N, T: N, V: N, W: N, Y: N,

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Publications
[hide] Three charged amino acids in extracellular loop 1 ... J Gen Physiol. 2014 Aug;144(2):159-79. doi: 10.1085/jgp.201311122. Epub 2014 Jul 14. Cui G, Rahman KS, Infield DT, Kuang C, Prince CZ, McCarty NA
Three charged amino acids in extracellular loop 1 are involved in maintaining the outer pore architecture of CFTR.
J Gen Physiol. 2014 Aug;144(2):159-79. doi: 10.1085/jgp.201311122. Epub 2014 Jul 14., [PMID:25024266]

Abstract [show]
The cystic fibrosis (CF) transmembrane conductance regulator (CFTR) bears six extracellular loops (ECL1-6); ECL1 is the site of several mutations associated with CF. Mutation R117H has been reported to reduce current amplitude, whereas D110H, E116K, and R117C/L/P may impair channel stability. We hypothesized that these amino acids might not be directly involved in ion conduction and permeation but may contribute to stabilizing the outer vestibule architecture in CFTR. We used cRNA injected oocytes combined with electrophysiological techniques to test this hypothesis. Mutants bearing cysteine at these sites were not functionally modified by extracellular MTS reagents and were blocked by GlyH-101 similarly to WT-CFTR. These results suggest that these three residues do not contribute directly to permeation in CFTR. In contrast, mutants D110R-, E116R-, and R117A-CFTR exhibited instability of the open state and significantly shortened burst duration compared with WT-CFTR and failed to be locked into the open state by AMP-PNP (adenosine 5'-(beta,gamma-imido) triphosphate); charge-retaining mutants showed mainly the full open state with comparably longer open burst duration. These interactions suggest that these ECL1 residues might be involved in maintaining the outer pore architecture of CFTR. A CFTR homology model suggested that E116 interacts with R104 in both the closed and open states, D110 interacts with K892 in the fully closed state, and R117 interacts with E1126 in the open state. These interactions were confirmed experimentally. The results suggest that D110, E116, and R117 may contribute to stabilizing the architecture of the outer pore of CFTR by interactions with other charged residues.

