ABCMdb

ABCC7 p.Lys1060Thr

Admin's notes:	Class III (gating defect) Veit et al.
ClinVar:	c.3179A>C , p.Lys1060Thr ? , not provided
CF databases:	c.3179A>C , p.Lys1060Thr (CFTR1) D , This mutation was detected by DGGE analysis and identified by direct sequencing. This mutation was found in one Spanish man with CBAVD.
Predicted by SNAP2:	A: N (53%), C: N (61%), D: D (71%), E: D (59%), F: D (66%), G: D (59%), H: N (66%), I: N (53%), L: D (53%), M: N (53%), N: D (53%), P: D (71%), Q: N (87%), R: N (87%), S: D (53%), T: N (57%), V: D (53%), W: D (71%), Y: D (53%),
Predicted by PROVEAN:	A: N, C: D, D: N, E: N, F: D, G: N, H: N, I: D, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: D, Y: N,

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III (gating defect) <a href="https://www.ncbi.nlm.nih.gov/pubmed/26823392">Veit et al.</a>
admin on 2016-08-19 15:16:22

Publications
[hide] Heterogeneity for mutations in the CFTR gene and c... Hum Reprod. 2000 Jul;15(7):1476-83. Casals T, Bassas L, Egozcue S, Ramos MD, Gimenez J, Segura A, Garcia F, Carrera M, Larriba S, Sarquella J, Estivill X
Heterogeneity for mutations in the CFTR gene and clinical correlations in patients with congenital absence of the vas deferens.
Hum Reprod. 2000 Jul;15(7):1476-83., [PMID:10875853]

Abstract [show]
Congenital absence of the vas deferens (CAVD) is a heterogeneous disorder, largely due to mutations in the cystic fibrosis (CFTR) gene. Patients with unilateral absence of the vas deferens (CUAVD) and patients with CAVD in association with renal agenesis appear to have a different aetiology to those with isolated CAVD. We have studied 134 Spanish CAVD patients [110 congenital bilateral absence of the vas deferens (CBAVD) and 24 CUAVD], 16 of whom (six CBAVD, 10 CUAVD) had additional renal anomalies. Forty-two different CFTR mutations were identified, seven of them being novel. Some 45% of the CFTR mutations were specific to CAVD, and were not found in patients with cystic fibrosis or in the general Spanish population. CFTR mutations were detected in 85% of CBAVD patients and in 38% of those with CUAVD. Among those patients with renal anomalies, 31% carried one CFTR mutation. Anomalies in seminal vesicles and ejaculatory ducts were common in patients with CAVD. The prevalence of cryptorchidism and inguinal hernia appeared to be increased in CAVD patients, as well as nasal pathology and frequent respiratory infections. This study confirms the molecular heterogeneity of CFTR mutations in CAVD, and emphasizes the importance of an extensive CFTR analysis in these patients. In contrast with previous studies, this report suggests that CFTR might have a role in urogenital anomalies.

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98 Vasograms performed in six patients with CUAVD E92K/- 5T/7T 1 not only confirmed ultrasonographic findings, but also showed 711ϩ1G→T/- 5T/7T 1 additional abnormalities at various levels of the seminal tract.R334W/- 5T/7T 1 S549R/- 5T/7T 1 The volume and consistency of testes was normal, except in 1949del84/- 5T/7T 1 patients with other concomitant pathologies, such as crypt- K1060T/- 5T/7T 1 orchidism (n ϭ 6), trauma (n ϭ 2), orchitis (n ϭ 2) orR1162X/- 5T/7T 1 S1235R/- 5T/7T 1 tumour (n ϭ 1). Login to comment

[hide] Misfolding of the cystic fibrosis transmembrane co... Biochemistry. 2008 Feb 12;47(6):1465-73. Epub 2008 Jan 15. Cheung JC, Deber CM
Misfolding of the cystic fibrosis transmembrane conductance regulator and disease.
Biochemistry. 2008 Feb 12;47(6):1465-73. Epub 2008 Jan 15., 2008-02-12 [PMID:18193900]

Abstract [show]
Understanding the structural basis for defects in protein function that underlie protein-based genetic diseases is the fundamental requirement for development of therapies. This situation is epitomized by the cystic fibrosis transmembrane conductance regulator (CFTR)-the gene product known to be defective in CF patients-that appears particularly susceptible to misfolding when its biogenesis is hampered by mutations at critical loci. While the primary CF-related defect in CFTR has been localized to deletion of nucleotide binding fold (NBD1) residue Phe508, an increasing number of mutations (now ca. 1,500) are being associated with CF disease of varying severity. Hundreds of these mutations occur in the CFTR transmembrane domain, the site of the protein's chloride channel. This report summarizes our current knowledge on how mutation-dependent misfolding of the CFTR protein is recognized on the cellular level; how specific types of mutations can contribute to the misfolding process; and describes experimental approaches to detecting and elucidating the structural consequences of CF-phenotypic mutations.

