ABCC7 p.Ser1118Ala
| ClinVar: |
c.3353C>T
,
p.Ser1118Phe
?
, not provided
c.3353C>G , p.Ser1118Cys ? , not provided |
| CF databases: |
c.3353C>G
,
p.Ser1118Cys
(CFTR1)
D
, The mutation was detected by multiplex heteroduplex analysis on the MDE gel matrix. It was found in one Canadian CBAVD patient (second mutation: [delta]F508).
c.3353C>T , p.Ser1118Phe (CFTR1) ? , CF patient. |
| Predicted by SNAP2: | A: N (87%), C: N (87%), D: D (63%), E: D (63%), F: D (53%), G: N (82%), H: D (53%), I: D (63%), K: D (66%), L: N (57%), M: D (63%), N: N (61%), P: N (53%), Q: D (53%), R: D (66%), T: N (82%), V: N (61%), W: D (75%), Y: D (63%), |
| Predicted by PROVEAN: | A: N, C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, T: N, V: N, W: D, Y: N, |
[switch to compact view]
Comments [show]
None has been submitted yet.
[hide] Relationship between anion binding and anion perme... J Physiol. 2001 Feb 15;531(Pt 1):51-66. Linsdell P
Relationship between anion binding and anion permeability revealed by mutagenesis within the cystic fibrosis transmembrane conductance regulator chloride channel pore.
J Physiol. 2001 Feb 15;531(Pt 1):51-66., 2001-02-15 [PMID:11179391]
Abstract [show]
1. Anion binding within the pores of wild-type and mutant cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels, expressed in two different mammalian cell lines, was assayed using patch clamp recording. Specifically, experiments measured both the conductance of different anions and the ability of other permeant anions to block Cl- permeation through the pore. 2. Under symmetrical ionic conditions, wild-type CFTR channels showed the conductance sequence Cl- > NO3- > Br- > or = formate > F- > SCN- congruent to ClO4-. 3. High SCN- conductance was not observed, nor was there an anomalous mole fraction effect of SCN- on conductance under the conditions used. Iodide currents could not be measured under symmetrical ionic conditions, but under bi-ionic conditions I- conductance appeared low. 4. Chloride currents through CFTR channels were blocked by low concentrations (10 mM) of SCN-, I- and ClO4-, implying relatively tight binding of these anions within the pore. 5. Two mutations in CFTR which alter the anion permeability sequence, F337S and T338A, also altered the anion conductance sequence. Furthermore, block by SCN-, I- and ClO4- were weakened in both mutants. Both these effects are consistent with altered anion binding within the pore. 6. The effects of mutations on anion permeability and relative anion conductance suggested that, for most anions, increased permeability was associated with increased conductance. This indicates that the CFTR channel pore does not achieve its anion selectivity by selective anion binding within the mutated region. Instead, it is suggested that entry of anions into the region around F337 and T338 facilitates their passage through the pore. In wild-type CFTR channels, anion entry into this crucial pore region is probably dominated by anion hydration energies.
Comments [show]
None has been submitted yet.
No. Sentence Comment
254 Interestingly, S1118 in TM11 has been suggested to occupy a position similar to that of T338 in TM6, and the mutations S1118A and S1118F cause small alterations in anion permeability (Zhang et al. 2000).
X
ABCC7 p.Ser1118Ala 11179391:254:119
status: NEW[hide] Novel residues lining the CFTR chloride channel po... J Membr Biol. 2009 Apr;228(3):151-64. Epub 2009 Apr 19. Fatehi M, Linsdell P
Novel residues lining the CFTR chloride channel pore identified by functional modification of introduced cysteines.
