ABCMdb

ABCC7 p.Met1137Arg

ClinVar:	c.3409A>G , p.Met1137Val ? , not provided c.3410T>G , p.Met1137Arg ? , not provided
CF databases:	c.3409A>G , p.Met1137Val (CFTR1) ? , This mutation (M1137V) in exon 18 of CFTR gene. The nucleotide at position 3541 was changed from A to G leading to a substitution of methionine codon for valine codon at position 1137. The mutation was foudn once in 384 chromsomes (289 CF chromosomes and 95 normal chromosomes) screened. Mutation on the other chromosome of the pancreatic sufficient patient is unknown. c.3410T>C , p.Met1137Thr (CFTR1) ? , The mutation was detected by DGGE analysis and characterized by direct sequencing. We have seen it only twice, in over 1300 control chromosomes from Italian population. c.3410T>G , p.Met1137Arg (CFTR1) ? , The M1137R mutation has been found once in 59 non-[delta]F508 chromosomes from the Portuguese population, associated with haplotype C. The patient carries the F1052V mutation on the other chromosome and presents a mild form of CF. M1137R was found neither in 28 normal chromosomes nor in 31 [delta]F508 CF chromosomes.
Predicted by SNAP2:	A: D (95%), C: D (91%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (85%), K: D (95%), L: D (85%), N: D (95%), P: D (95%), Q: D (95%), R: D (95%), S: D (95%), T: D (95%), V: N (72%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: D, F: N, G: D, H: D, I: N, K: D, L: N, N: D, P: D, Q: D, R: D, S: D, T: D, V: N, W: D, Y: D,

[switch to compact view]
Comments [show]

None has been submitted yet.

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.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
378 M1137R interfered with the proper maturation of the protein and the whole cell cAMP activated chloride currents were reduced for M1137V, I1139V, D1152H and D1154G, indicating that these mutations interfere with the proper gating of chloride channels [180]. Login to comment

[hide] Mechanisms for rescue of correctable folding defec... Mol Biol Cell. 2009 Sep;20(18):4059-69. Epub 2009 Jul 22. Grove DE, Rosser MF, Ren HY, Naren AP, Cyr DM
Mechanisms for rescue of correctable folding defects in CFTRDelta F508.
Mol Biol Cell. 2009 Sep;20(18):4059-69. Epub 2009 Jul 22., [PMID:19625452]

Abstract [show]
Premature degradation of CFTRDeltaF508 causes cystic fibrosis (CF). CFTRDeltaF508 folding defects are conditional and folding correctors are being developed as CF therapeutics. How the cellular environment impacts CFTRDeltaF508 folding efficiency and the identity of CFTRDeltaF508's correctable folding defects is unclear. We report that inactivation of the RMA1 or CHIP ubiquitin ligase permits a pool of CFTRDeltaF508 to escape the endoplasmic reticulum. Combined RMA1 or CHIP inactivation and Corr-4a treatment enhanced CFTRDeltaF508 folding to 3-7-fold greater levels than those elicited by Corr-4a. Some, but not all, folding defects in CFTRDeltaF508 are correctable. CHIP and RMA1 recognize different regions of CFTR and a large pool of nascent CFTRDeltaF508 is ubiquitinated by RMA1 before Corr-4a action. RMA1 recognizes defects in CFTRDeltaF508 related to misassembly of a complex that contains MSD1, NBD1, and the R-domain. Corr-4a acts on CFTRDeltaF508 after MSD2 synthesis and was ineffective at rescue of DeltaF508 dependent folding defects in amino-terminal regions. In contrast, misfolding caused by the rare CF-causing mutation V232D in MSD1 was highly correctable by Corr-4a. Overall, correction of folding defects recognized by RMA1 and/or global modulation of ER quality control has the potential to increase CFTRDeltaF508 folding and provide a therapeutic approach for CF.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
183 Thus, we asked to what extent can disease related folding defects caused by mutations in MSD1 (G85E, G91R, and V232D), MSD2 (M1137R), and NBD2 (N1303K) be corrected relative to those caused by deletion of F508 in NBD1 (Figure 4A). Login to comment
184 The G85E, G91R, M1137R, and N1303K mutations all hinder folding of the nascent B-form of CFTR via a mechanism that involves insertion of a charged amino acid into an inappropriate region (Gregory et al., 1991; Xiong et al., 1997; Vankeerberghen et al., 1998). Login to comment
190 The CFTR M1137R mutation exists within TM12 of CFTR`s MSD2 domain. Login to comment
192 Furthermore, chemical treatment of CFTR G91R or CFTR M1137R did not significantly affect the accumulation of the immature B-form; however, the mature C-forms of both CFTR G91R and CFTR M1137R were apparent. Login to comment
316 Corr-4a-dependent rescue of MSD biogenic mutants G91R and M1137R was no greater than that observed with corrector-treated CFTR⌬F508. Login to comment

