ABCMdb

ABCC7 p.Glu822Lys

ClinVar:	c.2464G>A , p.Glu822Lys ? , not provided c.2464G>T , p.Glu822* D , Pathogenic
CF databases:	c.2464G>T , p.Glu822* D , CF-causing c.2464G>A , p.Glu822Lys (CFTR1) ? , A nucleotide change, G->A was observed in exon 13 at position 2596 leading to E822K. The patient is 13 years old, and pancreatic insufficient. The other mutation is still unknown. This mutation was found once among 28 Belgian CF chromosomes.
Predicted by SNAP2:	A: D (53%), C: D (66%), D: D (66%), F: D (75%), G: D (71%), H: D (71%), I: D (63%), K: N (61%), L: D (66%), M: D (71%), N: D (71%), P: D (80%), Q: D (59%), R: D (75%), S: D (66%), T: D (63%), V: D (59%), W: D (80%), Y: D (75%),
Predicted by PROVEAN:	A: N, C: D, D: N, F: D, G: N, H: N, I: D, K: N, L: D, M: D, N: N, P: N, Q: N, R: N, S: N, T: N, V: D, W: D, Y: D,

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Publications
[hide] Insight in eukaryotic ABC transporter function by ... FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19. Frelet A, Klein M
Insight in eukaryotic ABC transporter function by mutation analysis.
FEBS Lett. 2006 Feb 13;580(4):1064-84. Epub 2006 Jan 19., 2006-02-13 [PMID:16442101]

Abstract [show]
With regard to structure-function relations of ATP-binding cassette (ABC) transporters several intriguing questions are in the spotlight of active research: Why do functional ABC transporters possess two ATP binding and hydrolysis domains together with two ABC signatures and to what extent are the individual nucleotide-binding domains independent or interacting? Where is the substrate-binding site and how is ATP hydrolysis functionally coupled to the transport process itself? Although much progress has been made in the elucidation of the three-dimensional structures of ABC transporters in the last years by several crystallographic studies including novel models for the nucleotide hydrolysis and translocation catalysis, site-directed mutagenesis as well as the identification of natural mutations is still a major tool to evaluate effects of individual amino acids on the overall function of ABC transporters. Apart from alterations in characteristic sequence such as Walker A, Walker B and the ABC signature other parts of ABC proteins were subject to detailed mutagenesis studies including the substrate-binding site or the regulatory domain of CFTR. In this review, we will give a detailed overview of the mutation analysis reported for selected ABC transporters of the ABCB and ABCC subfamilies, namely HsCFTR/ABCC7, HsSUR/ABCC8,9, HsMRP1/ABCC1, HsMRP2/ABCC2, ScYCF1 and P-glycoprotein (Pgp)/MDR1/ABCB1 and their effects on the function of each protein.

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No. Sentence Comment
345 E822K and E826K reduced channel conductance and opening [160,165]. Login to comment

[hide] A functional R domain from cystic fibrosis transme... Proc Natl Acad Sci U S A. 2000 May 9;97(10):5657-62. Ostedgaard LS, Baldursson O, Vermeer DW, Welsh MJ, Robertson AD
A functional R domain from cystic fibrosis transmembrane conductance regulator is predominantly unstructured in solution.
Proc Natl Acad Sci U S A. 2000 May 9;97(10):5657-62., 2000-05-09 [PMID:10792060]

Abstract [show]
Phosphorylation of the regulatory (R) domain initiates cystic fibrosis transmembrane conductance regulator (CFTR) Cl(-) channel activity. To discover how the function of this domain is determined by its structure, we produced an R domain protein (R8) that spanned residues 708-831 of CFTR. Phosphorylated, but not unphosphorylated, R8 stimulated activity of CFTR channels lacking this domain, indicating that R8 is functional. Unexpectedly, this functional R8 was predominantly random coil, as revealed by CD and limited proteolysis. The CD spectra of both phosphorylated and nonphosphorylated R8 were similar in aqueous buffer. The folding agent trimethylamine N-oxide induced only a small increase in the helical content of nonphosphorylated R8 and even less change in the helical content of phosphorylated R8. These data, indicating that the R domain is predominantly random coil, may explain the seemingly complex way in which phosphorylation regulates CFTR channel activity.