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90 In some additional examples, a number of mutations found in the fourth intracellular loop (H1054D, G1061R, L1065P, R1066C/H/L, Q1071P, L1077P, H1085R, W1098R, M1101K/ R) also affect the biosynthetic processing of CFTR (although function was not tested) (73); some intracellular loop 4 mutants (F1052V, K1060T, A1067T, G1069R, R1070Q/W) can process CFTR to the complex-glycosylated ("Band C") form but have altered channel activity compared to wild type. Login to comment

[hide] Effect of cystic fibrosis-associated mutations in ... J Biol Chem. 1996 Aug 30;271(35):21279-84. Cotten JF, Ostedgaard LS, Carson MR, Welsh MJ
Effect of cystic fibrosis-associated mutations in the fourth intracellular loop of cystic fibrosis transmembrane conductance regulator.
J Biol Chem. 1996 Aug 30;271(35):21279-84., [PMID:8702904]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) contains multiple membrane spanning sequences that form a Cl- channel pore and cytosolic domains that control the opening and closing of the channel. The fourth intracellular loop (ICL4), which connects the tenth and eleventh transmembrane spans, has a primary sequence that is highly conserved across species, is the site of a preserved sequence motif in the ABC transporter family, and contains a relatively large number of missense mutations associated with cystic fibrosis (CF). To investigate the role of ICL4 in CFTR function and to learn how CF mutations in this region disrupt function, we studied several CF-associated ICL4 mutants. We found that most ICL4 mutants disrupted the biosynthetic processing of CFTR, although not as severely as the most common DeltaF508 mutation. The mutations had no discernible effect on the channel's pore properties; but some altered gating behavior, the response to increasing concentrations of ATP, and stimulation in response to pyrophosphate. These effects on activity were similar to those observed with mutations in the nucleotide-binding domains, suggesting that ICL4 might help couple activity of the nucleotide-binding domains to gating of the Cl- channel pore. The data also explain how these mutations cause a loss of CFTR function and suggest that some patients with mutations in ICL4 may have a milder clinical phenotype because they retain partial activity of CFTR at the cell membrane.

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31 2 R1066S (C. Fe´rec, I. Quere, C. Verlingue, O. Raguenes, M.-P. Au- drezet, and B. Mercier, personal communication), F1074L (T. Casals, M. D. Ramos, J. Gime´nez, V. Nunes, and X. Estivill, personal communication), K1060T (T. Casals, M. Chillo´n, V. Nunes, J. Gime´nez, M. D. Ramos, and X. Estivill, personal communication), L1065R (T. Casals, M. D. Ramos, J. Gime´nez, V. Nunes, and X. Estivill, personal communication), T1086I (T. Bienvenu, S. Bousquet, C. Herbulot, C. Beldjord, and J. C. Kaplan, personal communication), and R1070W (M. Macek, S. Sedriks, S. Kiesewetter, and G. R. Cutting, personal communication). Login to comment

[hide] Disease-associated mutations in the fourth cytopla... J Biol Chem. 1996 Jun 21;271(25):15139-45. Seibert FS, Linsdell P, Loo TW, Hanrahan JW, Clarke DM, Riordan JR
Disease-associated mutations in the fourth cytoplasmic loop of cystic fibrosis transmembrane conductance regulator compromise biosynthetic processing and chloride channel activity.
J Biol Chem. 1996 Jun 21;271(25):15139-45., [PMID:8662892]

Abstract [show]
A cluster of 18 point mutations in exon 17b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has been detected in patients with cystic fibrosis. These mutations cause single amino acid substitutions in the most C-terminal cytoplasmic loop (CL4, residues 1035-1102) of the CFTR chloride channel. Heterologous expression of the mutants showed that 12 produced only core-glycosylated CFTR, which was retained in the endoplasmic reticulum; the other six mutants matured and reached the cell surface. In some cases substitution of one member of pairs of adjacent residues resulted in misprocessing, whereas the other did not. Thus, the secondary structure of CL4 may contribute crucially to the proper folding of the entire CFTR molecule. Cyclic AMP-stimulated iodide efflux was not detected from cells expressing the misprocessed variants but was from the other six, indicating that their mutations cause relatively subtle channel defects. Consistent with this, these latter mutations generally are present in patients who are pancreatic-sufficient, while the processing mutants are mostly from patients who are pancreatic-insufficient. Single-channel patch-clamp analysis demonstrated that the processed mutants had the same ohmic conductance as wild-type CFTR, but a lower open probability, generally due to an increase in channel mean closed time and a reduction in mean open time. This suggests that mutations in CL4 do not affect pore properties of CFTR, but disrupt the mechanism of channel gating.

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64 The mature forms of the other six mutants (F1052V, K1060T, A1067T, G1069R, R1070W, R1070Q) were produced in relatively normal amounts (band C), although for A1067T and R1070W CFTR the ratio of the complex-glycosylated to core-glycosylated bands was significantly lower than for wild-type CFTR. Login to comment
81 This showed that the level of activity for cells expressing each CFTR mutant did approximately correspond to the amount of mature protein in the sample, i.e. in COS-1 cells F1052V, K1060T, and G1069R produced efflux levels similar to wild-type CFTR in accordance with a level of protein expression similar to wild type. Login to comment
88 Other disease-causing CFTR mutants, which are appropriately processed and trafficked to the plasma membrane, show defective ion conduction properties (e.g. R334W, R347H, and R347P; Sheppard et al., 1993; Tabcharani et al., 1993) or defective regulation of channel activity (e.g. G551S, G1244E, S1255P, and G1349D; Anderson and Welsh, 1992). Login to comment
127 Symbols are as follows: A: छ, WT; E, F1052V; Ç, K1060T; µ, A1067T; Ⅺ, vector only control. Login to comment
142 A, examples of wild-type, F1052V, K1060T, A1067T, G1069R, R1070Q, and R1070W CFTR single channel currents recorded from inside-out membrane patches at a membrane potential of -30 mV. Login to comment
71 The mature forms of the other six mutants (F1052V, K1060T, A1067T, G1069R, R1070W, R1070Q) were produced in relatively normal amounts (band C), although for A1067T and R1070W CFTR the ratio of the complex-glycosylated to core-glycosylated bands was significantly lower than for wild-type CFTR. Login to comment
133 Symbols are as follows: A: L, WT; E, F1052V; &#c7;, K1060T; &#b5;, A1067T; M, vector only control. Login to comment
148 A, examples of wild-type, F1052V, K1060T, A1067T, G1069R, R1070Q, and R1070W CFTR single channel currents recorded from inside-out membrane patches at a membrane potential of 230 mV. Login to comment