[hide] Membrane-integration characteristics of two ABC tr... J Mol Biol. 2009 Apr 17;387(5):1153-64. Epub 2009 Feb 21. Enquist K, Fransson M, Boekel C, Bengtsson I, Geiger K, Lang L, Pettersson A, Johansson S, von Heijne G, Nilsson I
Membrane-integration characteristics of two ABC transporters, CFTR and P-glycoprotein.
J Mol Biol. 2009 Apr 17;387(5):1153-64. Epub 2009 Feb 21., [PMID:19236881]

Abstract [show]
To what extent do corresponding transmembrane helices in related integral membrane proteins have different membrane-insertion characteristics? Here, we compare, side-by-side, the membrane insertion characteristics of the 12 transmembrane helices in the adenosine triphosphate-binding cassette (ABC) transporters, P-glycoprotein (P-gp) and the cystic fibrosis transmembrane conductance regulator (CFTR). Our results show that 10 of the 12 CFTR transmembrane segments can insert independently into the ER membrane. In contrast, only three of the P-gp transmembrane segments are independently stable in the membrane, while the majority depend on the presence of neighboring loops and/or transmembrane segments for efficient insertion. Membrane-insertion characteristics can thus vary widely between related proteins.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
113 For CFTR, we chose mutations located in TM1CFTR (F87L, G91R), TM3CFTR (P205S, L206W), TM4CFTR (C225R), TM5CFTR (DF311, G314E), TM6CFTR (R334L/W, I336K/R/D, I340N/S, L346P, R347L/H), TM8CFTR (S909I, S912L), TM9CFTR (I1005R, A1006E), TM10CFTR (Y1032N), and TM12CFTR (M1137R, ΔM1140, M1140K), or close to the TM region of TM1CFTR (R74W, L102R/P), TMF2CFTR (R117P/L, L137P), and TM11CFTR (M1101K/R). Login to comment
109 For CFTR, we chose mutations located in TM1CFTR (F87L, G91R), TM3CFTR (P205S, L206W), TM4CFTR (C225R), TM5CFTR (DF311, G314E), TM6CFTR (R334L/W, I336K/R/D, I340N/S, L346P, R347L/H), TM8CFTR (S909I, S912L), TM9CFTR (I1005R, A1006E), TM10CFTR (Y1032N), and TM12CFTR (M1137R, ƊM1140, M1140K), or close to the TM region of TM1CFTR (R74W, L102R/P), TMF2CFTR (R117P/L, L137P), and TM11CFTR (M1101K/R). Login to comment

[hide] The K+ channel opener 1-EBIO potentiates residual ... PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31. Roth EK, Hirtz S, Duerr J, Wenning D, Eichler I, Seydewitz HH, Amaral MD, Mall MA
The K+ channel opener 1-EBIO potentiates residual function of mutant CFTR in rectal biopsies from cystic fibrosis patients.
PLoS One. 2011;6(8):e24445. Epub 2011 Aug 31., [PMID:21909392]