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198 From this region, the mutations R792G, A800G, E822K, and E826K increase or decrease current, but have not been reported to alter channel properties (38, 39). Login to comment

[hide] A short segment of the R domain of cystic fibrosis... J Biol Chem. 2002 Jun 21;277(25):23019-27. Epub 2002 Apr 11. Xie J, Adams LM, Zhao J, Gerken TA, Davis PB, Ma J
A short segment of the R domain of cystic fibrosis transmembrane conductance regulator contains channel stimulatory and inhibitory activities that are separable by sequence modification.
J Biol Chem. 2002 Jun 21;277(25):23019-27. Epub 2002 Apr 11., 2002-06-21 [PMID:11950844]

Abstract [show]
The regulatory (R) domain of the cystic fibrosis transmembrane conductance regulator (CFTR) contains consensus phosphorylation sites for cAMP-dependent protein kinase (PKA) that are the basis for physiological regulation of the CFTR chloride channel. A short peptide segment in the R domain with a net negative charge of B9 (amino acids 817-838, NEG2) and predicted helical tendency is shown to play a critical role in CFTR chloride channel function. Deletion of NEG2 from CFTR completely eliminates the PKA dependence of channel activity. Exogenous NEG2 peptide interacts with CFTR to exert both stimulatory and inhibitory effects on the channel function. The NEG2 peptide with sequence scrambled to remove helical tendencies also inhibits channel function, but does not stimulate. Similar results are found for a NEG2 peptide whose helical structure is disrupted by a proline residue. When six of the negatively charged carboxylic acid residues are replaced by their cognate amides, reducing net negative charge to B3, but increasing helical propensity as assessed by circular dichroism, the peptide stimulates CFTR channel function, but does not inhibit. We speculate that the NEG2 region interacts with other cytosolic domains of CFTR to control opening and closing transitions of the chloride channel.

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No. Sentence Comment
232 Three mutations are reported in the NEG2 region (E822K, E826K, and D836Y), two of which were obtained from patients with cystic fibrosis (E822K and D836Y). Login to comment
233 Single channel studies of E822K and E826K indicate that both mutations result in reduced Po compared with wt-CFTR (34). Login to comment

[hide] Cystic fibrosis: a worldwide analysis of CFTR muta... Hum Mutat. 2002 Jun;19(6):575-606. Bobadilla JL, Macek M Jr, Fine JP, Farrell PM
Cystic fibrosis: a worldwide analysis of CFTR mutations--correlation with incidence data and application to screening.
Hum Mutat. 2002 Jun;19(6):575-606., [PMID:12007216]

Abstract [show]
Although there have been numerous reports from around the world of mutations in the gene of chromosome 7 known as CFTR (cystic fibrosis transmembrane conductance regulator), little attention has been given to integrating these mutant alleles into a global understanding of the population molecular genetics associated with cystic fibrosis (CF). We determined the distribution of CFTR mutations in as many regions throughout the world as possible in an effort designed to: 1) increase our understanding of ancestry-genotype relationships, 2) compare mutational arrays with disease incidence, and 3) gain insight for decisions regarding screening program enhancement through CFTR multi-mutational analyses. Information on all mutations that have been published since the identification and cloning of the CFTR gene's most common allele, DeltaF508 (or F508del), was reviewed and integrated into a centralized database. The data were then sorted and regional CFTR arrays were determined using mutations that appeared in a given region with a frequency of 0.5% or greater. Final analyses were based on 72,431 CF chromosomes, using data compiled from over 100 original papers, and over 80 regions from around the world, including all nations where CF has been studied using analytical molecular genetics. Initial results confirmed wide mutational heterogeneity throughout the world; however, characterization of the most common mutations across most populations was possible. We also examined CF incidence, DeltaF508 frequency, and regional mutational heterogeneity in a subset of populations. Data for these analyses were filtered for reliability and methodological strength before being incorporated into the final analysis. Statistical assessment of these variables revealed that there is a significant positive correlation between DeltaF508 frequency and the CF incidence levels of regional populations. Regional analyses were also performed to search for trends in the distribution of CFTR mutations across migrant and related populations; this led to clarification of ancestry-genotype patterns that can be used to design CFTR multi-mutation panels for CF screening programs. From comprehensive assessment of these data, we offer recommendations that multiple CFTR alleles should eventually be included to increase the sensitivity of newborn screening programs employing two-tier testing with trypsinogen and DNA analysis.