[hide] Methods for screening in cystic fibrosis. Methods Mol Med. 1996;5:99-119. Schwarz M, Malone G
Methods for screening in cystic fibrosis.
Methods Mol Med. 1996;5:99-119., [PMID:21374513]

Abstract [show]
Cystic fibrosis (CF) is the most common lethal autosomal recessive disorder in Whites, with an incidence of approx 1 m 2500 live births and a carrier frequency of approx 1 in 25. Since the discovery of the cystic fibrosis transmembrane conductance regulator (CFTR) gene m 1989 (1-3), molecular genetics laboratories throughout the world have endeavored to identify the mutations present in their population of CF-bearing chromosomes. Since the entire CFTR gene and its intron-exon boundaries have been sequenced, mutation analysis in CF has become relatively simple, although time consuming. Generally, a number of different methods are applied to mutation analysis, but all involve an imtial step of amplification of part of the gene by polymerase chain reaction (PCR) (4), or a derivative of it, such as amplification refractory mutation system (ARMS) (5).

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82 For example the mutations AEl15 and K1060T, aswell asAF508, G542X, and RI 17H have been seenm CBAVD (29). Login to comment

[hide] Mutations in the cystic fibrosis gene in patients ... N Engl J Med. 1995 Jun 1;332(22):1475-80. Chillon M, Casals T, Mercier B, Bassas L, Lissens W, Silber S, Romey MC, Ruiz-Romero J, Verlingue C, Claustres M, et al.
Mutations in the cystic fibrosis gene in patients with congenital absence of the vas deferens.
N Engl J Med. 1995 Jun 1;332(22):1475-80., [PMID:7739684]

Abstract [show]
BACKGROUND: Congenital bilateral absence of the vas deferens (CBAVD) is a form of male infertility in which mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene have been identified. The molecular basis of CBAVD is not completely understood. Although patients with cystic fibrosis have mutations in both copies of the CFTR gene, most patients with CBAVD have mutations in only one copy of the gene. METHODS: To investigate CBAVD at the molecular level, we have characterized the mutations in the CFTR gene in 102 patients with this condition. None had clinical manifestations of cystic fibrosis. We also analyzed a DNA variant (the 5T allele) in a noncoding region of CFTR that causes reduced levels of the normal CFTR protein. Parents of patients with cystic fibrosis, patients with types of infertility other than CBAVD, and normal subjects were studied as controls. RESULTS: Nineteen of the 102 patients with CBAVD had mutations in both copies of the CFTR gene, and none of them had the 5T allele. Fifty-four patients had a mutation in one copy of CFTR, and 34 of them (63 percent) had the 5T allele in the other CFTR gene. In 29 patients no CFTR mutations were found, but 7 of them (24 percent) had the 5T allele. In contrast, the frequency of this allele in the general population was about 5 percent. CONCLUSIONS: Most patients with CBAVD have mutations in the CFTR gene. The combination of the 5T allele in one copy of the CFTR gene with a cystic fibrosis mutation in the other copy is the most common cause of CBAVD: The 5T allele mutation has a wide range of clinical presentations, occurring in patients with CBAVD or moderate forms of cystic fibrosis and in fertile men.

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74 OF PATIENTS POLYT GENOTYPE† ⌬F508/R668C ⌬F508/D1152H ⌬F508/D1270N ⌬F508/R75L ⌬F508/R117H ⌬F508/L206W ⌬F508/R258G ⌬F508/S1235R ⌬F508/R347H ⌬F508/R347H R117H/G1349D R117H/712-1G→T G149R/R668C R347H/R1066H R553X/R668C R1070W/2869insG ⌬F508/- G542X/- W1282X/- R334W/- K1060T/- R1162X/- N1303K/- A800G/- ⌬F508/- ⌬F508/- ⌬F508/- ⌬E115/- R117H/- R347H/- G542X/- R553X/- 1677delTA/- 2184delA/- 2789ϩ5G→Α/- S1235R/- W1282X/- -/- -/- -/- -/- 2 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 22 4 3 1 1 1 1 1 7 1 1 1 1 2 1 1 1 1 1 1 1 3 3 1 19 9T/7T 9T/7T 9T/7T 9T/7T 9T/7T 9T/9T 9T/7T 9T/7T 9T/7T 9T/9T 7T/7T 7T/9T 9T/7T 9T/7T 7T/7T 7T/7T 9T/5T 9T/5T 7T/5T 7T/5T 7T/5T 7T/5T 9T/5T 5T/5T 9T/7T 9T/9T 7T/7T 7T/7T 7T/7T 9T/7T 9T/7T 7T/7T 7T/7T 7T/7T 7T/7T 7T/9T 7T/7T 9T/5T 7T/5T 5T/5T 7T/7T -/- 3 7T/9T *Data were obtained from the Spanish population analyzed in this study. Login to comment