J Membr Biol. 2009 Apr;228(3):151-64. Epub 2009 Apr 19., [PMID:19381710]
Abstract [show]
Substituted cysteine accessibility mutagenesis (SCAM) has been used widely to identify pore-lining amino acid side chains in ion channel proteins. However, functional effects on permeation and gating can be difficult to separate, leading to uncertainty concerning the location of reactive cysteine side chains. We have combined SCAM with investigation of the charge-dependent effects of methanethiosulfonate (MTS) reagents on the functional permeation properties of cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channels. We find that cysteines substituted for seven out of 21 continuous amino acids in the eleventh and twelfth transmembrane (TM) regions can be modified by external application of positively charged [2-(trimethylammonium)ethyl] MTS bromide (MTSET) and negatively charged sodium [2-sulfonatoethyl] MTS (MTSES). Modification of these cysteines leads to changes in the open channel current-voltage relationship at both the macroscopic and single-channel current levels that reflect specific, charge-dependent effects on the rate of Cl(-) permeation through the channel from the external solution. This approach therefore identifies amino acid side chains that lie within the permeation pathway. Cysteine mutagenesis of pore-lining residues also affects intrapore anion binding and anion selectivity, giving more information regarding the roles of these residues. Our results demonstrate a straightforward method of screening for pore-lining amino acids in ion channels. We suggest that TM11 contributes to the CFTR pore and that the extracellular loop between TMs 11 and 12 lies close to the outer mouth of the pore.
Comments [show]
None has been submitted yet.
No. Sentence Comment
201 Previously, SCN- permeabil- ity was shown to be significantly decreased in S1118F but unaltered in S1118A (Zhang et al. 2000).
X
ABCC7 p.Ser1118Ala 19381710:201:99
status: NEW[hide] Novel pore-lining residues in CFTR that govern per... Neuron. 1994 Sep;13(3):623-34. McDonough S, Davidson N, Lester HA, McCarty NA
Novel pore-lining residues in CFTR that govern permeation and open-channel block.
Neuron. 1994 Sep;13(3):623-34., [PMID:7522483]
Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) is both a member of the ATP-binding cassette superfamily and a Cl(-)-selective ion channel. We investigated the permeation pathway of human CFTR with measurements on conduction and open-channel blockade by diphenylamine-2-carboxylic acid (DPC). We used site-directed mutagenesis and oocyte expression to locate residues in transmembrane domain (TM) 6 and TM 12 that contact DPC and control rectification and single-channel conductances. Thus, TM 12 and the previously investigated TM 6 line the CFTR pore. In each TM, residues in contact with DPC are separated by two turns of an alpha helix. The contributions of TM 6 and TM 12 to DPC block and Cl- permeation, however, are not equivalent. The resulting structural model for the conduction pathway may guide future studies of permeation in other Cl- channels and ATP-binding cassette transporters.
Comments [show]
None has been submitted yet.
No. Sentence Comment
78 Affinity and Voltage Dependence for Block of CFTR Variants by DPC Construct TM Ko( - 100) (PM) 0 I-V Relation n Properties Wild type Wild type low [Cl-], (10 mM) K335E 6 K335F 6 T338A 6 T339A 6 S341A 6 S341T 6 S1118A 11 T1134A 12 T1134F 12 S1141A 12 Triple 6,12 276 f 14 181 f 13" 303 -t 14 351 * 15' 220 * 14 284 * 47 1251 f 116a 530 f 80" 243 * 37 230 * 20 74 * 3" 220 * 13 325 * 26b 0.41 f 0.01 0.32 f 0.02" 0.42 f 0.01 0.42 f 0.02 0.36 f 0.02" 0.44 * 0.12 0.49 * 0.03" 0.35 f 0.09 0.40 f 0.02 0.35 * 0.02" 0.41 f 0.01 0.42 f 0.03 0.21 * O.Ol",b Linear, E,,, = -8 f 1 mV Ere\ = +48+2mV Inward rectification Linear Linear Linear Strong inward rectification Inward rectification Linear Linear Linear Linear Strong inward rectification Affinity for DPC was determined empirically at -100 mV, from whole-cell currents measured in the presence of 200 uM DPC (see Experimental Procedures).
