ABCMdb

ABCC7 p.Ser341Glu

ClinVar:	c.1021T>C , p.Ser341Pro D , Pathogenic
CF databases:	c.1021T>C , p.Ser341Pro D , CF-causing ; CFTR1: This homozygous mutation was identified in two sister siblings with CF.
Predicted by SNAP2:	A: D (71%), C: D (80%), D: D (91%), E: D (85%), F: D (85%), G: D (71%), H: D (85%), I: D (85%), K: D (85%), L: D (91%), M: D (85%), N: D (75%), P: D (91%), Q: D (80%), R: D (91%), T: D (53%), V: D (85%), W: D (85%), Y: D (85%),
Predicted by PROVEAN:	A: N, C: D, D: D, E: D, F: D, G: D, H: D, I: D, K: D, L: D, M: D, N: N, P: D, Q: D, R: D, T: N, V: D, W: D, Y: D,

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[hide] Identification of a region of strong discriminatio... Am J Physiol Lung Cell Mol Physiol. 2001 Oct;281(4):L852-67. McCarty NA, Zhang ZR
Identification of a region of strong discrimination in the pore of CFTR.
Am J Physiol Lung Cell Mol Physiol. 2001 Oct;281(4):L852-67., [PMID:11557589]

Abstract [show]
The variety of methods used to identify the structural determinants of anion selectivity in the cystic fibrosis transmembrane conductance regulator Cl(-) channel has made it difficult to assemble the data into a coherent framework that describes the three-dimensional structure of the pore. Here, we compare the relative importance of sites previously studied and identify new sites that contribute strongly to anion selectivity. We studied Cl(-) and substitute anions in oocytes expressing wild-type cystic fibrosis transmembrane conductance regulator or 12-pore-domain mutants to determine relative permeability and relative conductance for 9 monovalent anions and 1 divalent anion. The data indicate that the region of strong discrimination resides between T338 and S341 in transmembrane 6, where mutations affected selectivity between Cl(-) and both large and small anions. Mutations further toward the extracellular end of the pore only strongly affected selectivity between Cl(-) and larger anions. Only mutations at S341 affected selectivity between monovalent and divalent anions. The data are consistent with a narrowing of the pore between the extracellular end and a constriction near the middle of the pore.