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109 Mutational Arrays, Detection Rates and Methods by Region* Estimated Projected detection of Number of Number of Country/ allele two CFTR mutations chromosomes Region Mutation array detectiona mutationsb includedc (max/min)d Reference Europe Albania ∆F508 (72.4%) C276X (0.7%) 74.5 55.5 4 270/146 CFGAC [1994]; Macek et al. G85E (0.7%) R1070Q (0.7%) [2002] Austria ∆F508 (62.9%) 457TAT→G (1.2%) 76.6 58.7 11 1516/580 Estiville et al. [1997]; Dörk et al. (total) G542X (3.3%) 2183AA→G (0.7%) [2000]; Macek et al. [2002] CFTRdele2,3 (2.1%) N1303K (0.6%) R1162X (1.9%) I148T (0.5%) R553X (1.7%) R117H (0.5%) G551D (1.2%) Austria ∆F508 (74.6%) 2183AA→G (2.4%) 95.3 90.8 8 126 Stuhrmann et al. [1997] (tyrol) R1162X (8.7%) G551D (1.6%) G542X (2.4%) R347P (1.6%) 2789+5G→A (2.4%) Q39X (1.6%) Belarus ∆F508 (61.2%) R553X (0.5%) 75.2 56.6 9 278/188 Dörk et al. [2000]; Macek et al. G542X (4.5%) R334W (0.5%) [2002] CFTRdele2,3 (3.3%) R347P (0.5%) N1303K (3.2%) S549N (0.5%) W1282X (1.0%) Belgium ∆F508 (75.1%) 622-1A→C (0.5%) 100.0 100.0 27 1504/522 Cuppens et al. [1993]; Mercier et G542X (3.5%) G458V (0.5%) al. [1993]; CFGAC [1994]; N1303K (2.7%) 1898+G→C (0.5%) Estivill et al.[1997] R553X (1.7%) G970R (0.5%) 1717-1G→A (1.6%) 4218insT (0.5%) E60X (1.6%) 394delTT (0.5%) W1282X (1.4%) K830X (0.5%) 2183A→G+2184delA (1.2%) E822K (0.5%) W401X (1.0%) 3272-1G→A (0.5%) A455E (1.0%) S1161R (0.5%) 3272-26A→G (1.0%) R1162X (0.5%) S1251N (1.0%) 3750delAG (0.5%) S1235R (0.8%) S1255P (0.5%) ∆I507 (0.6%) Bulgaria ∆F508 (63.6%) R75Q (1.0%) 93.0 86.5 21 948/432 Angelicheva et al. [1997]; (total) N1303K (5.6%) 2183AA→G (0.9%) Estivill et al. [1997]; Macek G542X (3.9%) G1244V+S912L (0.9%) et al. [2002] R347P (2.2%) G85E (0.9%) 1677delTA (2.1%) 2184insA (0.9%) R1070Q (1.8%) L88X+G1069R (0.8%) Q220X (1.2%) 2789+5G→A (0.8%) 3849+10KbC→T (1.1%) G1244E (0.8%) W1282X (1.0%) 1717-1G→A (0.8%) 2176insC (1.0%) Y919C (0.7%) G1069R (1.0%) WORLDWIDEANALYSISOFCFTRMUTATIONS581 Bulgaria 1) DF508 4) 1677delTA - - 6 13 Angelicheva et al. [1997] (ethnic 2) R347P 5) Q493R Turks) 3) G542X 6) L571S - - 1 30 Angelicheva et al. [1997] Bulgaria 1) DF508 (100.0%) (Gypsy) Croatia ∆F508 (64.5%) G551D (1.1%) 72.5 52.6 5 276 Macek et al. [2002] G542X (3.3%) 3849+10KbC→T (0.7%) N1303K (2.9%) Czech ∆F508 (70.0%) 1898+1G→T (2.0%) 89.6 80.3 10 2196/628 CFGAC [1994]; Estiville et al. Republic CFTRdele2,3 (5.5%) 2143delT (1.2%) [1997]; Dörk et al. [2000]; G551D (3.8%) R347P (0.8%) Macek et al. [2002] N1303K (2.9%) 3849+10KbC→T (0.6%) G542X (2.2%) W1282X (0.6%) Denmark ∆F508 (87.5%) G542X (0.7%) 92.3 85.2 6 1888/678 CFGAC [1994]; Schwartz et al. (excluding 394delTT (1.8%) 621+1G→T (0.6%) [1994]; Estiville et al. [1997] Faroe) N1303K (1.1%) 3659delC (0.6%) Estonia ∆F508 (51.7%) R117C (1.7%) 80.2 64.3 10 165/80 Estivill et al. [1997]; Klaassen et 394delTT (13.3%) E217G (1.7%) al. [1998]; Macek et al. S1235R (3.3%) R1066H (1.7%) [2002] 359insT (1.7%) 3659delC (1.7%) I1005R (1.7%) S1169X (1.7%) Finland ∆F508 (46.2%) G542X (1.9%) 78.8 62.1 4 132/52 CFGAC [1994]; Kere et al. 394delTT (28.8%) 3372delA (1.9%) [1994]; Estivill et al. [1997] France ∆F508 (67.7%) 2789+5G→T (0.79%) 79.7 63.6 12 17854/7420 Chevalier-Porst et al. [1994]; (total) G542X (2.94%) 2184delA+2183A→G (0.77%) Estivill et al. [1997]; Claustres et al. [2000]; Guilloud-Bataille N1303K (1.83%) G551D (0.74%) et al. [2000] 1717-1G→A (1.35%) 1078delT (0.63%) W1282X (0.91%) ∆I507 (0.62%) R553X (0.86%) Y122K (0.59%) France ∆F508 (75.8%) R297Q (0.8%) 98.7 97.4 18 599/365 Férec et al. [1992]; Scotet et al. (Brittany) 1078delT (4.0%) R347H (0.8%) [2000] G551D (3.6%) I1234V (0.8%) N1303K (3.0%) R553X (0.8%) R117H (1.7%) 2789+5G→A (0.8%) 3272-26A→G (1.3%) 4005+1G→A (0.7%) G542X (1.1%) 621+1G→T (0.6%) 1717-1G→A (1.0%) ∆I507 (0.6%) G1249R (0.8%) W846X (0.5%) France ∆F508 (70.0%) N1303K (0.8%) 90.4 81.7 16 250 Claustres et al. [1993] (southern) G542X (6.4%) 3737delA (0.8%) 1717-1G→A (1.6%) R1162X (0.8%) L206W (1.2%) Y1092X (0.8%) R334W (1.2%) S945L (0.8%) ∆I507 (1.2%) K710X (0.8%) 2184delA (1.2%) 1078delT (0.8%) R1158X (1.2%) Y122X (0.8%) (Continued) BOBADILLAETAL. Login to comment