X
ABCC7 p.Ser1118Ala 7522483:78:210
status: NEW[hide] Interaction between permeation and gating in a put... Biophys J. 2000 Jul;79(1):298-313. Zhang ZR, McDonough SI, McCarty NA
Interaction between permeation and gating in a putative pore domain mutant in the cystic fibrosis transmembrane conductance regulator.
Biophys J. 2000 Jul;79(1):298-313., [PMID:10866956]
Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel with distinctive kinetics. At the whole-cell level, CFTR currents in response to voltage steps are time independent for wild type and for the many mutants reported so far. Single channels open for periods lasting up to tens of seconds; the openings are interrupted by brief closures at hyperpolarized, but not depolarized, potentials. Here we report a serine-to-phenylalanine mutation (S1118F) in the 11th transmembrane domain that confers voltage-dependent, single-exponential current relaxations and moderate inward rectification of the macroscopic currents upon expression in Xenopus oocytes. At steady state, the S1118F-CFTR single-channel conductance rectifies, corresponding to the whole-cell rectification. In addition, the open-channel burst duration is decreased 10-fold compared with wild-type channels. S1118F-CFTR currents are blocked in a voltage-dependent manner by diphenylamine-2-carboxylate (DPC); the affinity of S1118F-CFTR for DPC is similar to that of the wild-type channel, but blockade exhibits moderately reduced voltage dependence. Selectivity of the channel to a range of anions is also affected by this mutation. Furthermore, the permeation properties change during the relaxations, which suggests that there is an interaction between gating and permeation in this mutant. The existence of a mutation that confers voltage dependence upon CFTR currents and that changes kinetics and permeation properties of the channel suggests a functional role for the 11th transmembrane domain in the pore in the wild-type channel.
Comments [show]
None has been submitted yet.
No. Sentence Comment
33 Preparation of oocytes and cRNA CFTR was subcloned into the pALTER vector (Promega), and the S1118F, S1118A, and S1118F/F1111S mutations were made using the Promega Altered Sites protocol (McDonough et al., 1994).
X
ABCC7 p.Ser1118Ala 10866956:33:101
status: NEW125 These relaxations are not seen in S1118A channels (not shown).
X
ABCC7 p.Ser1118Ala 10866956:125:34
status: NEW128 In addition, mutation of S1118 to alanine (S1118A-CFTR) did not cause relaxations.
X
ABCC7 p.Ser1118Ala 10866956:128:43
status: NEW180 Instead, currents in oocytes expressing WT-, S1118F-, or S1118A-CFTR channels were elicited by stepping for 75 ms from the holding potential of afa;30 mV to a series of test potentials between afa;140 and af9;80 mV in af9;20 mV increments.
X
ABCC7 p.Ser1118Ala 10866956:180:57
status: NEW206 S1118A-CFTR channels did not indicate time dependence with this protocol (not shown).
X
ABCC7 p.Ser1118Ala 10866956:206:0
status: NEW235 Data are shown for both instantaneous currents and steady-state currents for WT and S1118F-CFTR (Fig. 8, A and B) or S1118A-CFTR (Fig. 8, C and D).
X
ABCC7 p.Ser1118Ala 10866956:235:117
status: NEW236 In Clafa; -containing solutions, before anion substitutions were made, there was a significant difference (p afd; 0.047) between instantaneous and steady-state reversal potentials in S1118F-CFTR (Table 2) compared to the WT (Table 1), but not in S1118A-CFTR.
X
ABCC7 p.Ser1118Ala 10866956:236:252
status: NEW239 The ability of the large anions (acetate, gluconate, glutamate, and isethionate) to gain access to the pore is altered by mutations S1118A and S1118F, as indicated by mild to significant changes in relative permeabilities for these anions compared to that in WT channels.
X
ABCC7 p.Ser1118Ala 10866956:239:132
status: NEW242 S1118A-CFTR exhibited reduced relative permeabilities for all of the large anions and for perchlorate.
X
ABCC7 p.Ser1118Ala 10866956:242:0
status: NEW250 Relative conductances were generally less affected in S1118A-CFTR than in S1118F-CFTR.