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No. Sentence Comment
62 S341E CFTR was a generous gift from D. Dawson (Oregon Health Sciences University, Portland, OR). Login to comment
94 All data are background subtracted, with the currents measured in the absence of Iso in the same oocyte as background, with the exception of experiments with S341E CFTR. Login to comment
97 However, currents in S341E CFTR-expressing oocytes were increased by ϳ30% on further stimulation with Iso and exhibited time-independent behavior in response to steps in membrane potential, indicating that these currents reflect activity of CFTR. Login to comment
98 S341E CFTR expressed well in oocytes so that the signal-to-noise ratio (compared to a background of an uninjected oocyte) was at least 40 for each experiment. Login to comment
99 Furthermore, the selectivity pattern described in Characterization of the WT CFTR pore: lyotropic selectivity and anion binding for S341E CFTR differed considerably from the recently described pattern for the endogenous Ca2ϩ -activated Cl- chan- nel of oocytes (34). Login to comment
100 Hence, we felt confident in ascribing anion currents in oocytes expressing this cRNA to the S341E CFTR mutant channels rather than to the endogenous Ca2ϩ -activated Cl-channel. Login to comment
143 Relative permeabilities for WT and mutant CFTRs for monovalent anions CFTR n NO3 Br SCN I ClO4 Acetate Isethionate Glutamate Gluconate WT 16 1.35Ϯ0.01 1.19Ϯ0.02 2.42Ϯ0.06 0.36Ϯ0.01 0.10Ϯ0.01 0.15Ϯ0.00* 0.24Ϯ0.01 0.24Ϯ0.01 0.18Ϯ0.01 K335A 5 1.35Ϯ0.01 1.36Ϯ0.03 3.10Ϯ0.11† 0.75Ϯ0.02† 0.12Ϯ0.01 0.06Ϯ0.01† 0.07Ϯ0.01† 0.07Ϯ0.01† 0.08Ϯ0.01† K335F 7 1.51Ϯ0.03† 1.36Ϯ0.02† 2.73Ϯ0.14 0.99Ϯ0.03† 0.20Ϯ0.02† 0.13Ϯ0.01 0.18Ϯ0.03 0.30Ϯ0.02 0.20Ϯ0.02 K335E 5 1.24Ϯ0.04 1.17Ϯ0.02 2.60Ϯ0.06 1.10Ϯ0.03† 0.23Ϯ0.01† 0.10Ϯ0.01† 0.11Ϯ0.01† 0.10Ϯ0.01† 0.11Ϯ0.01† T338A 5 1.74Ϯ0.07† 1.59Ϯ0.02† 4.35Ϯ0.24† 2.56Ϯ0.13† 1.84Ϯ0.08† 0.07Ϯ0.01† 0.06Ϯ0.01† 0.08Ϯ0.01† 0.08Ϯ0.01† T338E 3 3.65Ϯ0.19† 1.94Ϯ0.04† 4.29Ϯ0.13† 2.41Ϯ0.24† 1.18Ϯ0.06† 0.16Ϯ0.03 0.37Ϯ0.05† 0.36Ϯ0.01† 0.22Ϯ0.03 T339A 5 1.47Ϯ0.01 1.29Ϯ0.03 2.65Ϯ0.06 0.57Ϯ0.02† 0.24Ϯ0.04 0.10Ϯ0.02 0.19Ϯ0.02 0.18Ϯ0.01 0.15Ϯ0.01 S341A 6 1.91Ϯ0.02† 1.42Ϯ0.01† 3.10Ϯ0.09† 0.59Ϯ0.00*† 0.09Ϯ0.00* 0.11Ϯ0.01† 0.12Ϯ0.00*† 0.11Ϯ0.00*† 0.12Ϯ0.00*† S341E 12 2.01Ϯ0.10† 1.46Ϯ0.05† 2.81Ϯ0.18 0.84Ϯ0.00*† 0.31Ϯ0.03† 0.20Ϯ0.01 0.23Ϯ0.02 0.19Ϯ0.01 0.19Ϯ0.02 S341T 5 1.81Ϯ0.05† 1.39Ϯ0.03 3.15Ϯ0.15† 0.41Ϯ0.01 0.07Ϯ0.00* 0.05Ϯ0.00*† 0.06Ϯ0.00*† 0.03Ϯ0.01† 0.06Ϯ0.01† T1134A 6 1.43Ϯ0.02 1.30Ϯ0.02 2.66Ϯ0.02 0.46Ϯ0.00*† 0.06Ϯ0.00*† 0.08Ϯ0.01† 0.10Ϯ0.01† 0.11Ϯ0.01† 0.10Ϯ0.00*† T1134F 5 1.31Ϯ0.07 1.17Ϯ0.05 2.50Ϯ0.10 0.63Ϯ0.01† 0.08Ϯ0.00* 0.13Ϯ0.01 0.09Ϯ0.01† 0.18Ϯ0.02 0.13Ϯ0.01 T1134E 4 1.68Ϯ0.02† 1.39Ϯ0.05† 2.37Ϯ0.18 0.19Ϯ0.03† 0.20Ϯ0.03 0.06Ϯ0.01† 0.09Ϯ0.01† 0.08Ϯ0.01† 0.10Ϯ0.01† Values are means Ϯ SE with only data from the hyperpolarizing ramp protocol; n, no. of oocytes. Relative permeability, permeability of anion x to that of Cl. Anions are listed in order of increasing ionic radius. Login to comment
167 Selectivity sequences for WT and mutant CFTRs CFTR Selectivity Sequence by Relative Permeability WT SCNϾϾNO3 ϾBrϾClϾϾIϾisethionateϭglutamateϾgluconateϭacetateϾClO4 K335A SCNϾϾBrϭNO3 ϾClϾIϾϾClO4 Ͼgluconateϭisethionateϭglutamateϭacetate K335F SCNϾϾNO3 ϾBrϾClϭIϾϾglutamateϾgluconateϭClO4 ϭisethionateϾacetate K335E SCNϾϾNO3 ϾBrϭIϾClϾϾClO4 Ͼgluconateϭisethionateϭglutamateϭacetate T338A SCNϾϾIϾϾClO4 ϭNO3 ϾBrϾClϾϾgluconateϭisethionateϭglutamateϭacetate T338E SCNϾNO3 ϾIϾBrϾClO4 ϾClϾϾisethionateϭglutamateϾgluconateϭacetate T339A SCNϾϾNO3 ϾBrϾClϾϾIϾϾClO4 ϭisethionateϭglutamateϭgluconateϾacetate S341A SCNϾNO3 ϾBrϾClϾϾIϾϾgluconateϭisethionateϭglutamateϭacetateϭClO4 S341E SCNϾNO3 ϾBrϾClϾIϾϾClO4 Ͼisethionateϭacetateϭglutamateϭgluconate S341T SCNϾϾNO3 ϾBrϾClϾϾIϾϾClO4 ϭisethionateϭgluconateϭacetateϭglutamate T1134A SCNϾϾNO3 ϾBrϾClϾϾIϾϾglutamateϭisethionateϭgluconateϭacetateϭClO4 T1134F SCNϾϾNO3 ϾBrϾClϾϾIϾϾglutamateϾacetateϭgluconateϾisethionateϭClO4 T1134E SCNϾNO3 ϾBrϾClϾϾClO4 ϭIϾgluconateϭisethionateϭglutamateϭacetate L856 A REGION OF STRONG DISCRIMINATION IN THE CFTR PORE AJP-Lung Cell Mol Physiol • VOL 281 • OCTOBER 2001 • www.ajplung.org out propagation to distant sites. Login to comment