[hide] The phenotypic consequences of CFTR mutations. Ann Hum Genet. 2003 Sep;67(Pt 5):471-85. Rowntree RK, Harris A
The phenotypic consequences of CFTR mutations.
Ann Hum Genet. 2003 Sep;67(Pt 5):471-85., [PMID:12940920]

Abstract [show]
Cystic fibrosis is a common autosomal recessive disorder that primarily affects the epithelial cells in the intestine, respiratory system, pancreas, gall bladder and sweat glands. Over one thousand mutations have currently been identified in the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene that are associated with CF disease. There have been many studies on the correlation of the CFTR genotype and CF disease phenotype; however, this relationship is still not well understood. A connection between CFTR genotype and disease manifested in the pancreas has been well described, but pulmonary disease appears to be highly variable even between individuals with the same genotype. This review describes the current classification of CFTR mutation classes and resulting CF disease phenotypes. Complex disease alleles and modifier genes are discussed along with alternative disorders, such as disseminated bronchiectasis and pancreatitis, which are also thought to result from CFTR mutations.

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No. Sentence Comment
78 Three mutant CFTR proteins, G622D, R792G and E822K, that were transiently expressed in COS cells showed lower chloride channel activities when compared to wild-type CFTR, whereas mutants H620Q and A800G showed increased activities. Login to comment

[hide] Mutations that permit residual CFTR function delay... Respir Res. 2010 Oct 8;11:140. Green DM, McDougal KE, Blackman SM, Sosnay PR, Henderson LB, Naughton KM, Collaco JM, Cutting GR
Mutations that permit residual CFTR function delay acquisition of multiple respiratory pathogens in CF patients.
Respir Res. 2010 Oct 8;11:140., [PMID:20932301]

Abstract [show]
BACKGROUND: Lung infection by various organisms is a characteristic feature of cystic fibrosis (CF). CFTR genotype effects acquisition of Pseudomonas aeruginosa (Pa), however the effect on acquisition of other infectious organisms that frequently precede Pa is relatively unknown. Understanding the role of CFTR in the acquisition of organisms first detected in patients may help guide symptomatic and molecular-based treatment for CF. METHODS: Lung infection, defined as a single positive respiratory tract culture, was assessed for 13 organisms in 1,381 individuals with CF. Subjects were divided by predicted CFTR function: 'Residual': carrying at least one partial function CFTR mutation (class IV or V) and 'Minimal' those who do not carry a partial function mutation. Kaplan-Meier estimates were created to assess CFTR effect on age of acquisition for each organism. Cox proportional hazard models were performed to control for possible cofactors. A separate Cox regression was used to determine whether defining infection with Pa, mucoid Pa or Aspergillus (Asp) using alternative criteria affected the results. The influence of severity of lung disease at the time of acquisition was evaluated using stratified Cox regression methods by lung disease categories. RESULTS: Subjects with 'Minimal' CFTR function had a higher hazard than patients with 'Residual' function for acquisition of 9 of 13 organisms studied (HR ranging from 1.7 to 3.78 based on the organism studied). Subjects with minimal CFTR function acquired infection at a younger age than those with residual function for 12 of 13 organisms (p-values ranging: < 0.001 to 0.017). Minimal CFTR function also associated with younger age of infection when 3 alternative definitions of infection with Pa, mucoid Pa or Asp were employed. Risk of infection is correlated with CFTR function for 8 of 9 organisms in patients with good lung function (>90%ile) but only 1 of 9 organisms in those with poorer lung function (<50%ile). CONCLUSIONS: Residual CFTR function correlates with later onset of respiratory tract infection by a wide spectrum of organisms frequently cultured from CF patients. The protective effect conferred by residual CFTR function is diminished in CF patients with more advanced lung disease.