X
ABCC7 p.Ser1118Ala 10866956:250:54
status: NEW251 In contrast, mutation S1118A had the greatest effects on PX/PCl relationships, particularly for the large polyatomic anions (Fig. 8, C and D).
X
ABCC7 p.Ser1118Ala 10866956:251:22
status: NEW252 FIGURE 8 Selectivity data for WT CFTR as compared to S1118F-CFTR (A and B) and S1118A-CFTR (C and D).
X
ABCC7 p.Ser1118Ala 10866956:252:79
status: NEW260 &#a7; p b0d; 0.01 for S1118F-CFTR or p afd; 0.02 for S1118A-CFTR.
X
ABCC7 p.Ser1118Ala 10866956:260:59
status: NEW263 Nor does relative permeability for S1118F-CFTR (Fig. 8 A) or S1118A-CFTR (Fig. 8 C) show any time dependence.
X
ABCC7 p.Ser1118Ala 10866956:263:61
status: NEW267 As shown in Fig. 8 D, there was also a statistically significant time dependence of relative conductance to perchlorate for S1118A-CFTR (p afd; 0.02).
X
ABCC7 p.Ser1118Ala 10866956:267:124
status: NEW284 TABLE 2 Selectivity in S1118F-CFTR and S1118A-CFTR Ion S1118F S1118A Erev (mV) PX/PCl GX/GCl Erev (mV) PX/PCl GX/GCl SCN afa;40.97 afe; 1.20* 1.84 afe; 0.08* 0.57 afe; 0.02* afa;56.44 afe; 0.93 2.59 afe; 0.09 0.20 afe; 0.01 NO3 afa;32.83 afe; 1.69 1.30 afe; 0.06 0.95 afe; 0.02 afa;37.35 afe; 0.87 1.21 afe; 0.04 0.88 afe; 0.01 Br afa;28.28 afe; 1.32 1.07 afe; 0.03 0.88 afe; 0.03* afa;34.53 afe; 0.85 1.12 afe; 0.02 0.77 afe; 0.01 Cl afa;26.14 afe; 1.59* 1.0 1.0 afa;30.63 afe; 0.64 1.0 1.0 I afa;8.46 afe; 1.14 0.52 afe; 0.03* 0.38 afe; 0.03* afa;10.35 afe; 1.26 0.39 afe; 0.01 0.27 afe; 0.05 Acetate 39.64 afe; 1.77* 0.05 afe; 0.01* 0.12 afe; 0.01* 23.24 afe; 1.83* 0.09 afe; 0.01* 0.50 afe; 0.01* Glutamate 23.93 afe; 3.61* 0.16 afe; 0.01* 0.23 afe; 0.01* 19.59 afe; 1.07* 0.09 afe; 0.01* 0.49 afe; 0.01* 0.32 afe; 0.01I * Isethionate 20.24 afe; 3.62* 0.14 afe; 0.03 0.25 afe; 0.02* 23.71 afe; 0.99* 0.09 afe; 0.01* 0.48 afe; 0.01 ClO4 afa;6.42 afe; 1.57* 0.42 afe; 0.02* 0.18 afe; 0.01 27.29 afe; 1.36* 0.06 afe; 0.01* 0.12 afe; 0.01* 0.14 afe; 0.01I * Gluconate 28.26 afe; 3.29* 0.12 afe; 0.02 0.20 afe; 0.01* 20.03 afe; 1.04* 0.10 afe; 0.01* 0.50 afe; 0.01* 0.27 afe; 0.01I * Ions are listed in the same order as in Table 1.
X
ABCC7 p.Ser1118Ala 10866956:284:39
status: NEWX
ABCC7 p.Ser1118Ala 10866956:284:62
status: NEW345 Similarly, S1118A did not affect block by DPC (McDonough et al., 1994).
X
ABCC7 p.Ser1118Ala 10866956:345:11
status: NEW346 However, both S1118A-CFTR and S1118F-CFTR altered the selectivity behavior of the pore, suggesting that this position may contribute to the pore walls.