Abstract [show]
BACKGROUND: The identification of strategies to improve mutant CFTR function remains a key priority in the development of new treatments for cystic fibrosis (CF). Previous studies demonstrated that the K(+) channel opener 1-ethyl-2-benzimidazolone (1-EBIO) potentiates CFTR-mediated Cl(-) secretion in cultured cells and mouse colon. However, the effects of 1-EBIO on wild-type and mutant CFTR function in native human colonic tissues remain unknown. METHODS: We studied the effects of 1-EBIO on CFTR-mediated Cl(-) secretion in rectal biopsies from 47 CF patients carrying a wide spectrum of CFTR mutations and 57 age-matched controls. Rectal tissues were mounted in perfused micro-Ussing chambers and the effects of 1-EBIO were compared in control tissues, CF tissues expressing residual CFTR function and CF tissues with no detectable Cl(-) secretion. RESULTS: Studies in control tissues demonstrate that 1-EBIO activated CFTR-mediated Cl(-) secretion in the absence of cAMP-mediated stimulation and potentiated cAMP-induced Cl(-) secretion by 39.2+/-6.7% (P<0.001) via activation of basolateral Ca(2)(+)-activated and clotrimazole-sensitive KCNN4 K(+) channels. In CF specimens, 1-EBIO potentiated cAMP-induced Cl(-) secretion in tissues with residual CFTR function by 44.4+/-11.5% (P<0.001), but had no effect on tissues lacking CFTR-mediated Cl(-) conductance. CONCLUSIONS: We conclude that 1-EBIO potentiates Cl(-)secretion in native CF tissues expressing CFTR mutants with residual Cl(-) channel function by activation of basolateral KCNN4 K(+) channels that increase the driving force for luminal Cl(-) exit. This mechanism may augment effects of CFTR correctors and potentiators that increase the number and/or activity of mutant CFTR channels at the cell surface and suggests KCNN4 as a therapeutic target for CF.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
46 CFabsent CFresidual CFTR genotype Number of individuals CFTR genotype Number of individuals F508del/F508del 10 F508del/Y161C 1 F508del/W57X 1 F508del/V232D 1 F508del/G85E 3 F508del/R334W 2 F508del/120del23 1 F508del/T338I 1 F508del/182delT 1 F508del/I1234V 1 F508del/G542X 1 F508del/3272-26 A.G 1 F508del/A561E 1 F508del/3849+10 kb C.T 1 F508del/Y1092X 1 F508del/4005 +5727 A.G 1 F508del/N1303K 1 F508del/G576A 1 F508del/1525-1 G.A 2 N1303K/R334W 1 F508del/Q39X 1 F1052V/M1137R 1 F508del/Q552X 1 1898+3 A.G/ 1898+3 A.G 1 G85E/G85E 1 R334W/3199del6 1 Q552X/R1162X 1 R334W/X 1 A561E/A561E 2 dele2,3/X 1 R764X/1717-1 G.A 1 R1158X/2183AA.G 1 R1158X/R560T 1 doi:10.1371/journal.pone.0024445.t001 luminal and basolateral surfaces of the epithelium were perfused continuously with a solution of the following composition (mmol/ L): NaCl 145, KH2PO4 0.4, K2HPO4 1.6, D-glucose 5, MgCl2 1, Ca-gluconate 1.3, pH 7.4, at 37uC. Login to comment

[hide] Multiplex ligation-dependent probe amplification i... J Mol Diagn. 2008 Jul;10(4):368-75. Epub 2008 Jun 13. Schrijver I, Rappahahn K, Pique L, Kharrazi M, Wong LJ
Multiplex ligation-dependent probe amplification identification of whole exon and single nucleotide deletions in the CFTR gene of Hispanic individuals with cystic fibrosis.
J Mol Diagn. 2008 Jul;10(4):368-75. Epub 2008 Jun 13., [PMID:18556774]