191 Relative conductances for WT and mutant CFTRs for monovalent anions CFTR n NO3 Br SCN I ClO4 Acetate Isethionate Glutamate Gluconate WT 16 0.87Ϯ0.01 0.77Ϯ0.01 0.18Ϯ0.01 0.25Ϯ0.01 0.23Ϯ0.01 0.55Ϯ0.01 0.50Ϯ0.01 0.57Ϯ0.02 0.56Ϯ0.02 K335A 5 0.88Ϯ0.04 0.77Ϯ0.02 0.30Ϯ0.02† 0.35Ϯ0.02 0.24Ϯ0.02 0.33Ϯ0.01† 0.32Ϯ0.02† 0.37Ϯ0.02† 0.38Ϯ0.02† K335F 7 1.21Ϯ0.05† 0.87Ϯ0.02† 0.55Ϯ0.02† 0.36Ϯ0.01† 0.19Ϯ0.01 0.34Ϯ0.01† 0.34Ϯ0.01† 0.41Ϯ0.01† 0.37Ϯ0.01† K335E 5 1.16Ϯ0.05† 0.91Ϯ0.02† 0.59Ϯ0.02† 0.51Ϯ0.02† 0.28Ϯ0.01 0.22Ϯ0.01† 0.25Ϯ0.01† 0.22Ϯ0.01† 0.24Ϯ0.01† T338A 5 1.20Ϯ0.13† 1.03Ϯ0.06† 0.98Ϯ0.12† 0.82Ϯ0.02† 0.50Ϯ0.04† 0.18Ϯ0.05† 0.08Ϯ0.01† 0.31Ϯ0.05† 0.29Ϯ0.05† T338E 3 3.66Ϯ0.36† 1.53Ϯ0.09† 1.80Ϯ0.12† 1.39Ϯ0.11† 0.87Ϯ0.03† 0.36Ϯ0.04† 0.56Ϯ0.17 0.44Ϯ0.03† 0.48Ϯ0.03† T339A 5 1.01Ϯ0.02† 0.77Ϯ0.03 0.22Ϯ0.01 0.31Ϯ0.03 0.23Ϯ0.01 0.38Ϯ0.02† 0.48Ϯ0.01 0.48Ϯ0.01 0.52Ϯ0.01 S341A 6 1.67Ϯ0.01† 1.08Ϯ0.01† 0.63Ϯ0.03† 0.26Ϯ0.00* 0.15Ϯ0.01† 0.63Ϯ0.01† 0.54Ϯ0.02 0.63Ϯ0.01 0.63Ϯ0.01 S341E 12 1.74Ϯ0.11† 1.14Ϯ0.02† 1.81Ϯ0.06† 0.48Ϯ0.01† 0.35Ϯ0.02† 0.28Ϯ0.01† 0.69Ϯ0.02† 0.65Ϯ0.01† 0.68Ϯ0.01† S341T 5 0.85Ϯ0.02 0.82Ϯ0.01 0.29Ϯ0.01† 0.22Ϯ0.01 0.13Ϯ0.01† 0.48Ϯ0.01 0.45Ϯ0.02 0.43Ϯ0.02 0.55Ϯ0.01 T1134A 6 0.83Ϯ0.02 0.78Ϯ0.01 0.24Ϯ0.01† 0.21Ϯ0.01 0.09Ϯ0.01† 0.39Ϯ0.01† 0.38Ϯ0.01† 0.39Ϯ0.01† 0.40Ϯ0.01 T1134F 5 0.68Ϯ0.03† 0.69Ϯ0.03† 0.36Ϯ0.01† 0.07Ϯ0.01† 0.16Ϯ0.01 0.48Ϯ0.02 0.30Ϯ0.02† 0.22Ϯ0.01† 0.32Ϯ0.02† T1134E 4 0.99Ϯ0.02† 1.00Ϯ0.02† 0.50Ϯ0.02† 0.20Ϯ0.03 0.26Ϯ0.02 0.32Ϯ0.03† 0.34Ϯ0.01† 0.34Ϯ0.03† 0.34Ϯ0.03† Values are means Ϯ SE with only data from the hyperpolarizing ramp protocol; n, no. of oocytes. Relative conductance, conductance of anion x to that of Cl. Anions are listed in order of increasing ionic radius. Login to comment
213 Vrev Cl in ND96 bath solution for WT and mutant CFTRs CFTR n Vrev Cl WT 16 -21.24Ϯ0.59 K335A 5 -22.12Ϯ0.35 K335F 7 -21.92Ϯ0.90 K335E 5 -22.88Ϯ0.36 T338A 5 -26.97Ϯ0.79* T338E 3 -20.58Ϯ1.07 T339A 5 -22.21Ϯ0.98 S341A 6 -21.21Ϯ0.56 S341E 12 -28.77Ϯ1.36* S341T 5 -26.62Ϯ1.43* T1134A 6 -28.33Ϯ1.23* T1134F 5 -19.74Ϯ0.73 T1134E 4 -27.54Ϯ1.27* Values are means Ϯ SE; n, no. of oocytes. Login to comment
276 S341E CFTR exhibited a larger shift in Vrev Cl and pronounced outward rectification, whereas T338E CFTR exhibited pronounced inward rectification. Login to comment
277 The opposite patterns of macroscopic rectification in T338E CFTR and S341E CFTR suggest that these two positions may lie on opposite sides of a barrier in the pore. Login to comment
287 In contrast, Gx/GCl values for all anions were altered in S341E CFTR (Table 4). Login to comment
289 Comparing S341E with S341A CFTR and T338E with T338A CFTR, we can see that the introduction of a negative charge at S341 more strongly destabilized the binding of SCN- (which is pronounced in WT CFTR) than did the equivalent mutation at T338. Login to comment
293 A prediction from the disruption of SCN- binding in S341E CFTR is that this mutation may result in disruption of DPC binding as well. Login to comment
294 To test this notion, we compared the blockade of CFTR macroscopic currents in oocytes expressing WT CFTR or S341E CFTR using methods established previously (50). Login to comment
296 In contrast, S341E CFTR was insensitive to DPC at all voltages, even at high concentration; in fact, 0.5 mM DPC led to a slight increase in current at all potentials. Login to comment
310 Currents carried by WT CFTR or S341E CFTR were measured in the absence of drug and in the presence of 100 (for WT CFTR) or 500 (for S341E CFTR) ␮M DPC applied to the bathing solution. Login to comment
313 S341E CFTR was not blocked by DPC, even at high concentrations. Login to comment
320 In fact, mutations T338E and S341E led to channels that could barely distinguish between monovalent anions. Login to comment
409 Mutation S341E had a greater effect on the ability of the channel to discriminate between monovalent anions than did any other glutamic acid substitution (Fig. 7). Login to comment
438 Also, it may be true that ions more closely approach a charge placed at S341 than a charge placed at T338 by virtue of the constriction, leading to greater destabilization of anion binding in S341E CFTR. Login to comment
439 Our results with K335E (outside the region of high discrimination) and S341E (inside the region of high discrimination) show that this interpretation is feasible. Login to comment
457 4) T338E CFTR exhibits pronounced inward rectification in the macroscopic I-V, whereas S341E CFTR exhibits pronounced outward rectification (Fig. 5). Login to comment