[hide] Extensive analysis of 40 infertile patients with c... Hum Genet. 1995 Feb;95(2):205-11. Casals T, Bassas L, Ruiz-Romero J, Chillon M, Gimenez J, Ramos MD, Tapia G, Narvaez H, Nunes V, Estivill X
Extensive analysis of 40 infertile patients with congenital absence of the vas deferens: in 50% of cases only one CFTR allele could be detected.
Hum Genet. 1995 Feb;95(2):205-11., [PMID:7532150]

Abstract [show]
Mutations in the cystic fibrosis (CF) conductance transmembrane regulator (CFTR) gene have been detected in patients with CF and in males with infertility attributable to congenital bilateral absence of the vas deferens (CBAVD). Thirty individuals with CBAVD and 10 with congenital unilateral absence of the vas deferens (CUAVD) were analyzed by single-strand conformation analysis and denaturing gradient gel electrophoresis for mutations in most of the CFTR gene. All 40 individuals were pancreatic sufficient, but twenty patients had recurrent or sporadic respiratory infections, asthma/asthmatic bronchitis, and/or rhino-sinusitis. Agenesia or displasia of one or both seminal vesicles was detected in 30 men and other urogenital malformations were present in six subjects. Among the 40 samples, we identified 13 different CFTR mutations, two of which were previously unknown. One new mutation in exon 4 was the deletion of glutamic acid at codon 115 (delta E115). A second new mutation was found in exon 17b, viz., an A --> C substitution at position 3311, changing lysine to threonine at codon 1060 (K1060T). CFTR mutations were detected in 22 out of 30 (73.3%) CBAVD patients and in one out of 10 (10%) CUAVD individuals, showing a significantly lower incidence of CFTR mutations in CBAVD/CUAVD patients (P << 0.0001), compared with that found in the CF patient population. Only three CBAVD patients were found with more than one CFTR mutation (delta F508/L206W, delta F508/R74W + D1270N, R117H/712-1G --> T), highlighting L206W, R74W/D1270N, and R117H as benign CF mutations. Sweat electrolyte values were increased in 76.6% of CBAVD patients, but three individuals without CFTR mutations had normal sweat electrolyte levels (10% of the total CBAVD patients), suggesting that factors other than CFTR mutations are involved in CBAVD. The failure to identify a second mutation in exons and their flanking regions of the CFTR gene suggests that these mutations could be located in introns or in the promoter region of CFTR. Such mutations could result in CFTR levels below the minimum 6%-10% necessary for normal protein function.

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7 A second new mutation was found in exon 17b, viz., an A--~C substitution at position 3311, changing lysine to threonine at codon 1060 (K1060T). Login to comment
76 For the observed changes, we considered the strong association between mutations and CFTR microsatellite haplo- K1060T AaCTsor,~AcA~_ QA.,~ATaG .c ' {i a ;, ' ! Login to comment
86 One abnormal pattern in exon 17b was caused by an A--~C substitution at position 3311, changing lysine to threonine at codon 1060 (K1060T); this is a new missense mutation in the CFTR gene (Fig. 3). Login to comment
103 In 13 cases, the mutations are known to be associated with severe CF (AF508, G542X, Rl162X and 1677delTA), whereas in five cases, the phenotypic effect of the mutation is still unknown (AEll5, K1060T, R334W, R1070W, and 2789 + 5G---)A); in one case (Rll7H), the mutation is known to result in mild CE Of these mutations, R334W seems to cause pancreatic insufficiency with a variable age of onset (X. Estivill, in press), whereas mutation 2789 + 5G--)A (W. E. Jr. High- smith, personal communication to the CFGAC) has frequently been found in adult CF patients and is probably involved in a mild phenotype (T. Casals et al. unpublished). Login to comment
116 The two new mutations detected here (AEll5 and K1060T) are located in transmembranic domains of CFTR, where it is well known that changes affect ion-channel transport (Cheng et al. 1990). Login to comment
119 For mutation K1060T, the lysine residue is conserved in the mouse, bovine, and Xenopus (Tucker et al. 1992), suggesting that this position in the second transmembrane domain might be more crucial. Login to comment
121 Although there is no doubt about the involvement of AE115 and K1060T in CBAVD, the genuine clinical significance of these two new mutations cannot be established, since only one mutation was detected in each individual. Login to comment
122 Further examples of mutations AE115 and K1060T should provide appropriate phenotype/genotype correlations. Login to comment

[hide] Effect of ivacaftor on CFTR forms with missense mu... J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23. Van Goor F, Yu H, Burton B, Hoffman BJ
Effect of ivacaftor on CFTR forms with missense mutations associated with defects in protein processing or function.
J Cyst Fibros. 2014 Jan;13(1):29-36. doi: 10.1016/j.jcf.2013.06.008. Epub 2013 Jul 23., [PMID:23891399]

Abstract [show]
BACKGROUND: Ivacaftor (KALYDECO, VX-770) is a CFTR potentiator that increased CFTR channel activity and improved lung function in patients age 6 years and older with CF who have the G551D-CFTR gating mutation. The aim of this in vitro study was to evaluate the effect of ivacaftor on mutant CFTR protein forms with defects in protein processing and/or channel function. METHODS: The effect of ivacaftor on CFTR function was tested in electrophysiological studies using a panel of Fischer rat thyroid (FRT) cells expressing 54 missense CFTR mutations that cause defects in the amount or function of CFTR at the cell surface. RESULTS: Ivacaftor potentiated multiple mutant CFTR protein forms that produce functional CFTR at the cell surface. These included mutant CFTR forms with mild defects in CFTR processing or mild defects in CFTR channel conductance. CONCLUSIONS: These in vitro data indicated that ivacaftor is a broad acting CFTR potentiator and could be used to help stratify patients with CF who have different CFTR genotypes for studies investigating the potential clinical benefit of ivacaftor.