Abstract [show]
A disparity between Caucasian and Hispanic mutation detection for cystic fibrosis continues to exist, although the carrier frequency is only moderately lower in Hispanics. We aimed to identify exonic rearrangements that remained undetected by conventional methods. In seven of 32 cystic fibrosis-affected self-identified Hispanics for whom only one or no mutations were identified by extensive molecular testing, exon deletions appeared to be present with a multiplex ligation-dependent probe amplification (MLPA) assay. Two recurrent deletions (of exons 2-3 and exons 22-23) were identified in one and three patients, respectively (12.5%, 11.1% of unidentified alleles). Two apparently novel deletions (exons 6b and 20) were identified in three additional patients. Subsequent sequencing to characterize deletion breakpoints, however, identified single nucleotide deletions at the probe binding sites close to the ligation point. All resulted in false positive MLPA deletion signals. Interestingly, these mutations were not common in Caucasians, and one (935delA) was common in U.S. Hispanics. On examination of all probe binding sites, we identified a total of 76 reported mutations and five silent variants that immediately surrounded the MLPA ligation sites, with 22 occurring in non-Caucasians. These mutations are not all rare. Thus, apparent exon deletions by MLPA may indicate the presence of both large deletions and point mutations, with important implications for pan-ethnic MLPA testing in cystic fibrosis and other genetic conditions.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
112 Mutations under MLPA Ligation Sites Exon Probe length (nt) Ligation site sequence Mutations in area of ligation site sequence* 1,5Ј UTR 154 5Ј-GAGCAAAT-TTGGGGCC-3Ј N/A 1,5Ј UTR 238 5Ј-AAAGGGTT-GAGCGGCA-3Ј 2 198 5Ј-TTGGTATA-TGTCTGAC-3Ј (5) 3 136 5Ј-CTGCTAGT-GTTGCCAA-3Ј (3) 3 220 5Ј-TTCAAAGA-AAAATCCT-3Ј 4 247 5Ј-AGAATCAT-AGCTTCCT-3Ј 444delA, African; 451del8, Chinese; (6) 5 346 5Ј-AAATAAGT-ATTGGACA-3Ј Q179K, Hispanic (7) 6a 274 5Ј-GAGTTGTT-ACAGGCGT-3Ј L218X, Pakistani (4) 6b 301 5Ј-ATTTTCAA-TCATTTCT-3Ј 935delA, Hispanic; 936delTA, Hispanic (3) 7 337 5Ј-ACTTCAAT-AGCTCAGC-3Ј S307N, Turkish (9) 8, IVS 8 364 5Ј-TTTCTAGA-TTAAGAAG-3Ј N/A 9, IVS 8 391 5Ј-TCCATCAC-ACTGGTAG-3Ј N/A 10 463 5Ј-TCCACTGT-GCTTAATT-3Ј H484Y, Hispanic; S485C, Chinese-Caucasian (5) 11 418 5Ј-CAGAGAAA-GACAATAT-3Ј K536X, Iranian; 1742delAC, Japanese (5) 12, IVS 12 292 5Ј-TGCATTTT-ACCTCTTG-3Ј N/A 13 142 5Ј-CAGATTCT-GAGCAGGG-3Ј (1) 14a 160 5Ј-GTATGTGT-TCCATGTA-3Ј (3) 14b 178 5Ј-CTGCTTCT-TTGGTTGT-3Ј 2766del8, Tunisian (1) 15 204 5Ј-GCTTGCTA-TGGGATTC-3Ј (1) 16, IVS 16 229 5Ј-GATGTAAT-AGCTGTCT-3Ј N/A 17a 256 5Ј-TGCAACAA-AGATGTAG-3Ј 3171delC, Hispanic; 3173delAC, Turkish; F1016S, Hispanic (5) 17b 283 5Ј-CAGTATGT-AAATTCAG-3Ј H1085R, Japanese (4) 18 310 5Ј-CCATGAAT-ATCATGAG-3Ј M1137R, Hispanic (6) 19 353 5Ј-TCTGTGTA-TTTTGCTG-3Ј 3791delC, African-American (2) 20 382 5Ј-CTTGGGAT-TCAATAAC-3Ј 3960delA, Hispanic (2) 21 409 5Ј-TGCAACTT-TCCATATT-3Ј W1316X, African-American (2) 22 436 5Ј-GAACAGTT-TCCTGGGA-3Ј No mutations 23 148 5Ј-CCAGCATT-GCTTCTAT-3Ј M1407T, Turkish; E1409K, Hispanic (2) 24 190 5Ј-ATCCAGAA-ACTGCTGA-3Ј No mutations 24 172 5Ј-CTCCTCTT-TCAGAGCA-3Ј UTR, untranslated region; IVS, intervening sequence; N/A, not applicable, probes not in coding region; No mutations, no reported mutations are present in the area of the ligation site sequence, regardless of ethnicity. Login to comment