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74 For Pa, the hazard ratio Table 1 Classification of CFTR alleles Category Mutation Specific mutations Class I Defective Protein Synthesis (nonsense, frameshift, aberrant splicing) 1078delT, 1154 insTC, 1525-2A > G, 1717-1G > A, 1898+1G > A, 2184delA, 2184 insA, 3007delG, 3120+1G > A, 3659delC, 3876delA, 3905insT, 394delTT, 4010del4, 4016insT, 4326delTC, 4374+1G > T, 441delA, 556delA, 621+1G > T, 621-1G > T, 711+1G > T, 875+1G > C, E1104X, E585X, E60X, E822X, G542X, G551D/R553X, Q493X, Q552X, Q814X, R1066C, R1162X, R553X, V520F, W1282X, Y1092X Class II Abnormal Processing and Trafficking A559T, D979A, ΔF508, ΔI507, G480C, G85E, N1303K, S549I, S549N, S549R Class III Defective Channel Regulation/Gating G1244E, G1349D, G551D, G551S, G85E, H199R, I1072T, I48T, L1077P, R560T, S1255P, S549 (R75Q) Class IV Decreased Channel Conductance A800G, D1152H, D1154G, D614G, delM1140, E822K, G314E, G576A, G622D, G85E, H620Q, I1139V, I1234V, L1335P, M1137V, P67L, R117C, R117P, R117H, R334W, R347H, R347P, R347P/ R347H, R792G, S1251N, V232D Class V Reduced Synthesis and/or Trafficking 2789+5G > A, 3120G > A, 3272-26A > G, 3849+10kbC > T, 5T variant, 621+3A > G, 711+3A > G, A445E, A455E, IVS8 poly T, P574H was increased 3 fold for those with 'Minimal` function when compared to those with 'Residual` function. Login to comment

[hide] Characterization of 19 disease-associated missense... Hum Mol Genet. 1998 Oct;7(11):1761-9. Vankeerberghen A, Wei L, Jaspers M, Cassiman JJ, Nilius B, Cuppens H
Characterization of 19 disease-associated missense mutations in the regulatory domain of the cystic fibrosis transmembrane conductance regulator.
Hum Mol Genet. 1998 Oct;7(11):1761-9., [PMID:9736778]

Abstract [show]
In order to gain a better insight into the structure and function of the regulatory domain (RD) of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, 19 RD missense mutations that had been identified in patients were functionally characterized. Nine of these (I601F, L610S, A613T, D614G, I618T, L619S, H620P, G628R and L633P) resulted in aberrant processing. No or a very small number of functional CFTR proteins will therefore appear at the cell membrane in cells expressing these mutants. These mutations were clustered in the N-terminal part of the RD, suggesting that this subdomain has a folding pattern that is very sensitive to amino acid changes. Mutations that caused no aberrant processing were further characterized at the electrophysiological level. First, they were studied at the whole cell level in Xenopus laevis oocytes. Mutants that induced a whole cell current that was significantly different from wild-type CFTR were subsequently analysed at the single channel level in COS1 cells transiently expressing the different mutant and wild-type proteins. Three mutant chloride channels, G622D, R792G and E822K CFTR, were characterized by significantly lower intrinsic chloride channel activities compared with wild-type CFTR. Two mutations, H620Q and A800G, resulted in increased intrinsic chloride transport activities. Finally, T665S and E826K CFTR had single channel properties not significantly different from wild-type CFTR.