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44 None M1V A46D E56K P67L R74W G85E E92K D110E D110H R117C R117H E193K L206W R334W I336K T338I S341P R347H R347P R352Q A455E L467P S492F F508del V520F A559T R560S R560T A561E Y569D D579G R668C L927P S945L S977F L997F F1052V H1054D K1060T L1065P R1066C R1066H R1066M A1067T R1070Q R1070W F1074L L1077P H1085R M1101K D1152H S1235R D1270N N1303K 0 100 200 300 400 500 600 * * * CFTR Mutation mRNA (% Normal CFTR) Fig. 1. Login to comment
64 Mutant CFTR form CFTR processing Mature/total % Normal CFTR Normal 0.89 &#b1; 0.01 100.0 &#b1; 18.5 G85E -0.05 &#b1; 0.04 -1.0 &#b1; 0.9 R560S 0.00 &#b1; 0.00 0.0 &#b1; 0.0 R1066C 0.02 &#b1; 0.01 0.0 &#b1; 0.0 S492F 0.00 &#b1; 0.00 0.1 &#b1; 0.1 R560T 0.01 &#b1; 0.01 0.2 &#b1; 0.1 V520F 0.05 &#b1; 0.03 0.3 &#b1; 0.2 M1101K 0.05 &#b1; 0.03 0.3 &#b1; 0.1 A561E 0.08 &#b1; 0.04 0.5 &#b1; 0.2 R1066M 0.02 &#b1; 0.02 0.5 &#b1; 0.4 N1303K 0.02 &#b1; 0.02 0.5 &#b1; 0.3 A559T 0.16 &#b1; 0.09 0.6 &#b1; 0.2 M1V 0.06 &#b1; 0.06 0.7 &#b1; 0.6 Y569D 0.11 &#b1; 0.04 0.6 &#b1; 0.2 R1066H 0.08 &#b1; 0.02a 0.7 &#b1; 0.2a L1065P 0.05 &#b1; 0.05 1.0 &#b1; 0.8 L467P 0.10 &#b1; 0.07 1.2 &#b1; 0.8 L1077P 0.08 &#b1; 0.04 1.5 &#b1; 0.6 A46D 0.21 &#b1; 0.08 1.9 &#b1; 0.5a E92K 0.06 &#b1; 0.05 1.9 &#b1; 1.3 H1054D 0.09 &#b1; 0.04 1.9 &#b1; 0.8 F508del 0.09 &#b1; 0.02a 2.3 &#b1; 0.5a H1085R 0.06 &#b1; 0.01a 3.0 &#b1; 0.7a I336K 0.42 &#b1; 0.05a 6.5 &#b1; 0.7a L206W 0.35 &#b1; 0.10a 6.8 &#b1; 1.7a F1074L 0.52 &#b1; 0.03a 10.9 &#b1; 0.6a A455E 0.26 &#b1; 0.10a 11.5 &#b1; 2.5a E56K 0.29 &#b1; 0.04a 12.2 &#b1; 1.5a R347P 0.48 &#b1; 0.04a 14.6 &#b1; 1.8a R1070W 0.61 &#b1; 0.04a 16.3 &#b1; 0.6a P67L 0.36 &#b1; 0.04a 28.4 &#b1; 6.8a R1070Q 0.90 &#b1; 0.01a 29.5 &#b1; 1.4a S977F 0.97 &#b1; 0.01a 37.3 &#b1; 2.4a A1067T 0.78 &#b1; 0.03a 38.6 &#b1; 6.1a D579G 0.72 &#b1; 0.02a 39.3 &#b1; 3.1a D1270N 1.00 &#b1; 0.00a,c 40.7 &#b1; 1.2a S945L 0.65 &#b1; 0.04a 42.4 &#b1; 8.9a L927P 0.89 &#b1; 0.01a,b 43.5 &#b1; 2.5a,b R117C 0.87 &#b1; 0.02a,b 49.1 &#b1; 2.9a,b T338I 0.93 &#b1; 0.03a,b 54.2 &#b1; 3.7a,b L997F 0.90 &#b1; 0.04a,b 59.8 &#b1; 10.4a,b D110H 0.97 &#b1; 0.01a,b 60.6 &#b1; 1.5a,b S341P 0.79 &#b1; 0.02a 65.0 &#b1; 4.9a,b R668C 0.94 &#b1; 0.03a,b 68.5 &#b1; 1.9a,b R74W 0.78 &#b1; 0.01a 69.0 &#b1; 2.7a,b D110E 0.92 &#b1; 0.05a,b 87.5 &#b1; 9.5a,b R334W 0.91 &#b1; 0.05a,b 97.6 &#b1; 10.0a,b K1060T 0.87 &#b1; 0.02a,b 109.9 &#b1; 28.0a,b R347H 0.96 &#b1; 0.02a,c 120.7 &#b1; 2.8a,b S1235R 0.96 &#b1; 0.00a,c 139.0 &#b1; 9.0a,b E193K 0.84 &#b1; 0.02a,b 143.0 &#b1; 17.1a,b R117H 0.86 &#b1; 0.01a,b 164.5 &#b1; 34.2a,b R352Q 0.98 &#b1; 0.01a,b 179.9 &#b1; 8.0a,c F1052V 0.90 &#b1; 0.01a,b 189.9 &#b1; 33.1a,b D1152H 0.96 &#b1; 0.02a,c 312.0 &#b1; 45.5a,b Notes to Table 1: Quantification of steady-state CFTR maturation expressed as the mean (&#b1;SEM; n = 5-9) ratio of mature CFTR to total CFTR (immature plus mature) or level of mature mutant CFTR relative to mature normal-CFTR (% normal CFTR) in FRT cells individually expressing CFTR mutations. Login to comment
74 Because the level of CFTR mRNA was similar across the panel of cell lines tested, the range in baseline activity and ivacaftor response likely reflects the severity of the functional defect and/or the 0 50 100 150 200 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L E56K P67L R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V Baseline With ivacaftor * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Chloride transport (% Normal) Mutant CFTR form 0 100 200 300 400 S341P R347P L467P S492F A559T A561E Y569D L1065P R1066C R1066M L1077P M1101K N1303K R560S L927P R560T H1085R V520F E92K M1V F508del H1054D I336K A46D G85E R334W T338I R1066H R352Q R117C L206W R347H S977F S945L A455E F1074L P67L E56K R1070W D110H D579G D110E R1070Q L997F A1067T E193K R117H R74W K1060T R668C D1270N D1152H S1235R F1052V * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Mature CFTR (% Normal) Mutant CFTR form A B Fig. 2. Login to comment
82 Mutation Patientsa Chloride transport (bc;A/cm2 ) Chloride transport (% normal) EC50 Baseline With ivacaftor Baseline With ivacaftor Fold increase over baselineb Normal 204.5 &#b1; 33.3 301.3 &#b1; 33.8c 100.0 &#b1; 16.3 147.3 &#b1; 16.5c 1.5 266 &#b1; 42 G551D 1282 1.5 &#b1; 0.7 113.2 &#b1; 13.0c 1.0 &#b1; 0.5 55.3 &#b1; 6.3c 55.3 312 &#b1; 73 F1052V 12 177.3 &#b1; 13.7 410.2 &#b1; 11.3c 86.7 &#b1; 6.7 200.7 &#b1; 5.6c 2.3 177 &#b1; 14 S1235R ND 160.6 &#b1; 25.7 352.1 &#b1; 43.4c 78.5 &#b1; 12.6 172.2 &#b1; 21.2c 2.2 282 &#b1; 104 D1152H 185 117.3 &#b1; 23.0 282.7 &#b1; 46.9c 57.4 &#b1; 11.2 138.2 &#b1; 22.9c 2.4 178 &#b1; 67 D1270N 32 109.5 &#b1; 20.5 209.5 &#b1; 27.4c 53.6 &#b1; 10.0 102.4 &#b1; 13.4c 1.9 254 &#b1; 56 R668C 45 99.0 &#b1; 9.4 217.6 &#b1; 11.7c 48.4 &#b1; 4.6 106.4 &#b1; 5.7c 2.2 517 &#b1; 105 K1060T ND 89.0 &#b1; 9.8 236.4 &#b1; 20.3c 43.5 &#b1; 4.8 115.6 &#b1; 9.9c 2.7 131 &#b1; 73 R74W 25 86.8 &#b1; 26.9 199.1 &#b1; 16.8c 42.5 &#b1; 13.2 97.3 &#b1; 8.2c 2.3 162 &#b1; 17 R117H 739 67.2 &#b1; 13.3 274.1 &#b1; 32.2c 32.9 &#b1; 6.5 134.0 &#b1; 15.7c 4.1 151 &#b1; 14 E193K ND 62.2 &#b1; 9.8 379.1 &#b1; 1.1c 30.4 &#b1; 4.8 185.4 &#b1; 1.0c 6.1 240 &#b1; 20 A1067T ND 55.9 &#b1; 3.2 164.0 &#b1; 9.7c 27.3 &#b1; 1.6 80.2 &#b1; 4.7c 2.9 317 &#b1; 214 L997F 27 43.7 &#b1; 3.2 145.5 &#b1; 4.0c 21.4 &#b1; 1.6 71.2 &#b1; 2.0c 3.3 162 &#b1; 12 R1070Q 15 42.0 &#b1; 0.8 67.3 &#b1; 2.9c 20.6 &#b1; 0.4 32.9 &#b1; 1.4c 1.6 164 &#b1; 20 D110E ND 23.3 &#b1; 4.7 96.4 &#b1; 15.6c 11.4 &#b1; 2.3 47.1 &#b1; 7.6c 4.1 213 &#b1; 51 D579G 21 21.5 &#b1; 4.1 192.0 &#b1; 18.5c 10.5 &#b1; 2.0 93.9 &#b1; 9.0c 8.9 239 &#b1; 48 D110H 30 18.5 &#b1; 2.2 116.7 &#b1; 11.3c 9.1 &#b1; 1.1 57.1 &#b1; 5.5c 6.2 249 &#b1; 59 R1070W 13 16.6 &#b1; 2.6 102.1 &#b1; 3.1c 8.1 &#b1; 1.3 49.9 &#b1; 1.5c 6.2 158 &#b1; 48 P67L 53 16.0 &#b1; 6.7 88.7 &#b1; 15.7c 7.8 &#b1; 3.3 43.4 &#b1; 7.7c 5.6 195 &#b1; 40 E56K ND 15.8 &#b1; 3.1 63.6 &#b1; 4.4c 7.7 &#b1; 1.5 31.1 &#b1; 2.2c 4.0 123 &#b1; 33 F1074L ND 14.0 &#b1; 3.4 43.5 &#b1; 5.4c 6.9 &#b1; 1.6 21.3 &#b1; 2.6c 3.1 141 &#b1; 19 A455E 120 12.9 &#b1; 2.6 36.4 &#b1; 2.5c 6.3 &#b1; 1.2 17.8 &#b1; 1.2c 2.8 170 &#b1; 44 S945L 63 12.3 &#b1; 3.9 154.9 &#b1; 47.6c 6.0 &#b1; 1.9 75.8 &#b1; 23.3c 12.6 181 &#b1; 36 S977F 9 11.3 &#b1; 6.2 42.5 &#b1; 19.1c 5.5 &#b1; 3.0 20.8 &#b1; 9.3c 3.8 283 &#b1; 36 R347H 65 10.9 &#b1; 3.3 106.3 &#b1; 7.6c 5.3 &#b1; 1.6 52.0 &#b1; 3.7c 9.8 280 &#b1; 35 L206W 81 10.3 &#b1; 1.7 36.4 &#b1; 2.8c 5.0 &#b1; 0.8 17.8 &#b1; 1.4c 3.6 101 &#b1; 13 R117C 61 5.8 &#b1; 1.5 33.7 &#b1; 7.8c 2.9 &#b1; 0.7 16.5 &#b1; 3.8c 5.7 380 &#b1; 136 R352Q 46 5.5 &#b1; 1.0 84.5 &#b1; 7.8c 2.7 &#b1; 0.5 41.3 &#b1; 3.8c 15.2 287 &#b1; 75 R1066H 29 3.0 &#b1; 0.3 8.0 &#b1; 0.8c 1.5 &#b1; 0.1 3.9 &#b1; 0.4c 2.6 390 &#b1; 179 T338I 54 2.9 &#b1; 0.8 16.1 &#b1; 2.4c 1.4 &#b1; 0.4 7.9 &#b1; 1.2c 5.6 334 &#b1; 38 R334W 150 2.6 &#b1; 0.5 10.0 &#b1; 1.4c 1.3 &#b1; 0.2 4.9 &#b1; 0.7c 3.8 259 &#b1; 103 G85E 262 1.6 &#b1; 1.0 1.5 &#b1; 1.2 0.8 &#b1; 0.5 0.7 &#b1; 0.6 NS NS A46D ND 2.0 &#b1; 0.6 1.1 &#b1; 1.1 1.0 &#b1; 0.3 0.5 &#b1; 0.6 NS NS I336K 29 1.8 &#b1; 0.2 7.4 &#b1; 0.1c 0.9 &#b1; 0.1 3.6 &#b1; 0.1c 4 735 &#b1; 204 H1054D ND 1.7 &#b1; 0.3 8.7 &#b1; 0.3c 0.8 &#b1; 0.1 4.2 &#b1; 0.1c 5.3 187 &#b1; 20 F508del 29,018 0.8 &#b1; 0.6 12.1 &#b1; 1.7c 0.4 &#b1; 0.3 5.9 &#b1; 0.8c 14.8 129 &#b1; 38 M1V 9 0.7 &#b1; 1.4 6.5 &#b1; 1.9c 0.4 &#b1; 0.7 3.2 &#b1; 0.9c 8.0 183 &#b1; 85 E92K 14 0.6 &#b1; 0.2 4.3 &#b1; 0.8c 0.3 &#b1; 0.1 2.1 &#b1; 0.4c 7.0 198 &#b1; 46 V520F 58 0.4 &#b1; 0.2 0.5 &#b1; 0.2 0.2 &#b1; 0.1 0.2 &#b1; 0.1 NS NS H1085R ND 0.3 &#b1; 0.2 2.1 &#b1; 0.4 0.2 &#b1; 0.1 1.0 &#b1; 0.2 NS NS R560T 180 0.3 &#b1; 0.3 0.5 &#b1; 0.5 0.1 &#b1; 0.1 0.2 &#b1; 0.2 NS NS L927P 15 0.2 &#b1; 0.1 10.7 &#b1; 1.7c 0.1 &#b1; 0.1 5.2 &#b1; 0.8c 52.0 313 &#b1; 66 R560S ND 0.0 &#b1; 0.1 -0.2 &#b1; 0.2 0.0 &#b1; 0.0 -0.1 &#b1; 0.1 NS NS N1303K 1161 0.0 &#b1; 0.0 1.7 &#b1; 0.3 0.0 &#b1; 0.0 0.8 &#b1; 0.2 NS NS M1101K 79 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1077P 42 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066M ND 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R1066C 100 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS L1065P 25 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS Y569D 9 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS A561E ND 0.0 &#b1; 0.1 0.0 &#b1; 0.1 0.0 &#b1; 0.0 0.0 &#b1; 0.1 NS NS A559T 43 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S492F 16 0.0 &#b1; 0.0 1.7 &#b1; 1.2 0.0 &#b1; 0.0 0.8 &#b1; 0.6 NS NS L467P 16 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS R347P 214 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 0.0 &#b1; 0.0 NS NS S341P 9 0.0 &#b1; 0.0 0.2 &#b1; 0.2 0.0 &#b1; 0.0 0.1 &#b1; 0.1 NS NS a Number of individuals with the individual mutation in the CFTR-2 database (www.CFTR2.org). Login to comment
92 Mutant CFTR forms that did not significantly respond to ivacaftor under the experimental conditions used in this study were generally associated with severe defects in CFTR processing A B C D E F 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 S1235R D1152H F1052V D1270N ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R668C K1060T R74W R117H ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 E193K A1067T L997F R1070Q ivacaftor [Log M] Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) Chloride Transport ( &#b5;A/cm 2 ) 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 D110E D579G D110H R1070W ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F1074L E56K P67L A455E ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 R347H S945L L206W S977F ivacaftor [Log M] 0 100 200 300 400 -8 -6 -4 0 T338I R1066H R117C R352Q ivacaftor [Log M] 0 100 200 300 400 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K ivacaftor [Log M] 0 5 10 15 20 -9 -8 -7 -6 -5 -4 0 F508del R334W H1054D E92K R1066H T338I ivacaftor [Log M] G H I Fig. 3. Login to comment