[hide] Voltage-sensitive gating induced by a mutation in ... Am J Physiol Lung Cell Mol Physiol. 2002 Jan;282(1):L135-45. Zhang ZR, Zeltwanger S, Smith SS, Dawson DC, McCarty NA
Voltage-sensitive gating induced by a mutation in the fifth transmembrane domain of CFTR.
Am J Physiol Lung Cell Mol Physiol. 2002 Jan;282(1):L135-45., [PMID:11741825]

Abstract [show]
A mutation in the fifth transmembrane domain of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel (V317E) resulted in whole cell currents that exhibited marked outward rectification on expression in Xenopus oocytes. However, the single-channel unitary current (i)-voltage (V) relationship failed to account for the rectification of whole cell currents. In excised patches containing one to a few channels, the time-averaged single-channel current (I)-V relationship (I = N x P(o) x i, where N is the number of active channels and P(o) is open probability) of V317E CFTR displayed outward rectification, whereas that of wild-type CFTR was linear, indicating that the P(o) of V317E CFTR is voltage dependent. The decrease in P(o) at negative potentials was due to both a decreased burst duration and a decreased opening rate that could not be ameliorated by a 10-fold increase in ATP concentration. This behavior appears to reflect a true voltage dependence of the gating process because the P(o)-V relationship did not depend on the direction of Cl(-) movement. The results are consistent with the introduction, by a point mutation, of a novel voltage-dependent gating mode that may provide a useful tool for probing the portions of the protein that move in response to ATP-dependent gating.

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No. Sentence Comment
314 Other glutamate substitutions in TM domains 1, 5, 6, and 12 have been investigated [G91E, G314E, and K335E (16); S341E and T1134E (20)], but none of these exhibited voltage-dependent gating (McCarty and Dawson, unpublished observations). Login to comment