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7 Three mutant chloride channels, G622D, R792G and E822K CFTR, were characterized by significantly lower intrinsic chloride channel activities compared with wild-type CFTR. Login to comment
68 Primers used for mutagenesis Primer Sequence I601F (a1933t) 5'-CTA ACA AAA CTA GGT TTT TGG TCA CTT C-3' L610S (t1961c) 5'-CTA AAA TGG AAC ATT CAA AGA AAG CTG-3' A613T (g1969a) 5'-CAT TTA AAG AAA ACT GAC AAA ATA TTA-3' D614G (a1973g) 5'-CAT TTA AAG AAA GCT GGC AAA ATA TTA A-3' I618T (t1985c) 5'-GAC AAA ATA TTA ACT TTG CAT GAA GG-3' L619S (t1988c) 5'-GAC AAA ATA TTA ATT TCG CAT GAA GGT-3' H620P (a1991c) 5'-CAA AAT ATT AAT TTT GCC TGA AGG TAG C-3' H620Q (t1992g) 5'-AAT ATT AAT TTT GCA GGA AGG TAG CAG-3' G622D (g1997a) 5'-TTG CAT GAA GAT AGC AGC TAT TTT TAT G-3' G628R (g2014c) 5'-GCA GCT ATT TTT ATC GGA CAT TTT C-3' L633P (t2030c) 5'-CAT TTT CAG AAC CCC AAA ATC TAC AGC-3' D648V (a2075t) 5'-CTC ATG GGA TGT GTT TCT TTC GAC C-3' T665S (a2125t) 5'-CAA TCC TAA CTG AGT CCT TAC ACC G-3' F693L (t2209c) 5'-CAG ACT GGA GAG CTT GGG GAA AAA AG-3' R766M (g2429t) 5'-GCA CGA AGG ATG CAG TCT GTC CTG-3' R792G (c2506g) 5'-CAG CAT CCA CAG GAA AAG TGT CAC TG-3' A800G (c2531g) 5'-CTG GCC CCT CAG GGA AAC TTG ACT G-3' I807M (a2553g) 5'-CTG AAC TGG ATA TGT ATT CAA GAA GG-3' E822K (g2596a) 5'-GGC TTG GAA ATA AGT AAA GAA ATT AAC G-3' E826K (g2608a) 5'-GAA GAA ATT AAC AAA GAA GAC TTA AAG-3' Selection primer BstBI 5'-CTC TGG GGT CCG GAA TGA CCG AC-3' Two primers were used for each mutagenesis reaction. Login to comment
77 Mutations detected in patients (I601F, L610S, A613T, D614G, I618T, L619S, H620P, H620Q, D622G, G628R, L633P, T665S, F693L, K698R, V754M, R766M, R792G, A800G, I807M, E822K and E826K) are indicated in bold and underlined, the PKA phosphorylation sites by an arrow and the two acidic domains are boxed. Login to comment
83 Four mutations (T665S, R792G, E822K and E826K) caused a significant reduction in the cAMP-induced chloride current. Login to comment
87 Maturation pattern of RD mutations and their associated phenotype found in patients with the indicated genotype (when the mutation is associated with CF, only the pancreas status is given) Mutation A-form B-form C-form Clinical data Genotype Phenotype Reference I601F + + - I601F/G542X PS M. Schwarz, personal communication L610S + + - Unknown Unknown A613T + + - Unknown Unknown D614G + + - D614G/unknown PI 14 I618T + + - I618T/dF508 PS G.R. Cutting, personal communication L619S + + - L619S/unknown PI B. Tümmler, personal communication H620P + + - H620P/R1158X PS M. Schwarz, personal communication H620Q + + + H620Q/dF508 PI T. Dörk, personal communication G622D + + + G622D/unknown Oligospermia J. Zielenski, personal communication G628R + + - Unknown Unknown L633P + + - L633P/3659delC M. Schwarz, personal communication D648V + + + D648V/3849+10kb C/T PI C. Ferec, personal communication T665S + + + Unknown Unknown F693L + + + F693L/W1282X Healthy C. Ferec; CF Genetic Analysis Consortium R766M + + + R766M/R792G CBAVD D. Glavac, personal communication R792G + + + R766M/R792G CBAVD D. Glavac, personal communication A800G + + + A800G/unknown CBAVD 34 I807M + + + I807M/unknown CBAVD Our observation E822K + + + E822K/unknown PI 35 E826K + + + E826K/unknown Thoracic sarcoidosis C. Bombieri, personal communication +, the protein matures up to that form; -, the protein does not reach the respective maturation step. Login to comment
97 G622D, R792G and E822K gave rise to a CFTR chloride channel with a significantly lower Po than wild-type CFTR; H620Q and A800G CFTR resulted in channels with significantly higher Po. Login to comment
123 Mutations that did not affect maturation (H620Q, G622D, D648V, T665S, F693L, R766M, R792G, A800G, I807M, E822K and E826K) were subsequently analysedat theelectrophysiologi- cal level. Login to comment
124 Three of these (G622D, R792G and E822K) gave rise to chloride channels with significantly lower Po than the wild-type channel. Login to comment

[hide] Biochemical implications of sequence comparisons o... Arch Biochem Biophys. 2002 May 15;401(2):215-22. Tan AL, Ong SA, Venkatesh B
Biochemical implications of sequence comparisons of the cystic fibrosis transmembrane conductance regulator.
Arch Biochem Biophys. 2002 May 15;401(2):215-22., [PMID:12054472]