[hide] An electrostatic interaction at the tetrahelix bun... J Biol Chem. 2014 Oct 31;289(44):30364-78. doi: 10.1074/jbc.M114.595710. Epub 2014 Sep 4. Wang W, Roessler BC, Kirk KL
An electrostatic interaction at the tetrahelix bundle promotes phosphorylation-dependent cystic fibrosis transmembrane conductance regulator (CFTR) channel opening.
J Biol Chem. 2014 Oct 31;289(44):30364-78. doi: 10.1074/jbc.M114.595710. Epub 2014 Sep 4., [PMID:25190805]

Abstract [show]
The CFTR channel is an essential mediator of electrolyte transport across epithelial tissues. CFTR opening is promoted by ATP binding and dimerization of its two nucleotide binding domains (NBDs). Phosphorylation of its R domain (e.g. by PKA) is also required for channel activity. The CFTR structure is unsolved but homology models of the CFTR closed and open states have been produced based on the crystal structures of evolutionarily related ABC transporters. These models predict the formation of a tetrahelix bundle of intracellular loops (ICLs) during channel opening. Here we provide evidence that residues E267 in ICL2 and K1060 in ICL4 electrostatically interact at the interface of this predicted bundle to promote CFTR opening. Mutations or a thiol modifier that introduced like charges at these two positions substantially inhibited ATP-dependent channel opening. ATP-dependent activity was rescued by introducing a second site gain of function (GOF) mutation that was previously shown to promote ATP-dependent and ATP-independent opening (K978C). Conversely, the ATP-independent activity of the K978C GOF mutant was inhibited by charge- reversal mutations at positions 267 or 1060 either in the presence or absence of NBD2. The latter result indicates that this electrostatic interaction also promotes unliganded channel opening in the absence of ATP binding and NBD dimerization. Charge-reversal mutations at either position markedly reduced the PKA sensitivity of channel activation implying strong allosteric coupling between bundle formation and R domain phosphorylation. These findings support important roles of the tetrahelix bundle and the E267-K1060 electrostatic interaction in phosphorylation-dependent CFTR gating.