[hide] CFTR Cl- channel function in native human colon co... Gastroenterology. 2004 Oct;127(4):1085-95. Hirtz S, Gonska T, Seydewitz HH, Thomas J, Greiner P, Kuehr J, Brandis M, Eichler I, Rocha H, Lopes AI, Barreto C, Ramalho A, Amaral MD, Kunzelmann K, Mall M
CFTR Cl- channel function in native human colon correlates with the genotype and phenotype in cystic fibrosis.
Gastroenterology. 2004 Oct;127(4):1085-95., [PMID:15480987]

Abstract [show]
BACKGROUND & AIMS: Cystic fibrosis (CF) is caused by over 1000 mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene and presents with a widely variable phenotype. Genotype-phenotype studies identified CFTR mutations that were associated with pancreatic sufficiency (PS). Residual Cl- channel function was shown for selected PS mutations in heterologous cells. However, the functional consequences of most CFTR mutations in native epithelia are not well established. METHODS: To elucidate the relationships between epithelial CFTR function, CFTR genotype, and patient phenotype, we measured cyclic adenosine monophosphate (cAMP)-mediated Cl- secretion in rectal biopsy specimens from 45 CF patients who had at least 1 non-DeltaF508 mutation carrying a wide spectrum of CFTR mutations. We compared CFTR genotypes and clinical manifestations of CF patients who expressed residual CFTR-mediated Cl- secretion with patients in whom Cl- secretion was absent. RESULTS: Residual anion secretion was detected in 40% of CF patients, and was associated with later disease onset (P < 0.0001), higher frequency of PS (P < 0.0001), and less severe lung disease (P < 0.05). Clinical outcomes correlated with the magnitude of residual CFTR activity, which was in the range of approximately 12%-54% of controls. CONCLUSIONS: Specific CFTR mutations confer residual CFTR function to rectal epithelia, which is related closely to a mild disease phenotype. Quantification of rectal CFTR-mediated Cl- secretion may be a sensitive test to predict the prognosis of CF disease and identify CF patients who would benefit from therapeutic strategies that would increase residual CFTR activity.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
78 Relationship Between the CFTR Genotype and Cl- Channel Function in Native Rectal Epithelia CFTR genotype Number of individuals Sweat Cl-concentration (mmol/L)a cAMP-mediated response Carbachol-induced plateau response or maximal lumen-negative response Isc-cAMP (␮A/cm2) Cl- secretion (% of control) Isc-carbachol (␮A/cm2) Cl- secretion (% of control) Cl- secretion absent R1162X/Q552X 1 71 17.1 0 0.7 0 W1282X/3121-2AϾG 1 112 1.9 0 0.6 0 1898 ϩ 1G Ͼ T/1609delCA 2b 114, 118 25.4, 13.4 0, 0 0, 0.7 0, 0 ⌬F508/Q39X 2b 127, 129 2.6, 4.4 0, 0 1.7, 3.7 0, 0 ⌬F508/G542X 1 102 29.0 0 6.6 0 ⌬F508/R553X 3 112, 102, 109 13.1, 4.5, 