Abstract [show]
The cystic fibrosis transmembrane conductance regulator (CFTR) is a chloride channel that is both of medical significance in humans and of interest with regard to osmoregulation in aquatic organisms. CFTR is composed of five domains: two membrane-spanning domains, two nucleotide-binding domains, and a regulatory domain. Notwithstanding the plethora of information concerning the structure and function of CFTR, the biochemistry of many facets of CFTR are not completely understood. In this regard, we have performed a sequence alignment of representative vertebrate CFTR with the aim of generating hypotheses on the functional significance of conserved and variable residues. Postulates on function common to all organisms are: (i) Thr338 in the sixth transmembrane segment could have a function related to that of the pore-lining residue Lys335, and it is possible that Thr338 hydrogen bonds to Lys335, thus indirectly affecting anion permeability; (ii) the fragment (111)PDNKE could be an ion sensor; (iii) motifs in the two nucleotide-binding domains reflect differential ATP binding and hydrolysis; and (iv) an interaction in the R domain involving (765)RRQSVL and the C terminal end of the domain results in an inhibitory conformation. Major adaptations in fishes include variations in the postulated ion sensor (111)PDNKE, and the absence of a proline residue in the R domain with consequent higher chloride efflux.

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156 In contrast, the mutation E822K resulted in a diminution of channel activity [43]. Login to comment

[hide] Phosphorylation site independent single R-domain m... FEBS Lett. 1998 Nov 13;439(1-2):121-6. Wei L, Vankeerberghen A, Cuppens H, Droogmans G, Cassiman JJ, Nilius B
Phosphorylation site independent single R-domain mutations affect CFTR channel activity.
FEBS Lett. 1998 Nov 13;439(1-2):121-6., [PMID:9849891]

Abstract [show]
We investigated CFTR channel activity of mature R-domain mutants showing single alterations at sites other than the predicted phosphorylation sites. All mutations were found in cystic fibrosis (CF) patients (H620Q, E822K and E826K). The macroscopic CFTR chloride conductance induced by phosphorylation was significantly enhanced in Xenopus oocytes injected with mRNA of H620Q but reduced in the E822K and E826K mutants compared to wild type CFTR. The anion permeability sequence for all three mutants was the same as that of wild type CFTR. Cell attached single channel studies in COS cells revealed that both open channel probability and/or the number of functional channels were either higher (H620Q) or lower (E822K and E826K) than in wild type CFTR. Single channel conductances were unchanged in all mutants. Our results suggest that additional sites in the R-domain other than phosphorylation sites influence gating of CFTR channels.