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238 Seibert et al. (43) provided the first evidence that the K1060 position is relevant to CFTR gating in their single channel analysis of a mutation (K1060T) that reportedly associates with mild disease (i.e. CBAVD). Login to comment
254 This moderate degree of inhibition by the uncharged K1060T substitution is consistent with our findings. Login to comment

[hide] Murine and human CFTR exhibit different sensitivit... Am J Physiol Lung Cell Mol Physiol. 2015 Oct 1;309(7):L687-99. doi: 10.1152/ajplung.00181.2015. Epub 2015 Jul 24. Cui G, McCarty NA
Murine and human CFTR exhibit different sensitivities to CFTR potentiators.
Am J Physiol Lung Cell Mol Physiol. 2015 Oct 1;309(7):L687-99. doi: 10.1152/ajplung.00181.2015. Epub 2015 Jul 24., [PMID:26209275]

Abstract [show]
Development of therapeutic molecules with clinical efficacy as modulators of defective CFTR includes efforts to identify potentiators that can overcome or repair the gating defect in mutant CFTR channels. This has taken a great leap forward with the identification of the potentiator VX-770, now available to patients as "Kalydeco." Other small molecules with different chemical structure also are capable of potentiating the activity of either wild-type or mutant CFTR, suggesting that there are features of the protein that may be targeted to achieve stimulation of channel activity by structurally diverse compounds. However, neither the mechanisms by which these compounds potentiate mutant CFTR nor the site(s) where these compounds bind have been identified. This knowledge gap partly reflects the lack of appropriate experimental models to provide clues toward the identification of binding sites. Here, we have compared the channel behavior and response to novel and known potentiators of human CFTR (hCFTR) and murine (mCFTR) expressed in Xenopus oocytes. Both hCFTR and mCFTR were blocked by GlyH-101 from the extracellular side, but mCFTR activity was increased with GlyH-101 applied directly to the cytoplasmic side. Similarly, glibenclamide only exhibited a blocking effect on hCFTR but both blocked and potentiated mCFTR in excised membrane patches and in intact oocytes. The clinically used CFTR potentiator VX-770 transiently increased hCFTR by approximately 13% but potentiated mCFTR significantly more strongly. Our results suggest that mCFTR pharmacological sensitivities differ from hCFTR, which will provide a useful tool for identifying the binding sites and mechanism for these potentiators.

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306 However, recent data indicating that VX-770 potentiates channels bearing multiple disease-causing mutations, spread across CFTR, and that VX-770 potentiates one mutant but not another one in the same domain (for example, VX-770 potentiated TM mutants T338I- and R347H- but not S341P- and E92K-CFTR and potentiated cytoplasmic loop mutants E193K- and K1060T- but not R1066M- and L1065P-CFTR) do not support this conclusion (30, 38). Login to comment