23.8 0, 0, 0 1.5, 4.4, 1.0 0, 0, 0 ⌬F508/E585X 1 115 1.4 0 1.1 0 ⌬F508/Q637X 1 100 2.9 0 1.2 0 ⌬F508/Y1092X 1 119 0.0 0 -0.3 0 ⌬F508/120del23c 1 72 20.1 0 3.3 0 ⌬F508/182delT 1 116 10.8 0 5.2 0 ⌬F508/3905insT 2 88, 96 8.4, 5.6 0, 0 2.3, -1.1 0, 1 ⌬F508/V520F 1 68 1.2 0 1.7 0 ⌬F508/A561E 3 113, 146, 100 17.0, 17.0, 16.0 0, 0, 0 2.1, 1.5, 3.7 0, 0, 0 ⌬F508/R1066C 1 138 0.0 0 0.0 0 ⌬F508/N1303K 3 100, 117, 94 1.7, 4.1, 1.5 0, 0, 0 -0.6, 2.2, 0.8 0, 0, 0 A561E/A561E 2 101, 116 6.6, 2.0 0, 0 7.3, 3.3 0, 0 Residual Cl- secretiond G542X/I148N 1 75 -50.1 54 -22.2 12 1898 ϩ 3A Ͼ G/1898 ϩ 3A Ͼ G 1 82 -36.8 39 -12.9 7 ⌬F508/3272-26A Ͼ G 1 116 -17.8 19 -27.2 14 ⌬F508/S108F 1 118 -15.8 17 -12.3 7 ⌬F508/R117H 1 90 -35.9 38 -207.7 109 ⌬F508/Y161Cc 1 44 -35.1 37 -45.9 25 ⌬F508/P205S 1 80 -23.3 25 -10.4 5 ⌬F508/V232D 1 120 -16.9 18 -26.9 14 ⌬F508/R334W 1 92 -22.1 23 -21.1 11 ⌬F508/R334W 1 101 -24.5 26 -37.4 20 ⌬F508/T338I 1 73 -44.4 47 -79.4 42 ⌬F508/G576A 1 40 -16.9 18 -115.5 61 ⌬F508/I1234V 1 113 -13.6 15 -8.6 5 G576A/G85E 1 95 -26.1 28 -61.6 32 F1052V/M1137R 1 47 -36.7 39 -146.6 77 M1101K/M1101K 1 94 -11.1 12 -4.8 3 S1159F/S1159F 1 67 -47.9 51 -38.7 21 N1303K/R334W 1 91 -30.3 32 -47.7 25 NOTE. CFTR Cl- channel function was determined in rectal epithelia from Cl- secretory responses induced by IBMX/forskolin (Isc-cAMP) and after co-activation with carbachol (Isc-carbachol). Login to comment
101 Functional Classification and Protein Location of CFTR Mutations Mutation type Severe mutations (protein location) Mild mutations (protein location) Missense V520F, A561E (NBD1) G85E (MSD1, TM1) R1066C (MSD2, CL4) S108F, R117H (MSD1, EL1) N1303K (NBD2) I148N, Y161Ca (MSD1, CL1) P205S (MSD1, TM3) V232D (MSD1, TM4) R334W, T338I (MSD1, TM6) G576A (NBD1) I1234V (NBD2) F1052V, M1101K (MSD2, CL4) M1137R (MSD2, TM12) S1159F (pre-NBD2) Splice 1898 ϩ 1G Ͼ T (R domain) 1898 ϩ 3A Ͼ G (R domain) 3121-2A Ͼ G (MSD2, TM9) 3272-26A Ͼ G (MSD2, TM10) Single amino acid deletion ⌬F508 (NBD1) Nonsense Q39X (N-terminus) G542X, Q552X, R553X, E585X (NBD1) Q637X (R domain) Y1092X (MSD2, CL4) R1162X (pre-NBD2) W1282X (NBD2) Frameshift 120del23a 182delT (N-terminus) 1609delCA (NBD1) 3905insT (NBD2) NOTE. Severe mutation, Cl- secretion absent; mild mutation, residual cAMP-mediated Cl- secretion. Login to comment
123 Residual function also was observed for mutants, which are expected to form membrane Cl- channels that are reduced in number, either owing to improper protein maturation (P205S, M1137R) or owing to reduced levels of full-length CFTR messenger RNA (3272-26AϾG, G576A).32,38 - 40 The only exception was M1101K, which was reported as a loss of function mutation in heterologous cells34 and was associated with residual CFTR function in the 1 homozygous patient studied (Table 1). Login to comment