X
ABCC7 p.Ser1118Ala 10866956:346:14
status: NEW348 In contrast, mutation S1118A exhibited the greatest effects on relative permeabilities, especially for the large anions.
X
ABCC7 p.Ser1118Ala 10866956:348:22
status: NEW377 Similarly, the current relaxations are not due to disruption of a putative interaction between S1118 and another amino acid, because no relaxations were observed for S1118A-CFTR.
X
ABCC7 p.Ser1118Ala 10866956:377:166
status: NEW[hide] Relative contribution of different transmembrane s... Pflugers Arch. 2014 Mar;466(3):477-90. doi: 10.1007/s00424-013-1317-x. Epub 2013 Aug 20. Wang W, El Hiani Y, Rubaiy HN, Linsdell P
Relative contribution of different transmembrane segments to the CFTR chloride channel pore.
Pflugers Arch. 2014 Mar;466(3):477-90. doi: 10.1007/s00424-013-1317-x. Epub 2013 Aug 20., [PMID:23955087]
Abstract [show]
The membrane-spanning part of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel comprises 12 transmembrane (TM) alpha-helices, arranged in 2 symmetrical groups of 6. However, those TMs that line the channel pore are not completely defined. We used patch clamp recording to compare the accessibility of cysteine-reactive reagents to cysteines introduced into different TMs. Several residues in TM11 were accessible to extracellular and/or intracellular cysteine reactive reagents; however, no reactive cysteines were identified in TMs 5 or 11. Two accessible residues in TM11 (T1115C and S1118C) were found to be more readily modified from the extracellular solution in closed channels, but more readily modified from the intracellular solution in open channels, as previously reported for T338C in TM6. However, the effects of mutagenesis at S1118 (TM11) on a range of pore functional properties were relatively minor compared to the large effects of mutagenesis at T338 (TM6). Our results suggest that the CFTR pore is lined by TM11 but not by TM5 or TM7. Comparison with previous works therefore suggests that the pore is lined by TMs 1, 6, 11, and 12, suggesting that the structure of the open channel pore is asymmetric in terms of the contributions of different TMs. Although TMs 6 and 11 appear to undergo similar conformational changes during channel opening and closing, the influence of these two TMs on the functional properties of the narrowest region of the pore is clearly unequal.
Comments [show]
None has been submitted yet.
No. Sentence Comment
150 In addition, possible additive effects of reducing the side chain volumes of these two nearby residues was investigated using a T338A/S1118A double mutant.
X
ABCC7 p.Ser1118Ala 23955087:150:134
status: NEW153 In contrast, S1118A had no effect on conductance, while S1118Q and S1118V were associated with Fig. 7 Thiocyanate permeability of mutants.
X
ABCC7 p.Ser1118Ala 23955087:153:13
status: NEW155 The depolarizing (rightward) shift in the current reversal potential indicates an increased PSCN/PCl in the T338A/S1118A double mutant.
X
ABCC7 p.Ser1118Ala 23955087:155:114
status: NEW158 The hypolarizing (leftward) shift in the current reversal potential indicates an increased Pacetate/PCl in the T338A/S1118A double mutant.
X
ABCC7 p.Ser1118Ala 23955087:158:117
status: NEW163 The double mutant T338A/S1118A had a similarly elevated conductance that was not significantly different from that of T338A alone (P>0.75; Fig. 5).
X
ABCC7 p.Ser1118Ala 23955087:163:24
status: NEW167 Block by intracellular Au(CN)2 - was also significantly weakened in S1118A, S1118T, and T1115A compared to wild type, especially at hyperpolarized membrane potentials (Fig. 6); however, no apparent "U"-shape to the fractional current-voltage relationship was observed (Fig. 6b).
X
ABCC7 p.Ser1118Ala 23955087:167:68
status: NEW168 Interestingly, block of the T338A/S1118A double mutant was slightly weaker than for T338A alone (Fig. 6c, d), suggesting that these two mutations might have additive effects on Au(CN)2 - binding in the pore.