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20 In contrast, mutants D110R-, E116R-, and R117A-CFTR exhibited instability of the open state and significantly shortened burst duration compared with WT-CFTR and failed to be locked into the open state by AMP-PNP (adenosine 5&#e039;-(&#e062;,&#e067;-imido) triphosphate); charge-retaining mutants showed mainly the full open state with comparably longer open burst duration. Login to comment
74 Online supplemental material Fig. S1 illustrates representative single-channel current traces of D110R-, E116R-, and R117A-CFTR with a larger time scale (b) whether and how they contribute to maintaining open pore architecture; and (c) whether ECL1 moves during the CFTR gating cycle. Login to comment
97 Opening rates for WTand R104C/ E116C-CFTR were measured as previously described except that R117A-CFTR were significantly lower than WT-CFTR (Fig. 2 D). Login to comment
101 Given the instability of D110R-, E116R-, and R117A-CFTR single-channel openings, we asked whether AMP-PNP would lock these mutants into a stable open state. Login to comment
103 In contrast, AMP-PNP did not affect mean burst duration or single-channel amplitude of R117A-CFTR but did increase the apparent open probability (P < 0.05; Fig. 3). Login to comment
115 Fig. S3 shows representative I-V curves of D110R-, E116R-, and R117A-CFTR recorded in symmetrical 150 mM Cl&#e032; solution with the inside-out macropatch technique. Login to comment
124 To probe the potential mechanisms by which mutation of these charged residues leads to CF, we first recorded the single-channel behavior of a series of CFTR channel mutants bearing a single mutation at one of the six charged sites (D110R, D112R, K114D, E115R, E116R, or R117A). Login to comment
129 Unlike WT-CFTR, which opens mainly to the full open state(f)withsubconductancestatesasrareevents,D110R-, E116R-, and R117A-CFTR exhibited multiple open states, including subconductance state 1 (s1), subconductance state 2 (s2), and the f state (Fig. S1). Login to comment
133 The exception was K114D-CFTR, which exhibited mean burst duration significantly shorter than that of WT-CFTR, but much longer than that of D110R-, E116R-, and R117A-CFTR. Login to comment
145 (A) Representative single-channel current traces and their all-points histograms for WT-, D110R-, D112R-, K114D-, E115R-, E116R-, and R117A-CFTR from inside-out membrane patches excised from Xenopus oocytes, with symmetrical 150 mM Cl&#e032; solution in the presence of 1 mM MgATP and 50 U/ml PKA. Login to comment
149 (B and C) Single-channel amplitudes of the full open state (B) and mean burst durations (C) of WT-, D110R-, D112R-, K114D-, E115R-, E116R-, and R117A-CFTR. Login to comment
150 (D) Apparent open probability of WT-, D110R-, E116R-, and R117A-CFTR. Login to comment
154 ECL1 mutations shift the reversal potential in macroscopic currents To further verify that these ECL1 amino acids do not strongly or directly affect ion conduction and permeation, we compared the reversal potentials (Vrev) of D110R-, K114D-, E116R-, and R117A-CFTR with WT-CFTR and with the R334A mutant, which has been shown to have a profound effect on Vrev compared with WT-CFTR, consistent with the role of R334 in providing charge in the outer mouth of the open channel. Login to comment
156 E116R- and R117A-CFTR exhibited significantly right-shifted reversal potentials compared with WT-CFTR, but the effects were not as large as for R334A-CFTR. Login to comment
160 Of the ECL1 mutants we examined, the rectification ratios for D110R-, K114D-, and R117A-CFTR were similar to WT-CFTR (Fig. 6), whereas E116R-CFTR showed significantly reduced outward rectification. Login to comment
161 We also examined the I-V relationship of D110R-, E116R-, and R117A-CFTR with the inside-out macropatch technique in symmetrical that the charged amino acids in ECL1 might be involved in establishing the appropriate architecture for GlyH-101 binding and function. Login to comment
172 Figure 3.ߓ R117A-CFTR failed to be locked into a stable open state by AMP-PNP. Login to comment
173 R117A-CFTR was activated with 1 mM Mg-ATP and PKA and recorded under control conditions with ATP + PKA (&#e032;AMP-PNP), followed by addition of 2.75 mM AMP-PNP (+AMP-PNP). Login to comment
176 AMP-PNP had no effect on mean burst duration or single-channel amplitude but significantly increased apparent open probability of R117A-CFTR (n = 4). Login to comment
187 Under these conditions, E116R-CFTR exhibited slight inward rectification, but both D110R- and R117A-CFTR exhibited linear I-V relationships like that of WT-CFTR. Login to comment
206 All three mutants exhibited very brief openings to the s1, s2, and f states, with mean burst durations significantly lower than that of WT-CFTR (P < 0.001; Fig. 8 B) and R117A-CFTR (Fig. 2 C), but not different from D110R-CFTR and E116R-CFTR (Fig. 2 C). Login to comment
213 was less marked when R117K- and R117A-CFTR were compared (P < 0.05; Fig. 7, C and E). Login to comment
224 Tab l e 1 Reversal potentials of WT-CFTR and mutants in ND96 bath solution CFTR n Vrev mV WT 14 &#e032;27.75 &#b1; 0.78 R334A 6 &#e032;12.15 &#b1; 1.64a R117A 6 &#e032;22.51 &#b1; 0.85a E116R 5 &#e032;21.45 &#b1; 1.14a K114D 5 &#e032;24.68 &#b1; 3.22 D110R 5 &#e032;27.64 &#b1; 3.29 R104E 5 &#e032;21.15 &#b1; 1.08a R899C 4 &#e032;25.30 &#b1; 3.94 D891C 6 &#e032;25.81 &#b1; 2.44 K892E 5 &#e032;23.70 &#b1; 3.62 E1124R 5 &#e032;18.32 &#b1; 0.43a E1126R 5 &#e032;20.67 &#b1; 3.16b R117E/E1126R 6 &#e032;23.06 &#b1; 1.37b R104E/E116R 6 &#e032;27.17 &#b1; 1.08 Values are mean &#b1; SEM. Login to comment
246 (A-C) Representative single-channel currents of D110R- and D110E- (A), E116R- and E116D- (B), and R117A- and R117K-CFTR (C) recorded under the same conditions as Fig. 2 A. Login to comment
248 (D) Mean single-channel amplitude of WT-, D110R-, D110E-, E116R-, E116D-, R117A-, and R117K-CFTR. Login to comment
250 (E) Mean burst duration of WT-, D110R-, D110E-, E116R-, E116D-, R117A-, and R117K-CFTR. Login to comment
251 #, P < 0.001 indicates differences between D110R- and D110E-CFTR or E116R- and E116D-CFTR; *, P < 0.05 indicates differences between R117A- and R117K-CFTR. Login to comment
406 R117E/E1126R-CFTR opened to a full open state much more often compared with R117A-CFTR (Fig. 2). Login to comment
408 The mean burst duration of R117E/E1126R-CFTR was significantly longer than that of R117A- and R117C-CFTR. Login to comment
423 As shown here, mean burst durations of charge-retaining mutants D110E-, E116D-, and R117K-CFTR are significantly longer than their related charge-reversing or charge-destroying mutants D110R-, E116R-, and R117A-CFTR but distinctly shorter than that of WT-CFTR (Fig. 7). Login to comment