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No. Sentence Comment
1 All mutations were found in cystic fibrosis (CF) patients (H620Q, E822K and E826K). Login to comment
2 The macroscopic CFTR chloride conductance induced by phosphorylation was significantly enhanced in Xenopus oocytes injected with mRNA of H620Q but reduced in the E822K and E826K mutants compared to wild type CFTR. Login to comment
4 Cell attached single channel studies in COS cells revealed that both open channel probability and/or the number of functional channels were either higher (H620Q) or lower (E822K and E826K) than in wild type CFTR. Login to comment
25 Three di¡erent mutations, t1992g (= H620Q), g2596a (= E822K) and g2608a (= E826K), were introduced using the Transformer Site-Directed Mutagenesis kit (Clontech). Login to comment
76 COS cells were transfected with wt CFTR, E822K CFTR (top), H620Q CFTR (bottom) and E826K CFTR (bottom) and selected for 2 weeks with G418. Login to comment
88 In this study, the maturation pattern of three mutant R-domain proteins (H620Q-CFTR, E822K-CFTR and E826K-CFTR) has been characterized. Login to comment
92 Whole cells currents of mutants in Xenopus oocytes Whole cell membrane currents were recorded from Xenopus oocytes injected with RNA transcribed from either wild type or mutant (H620Q, E822K, E826K) constructs. Login to comment
100 The two R-domain proteins E822K and E826K, in which a negatively charged glutamic acid was exchanged for a positively charged lysine, showed a signi'cantly smaller phos-cock activated conductance. Login to comment
101 Oocytes expressing the mutant R-domain protein (H620Q), in which a predominantly positively charged histidine was substituted by a less charged glutamine (at pH 7.2), showed a much larger conductance activated by application of phos-cock. Login to comment
103 The conductance for E822K and E826K was 3.55 þ 0.44 WS (n = 6) and 4.24 þ 0.37 WS (n = 6), as compared to 7.57 þ 0.65 WS (n = 14) in the wild type. Login to comment
134 We found that the open probability of the E822K and E826K mutants was signi'cantly lower than that of wild type CFTR, whereas that of the H620Q mutant was strongly enhanced compared to wild type (not shown). Login to comment
136 The average number of activated channels is 2.6 þ 0.306 (n = 10) for wild-type CFTR, 3.51 þ 0.428 (n = 6) for H620Q, 1.0 þ 0.000 (n = 4) for E822K and 1.66 þ 0.211 (n = 6) for E826K. Login to comment
137 The di¡erences between wild type CFTR and E822K and E826K are signi'- cant (P 6 0.05). Login to comment
141 All the mutations studied here are located outside the phosphorylation sites, which may suggest that other regions in the R-domain, especially the highly conserved regions where E822K and E826K were l,ocated are important for the regulation of the CFTR Cl3 channel. Login to comment
145 A comparison of the three R-domain mutants leads to a remarkable conclusion: both mutations, E822K and E826K, in which negatively charged glutamic acids were replaced by positively charged lysine had a signi'cantly reduced CFTR channel activity, whereas the H620Q mutation, in which positively charged histidine was replaced by the more neutral amino acid glutamine, had a much higher channel activity. Login to comment
155 However, it may be not enough for interpreting a mutant like E822K, in which only one positively charge mutation in the R-domain almost completely eliminates single channel activity. Login to comment
74 COS cells were transfected with wt CFTR, E822K CFTR (top), H620Q CFTR (bottom) and E826K CFTR (bottom) and selected for 2 weeks with G418. Login to comment
86 In this study, the maturation pattern of three mutant R-domain proteins (H620Q-CFTR, E822K-CFTR and E826K-CFTR) has been characterized. Login to comment
90 Whole cells currents of mutants in Xenopus oocytes Whole cell membrane currents were recorded from Xenopus oocytes injected with RNA transcribed from either wild type or mutant (H620Q, E822K, E826K) constructs. Login to comment
98 The two R-domain proteins E822K and E826K, in which a negatively charged glutamic acid was exchanged for a positively charged lysine, showed a signi'cantly smaller phos-cock activated conductance. Login to comment
132 We found that the open probability of the E822K and E826K mutants was signi'cantly lower than that of wild type CFTR, whereas that of the H620Q mutant was strongly enhanced compared to wild type (not shown). Login to comment
135 The di&#a1;erences between wild type CFTR and E822K and E826K are signi'- cant (P 6 0.05). Login to comment
139 All the mutations studied here are located outside the phosphorylation sites, which may suggest that other regions in the R-domain, especially the highly conserved regions where E822K and E826K were l,ocated are important for the regulation of the CFTR Cl3 channel. Login to comment
143 A comparison of the three R-domain mutants leads to a remarkable conclusion: both mutations, E822K and E826K, in which negatively charged glutamic acids were replaced by positively charged lysine had a signi'cantly reduced CFTR channel activity, whereas the H620Q mutation, in which positively charged histidine was replaced by the more neutral amino acid glutamine, had a much higher channel activity. Login to comment
153 However, it may be not enough for interpreting a mutant like E822K, in which only one positively charge mutation in the R-domain almost completely eliminates single channel activity. Login to comment

[hide] Definition of a "functional R domain" of the cysti... Mol Genet Metab. 2000 Sep-Oct;71(1-2):245-9. Chen JM, Scotet V, Ferec C
Definition of a "functional R domain" of the cystic fibrosis transmembrane conductance regulator.
Mol Genet Metab. 2000 Sep-Oct;71(1-2):245-9., [PMID:11001817]

Abstract [show]
The R domain of the cystic fibrosis transmembrane conductance regulator (CFTR) was originally defined as 241 amino acids, encoded by exon 13. Such exon/intron boundaries provide a convenient way to define the R domain, but do not necessarily reflect the corresponding functional domain within CFTR. A two-domain model was later proposed based on a comparison of the R-domain sequences from 10 species. While RD1, the N-terminal third of the R domain is highly conserved, RD2, the large central region of the R domain has less rigid structural requirements. Although this two-domain model was given strong support by recent functional analysis data, the simple observation that two of the four main phosphorylation sites are excluded from RD2 clearly indicates that RD2 still does not satisfy the requirements of a "functional R domain." Nevertheless, knowledge of the CFTR structure and function accumulated over the past decade and reevaluated in the context of a comprehensive sequence comparison of 15 CFTR homologues made it possible to define such a "functional R domain," i.e., amino acids C647 to D836. This definition is validated primarily because it contains all of the important potential consensus phosphorylation sequences. In addition, it includes the highly charged motif from E822 to D836. Finally, it includes all of the deletions/insertions in this region. This definition also aids in understanding the effects of missense mutations occurring within this domain.

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47 Conversely, E822K and E826K both change a stringently or well-conserved, negatively charged residue to a positively charged one and therefore would be speculated to produce some functional consequences. Login to comment