X
ABCC7 p.Ser1118Ala 23955087:168:34
status: NEW180 As proposed previously for TM6 residue T338 [42], the channel is shown as being in an "outward facing" configuration when closed (with T1115 and S1118 accessible from the outside), and switching to an "inward facing" configuration on opening (with T1115 and S1118 accessible from the inside) S1118A and T1115A, although this increase was much less than that observed in T338A (Fig. 7b).
X
ABCC7 p.Ser1118Ala 23955087:180:294
status: NEW181 Interestingly, SCN- permeability was further increased in the T338A/S1118A double mutant (Fig. 7).
X
ABCC7 p.Ser1118Ala 23955087:181:68
status: NEW183 Acetate permeability was slightly increased in S1118A and T1115A, but not significantly changed in S1118Q or S1118V (Fig. 8b).
X
ABCC7 p.Ser1118Ala 23955087:183:47
status: NEW184 Again, the increase in acetate permeability seen in T338A was significantly augmented in the T338A/S1118A mutation (Fig. 8), suggesting an additive effect of these two mutations on organic anion permeability.
X
ABCC7 p.Ser1118Ala 23955087:184:99
status: NEW207 The effects of the S1118A mutation on permeant anion (Au(CN)2 - ) binding (Fig. 6), permeability of the lyotropic SCN- anion (Fig. 7), and permeability of the organic acetate anion (Fig. 8) were qualitatively similar to, but generally smaller than, those of T338A, and in fact similar effects were seen in T1115A.
X
ABCC7 p.Ser1118Ala 23955087:207:19
status: NEW208 Neither S1118A nor T1115A significantly altered single channel conductance, although introduction of larger amino acid side chains in S1118Q and S1118V led to very small decreases in conductance (Fig. 5).
X
ABCC7 p.Ser1118Ala 23955087:208:8
status: NEW211 Reduction of side chain volume in S1118A and T1115A, like T338A, led to an increase in the relative permeability of the small organic anion acetate, consistent with an increase in the apparent diameter of the narrowest region of the pore [25, 26]; however, introduction of side chains with larger volume (S1118Q, S1118V) did not lead to a decrease in acetate permeability (Fig. 8).
X
ABCC7 p.Ser1118Ala 23955087:211:34
status: NEW214 Most striking here were a significantly increased permeability of the T338A/S1118A double mutant both to SCN- (Fig. 7) and to acetate (Fig. 8).
X
ABCC7 p.Ser1118Ala 23955087:214:76
status: NEW215 Permeability of small lyotropic anions like SCN- might be influenced by interactions throughout the pore [18, 38] or might be determined predominantly at a localized "selectivity filter" [18, 24] and so the apparently additive effects of the T338A and S1118A mutations is difficult to interpret in terms of the relative roles or locations of these two residues.
X
ABCC7 p.Ser1118Ala 23955087:215:252
status: NEW216 Permeability of large anions such as acetate is thought to be determined predominantly by steric factors at the narrowest part of the pore [25], and so the increase in acetate permeability in T338A/S1118A compared to either mutation alone might be considered evidence that these two mutations impact the dimensions of a common, narrow region of the pore.
X
ABCC7 p.Ser1118Ala 23955087:216:198
status: NEW217 One possible reason contributing to the minor functional effects observed in these experiments is that S1118A (and T1115A) might be considered relatively conservative mutations leading to only small changes in amino acid side chain volume.
X
ABCC7 p.Ser1118Ala 23955087:217:103
status: NEW219 Previously, the S1118C mutation was shown to decrease conductance at positive voltages, leading to inward rectification of both the single channel and macroscopic current-voltage relationships [10], and although this would be considered a very conservative mutation (one oxygen atom replaced by sulfur) this effect was not reproduced in S1118A, S1118Q or S1118 (Fig. 5).
X
ABCC7 p.Ser1118Ala 23955087:219:337
status: NEW