[hide] Characterization of mutations located in exon 18 o... FEBS Lett. 1998 Oct 16;437(1-2):1-4. Vankeerberghen A, Wei L, Teng H, Jaspers M, Cassiman JJ, Nilius B, Cuppens H
Characterization of mutations located in exon 18 of the CFTR gene.
FEBS Lett. 1998 Oct 16;437(1-2):1-4., [PMID:9804160]

Abstract [show]
In order to get a better insight into the function of amino acid residues located in the second transmembrane domain of the cystic fibrosis transmembrane conductance regulator (CFTR) protein, all exon 18 mutations found in cystic fibrosis (CF) patients were characterized at the protein and at the electrophysiological level. Of the different mutations present in transmembrane helix 12 (M1137V, M1137R, I11139V and deltaM1140), and the intracytoplasmic loop connecting TM12 and NBD2 (D1152H and D1154G), only M1137R interfered with the proper maturation of the protein. Permeability studies performed after injection of the different wild-type and mutant cRNAs in Xenopus laevis oocytes indicated that the mutations did not alter the permeability sequence of the CFTR channels. The whole cell cAMP activated chloride currents, however, were significantly reduced for M1137V, I1139V, D1152H and D1154G and close to zero for deltaM1140, indicating that these mutations interfere with the proper gating of the chloride channels.

Comments [show]

None has been submitted yet.

Sentences [show]
No. Sentence Comment
1 Of the different mutations present in transmembrane helix 12 (M1137V, M1137R, I1139V and vvM1140), and the intracytoplasmic loop connecting TM12 and NBD2 (D1152H and D1154G), only M1137R interfered with the proper maturation of the protein. Login to comment
31 Six di¡erent mutations: a3541g ( = M1137V), t3542g ( = M1137R), a3547g ( = I1139V), deletion of atg from 3550 ( = vM1140), g3586c ( = D1152H) and a3593g ( = D1154G) were introduced using the Transformer Site-Directed Mutagenesis kit (Clontech). Login to comment
67 Fig. 1 shows that the di¡erent mutants, except M1137R, exhibit the same maturation pattern as wild-type CFTR. Login to comment
68 For M1137R, however, only the 150-kDa form was detected, even after 3 h and 30 min of chase time. Login to comment
69 This indicates that the core glycosylated M1137R translation product is degraded in the ER before it can be transported to the cell surface. Login to comment
78 COS1 cells transfected with wild-type, M1137V, M1137R, I1139V, vM1140, D1152H and D1154G CFTR were metabolically labelled, chased, CFTR was immunoprecipitated and separated on an SDS-PAGE gel. Login to comment
80 M1137V, M1137R, I1139V and vM1140 are located in transmembrane helix 12 and D1152H and D1154G are located in the intracytoplasmic loop connecting TM12 and NBD. Login to comment
83 Four mutants, M1137V, I1139V, D1152H and D1154G showed a signi'cantly reduced current, when compared to wild type, and two other mutants, M1137R and vM1140 were not activated by cAMP (Fig. 3). Login to comment
84 The absence of cAMP sensitive chloride currents found for M1137R is most probably caused by a defect in maturation, as found in COS1 cells. Login to comment
94 One mutation (M1137R) did result in failure of protein maturation while the remainder did a¡ect gating of the chloride channel. Login to comment
66 Fig. 1 shows that the di&#a1;erent mutants, except M1137R, exhibit the same maturation pattern as wild-type CFTR. Login to comment
77 COS1 cells transfected with wild-type, M1137V, M1137R, I1139V, vM1140, D1152H and D1154G CFTR were metabolically labelled, chased, CFTR was immunoprecipitated and separated on an SDS-PAGE gel. Login to comment
79 M1137V, M1137R, I1139V and vM1140 are located in transmembrane helix 12 and D1152H and D1154G are located in the intracytoplasmic loop connecting TM12 and NBD2. Login to comment
82 Four mutants, M1137V, I1139V, D1152H and D1154G showed a signi'cantly reduced current, when compared to wild type, and two other mutants, M1137R and vM1140 were not activated by cAMP (Fig. 3). Login to comment
93 One mutation (M1137R) did result in failure of protein maturation while the remainder did a&#a1;ect gating of the chloride channel. Login to comment