ABCC7 p.Lys1468*
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[hide] Mutations located in exon 24 of the CFTR gene are ... Clin Genet. 2003 Sep;64(3):266-8. Bienvenu T, Viel M, Leroy C, Van Esch H, Fajac I, Dusser D, Hubert D
Mutations located in exon 24 of the CFTR gene are associated with a mild cystic fibrosis phenotype.
Clin Genet. 2003 Sep;64(3):266-8., [PMID:12919146]
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No. Sentence Comment
33 Similarly, in vitro the C-terminally mutant CFTR (K1468X) did not bind to the first PDZ domain of NHERF (6).
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ABCC7 p.Lys1468* 12919146:33:50
status: NEW[hide] NHE-RF1 protein rescues DeltaF508-CFTR function. Am J Physiol Lung Cell Mol Physiol. 2007 May;292(5):L1085-94. Epub 2007 Jan 19. Bossard F, Robay A, Toumaniantz G, Dahimene S, Becq F, Merot J, Gauthier C
NHE-RF1 protein rescues DeltaF508-CFTR function.
Am J Physiol Lung Cell Mol Physiol. 2007 May;292(5):L1085-94. Epub 2007 Jan 19., [PMID:17237149]
Abstract [show]
In cystic fibrosis (CF), the DeltaF508-CFTR anterograde trafficking from the endoplasmic reticulum to the plasma membrane is inefficient. New strategies for increasing the delivery of DeltaF508-CFTR to the apical membranes are thus pathophysiologically relevant targets to study for CF treatment. Recent studies have demonstrated that PDZ-containing proteins play an essential role in determining polarized plasma membrane expression of ionic transporters. In the present study we have hypothesized that the PDZ-containing protein NHE-RF1, which binds to the carboxy terminus of CFTR, rescues DeltaF508-CFTR expression in the apical membrane of epithelial cells. The plasmids encoding DeltaF508-CFTR and NHE-RF1 were intranuclearly injected in A549 or Madin-Darby canine kidney (MDCK) cells, and DeltaF508-CFTR channel activity was functionally assayed using SPQ fluorescent probe. Cells injected with DeltaF508-CFTR alone presented a low chloride channel activity, whereas its coexpression with NHE-RF1 significantly increased both the basal and forskolin-activated chloride conductances. This last effect was lost with DeltaF508-CFTR deleted of its 13 last amino acids or by injection of a specific NHE-RF1 antisense oligonucleotide, but not by NHE-RF1 sense oligonucleotide. Immunocytochemical analysis performed in MDCK cells transiently transfected with DeltaF508-CFTR further revealed that NHE-RF1 specifically determined the apical plasma membrane expression of DeltaF508-CFTR but not that of a trafficking defective mutant potassium channel (KCNQ1). These data demonstrate that the modulation of the expression level of CFTR protein partners, like NHE-RF1, can rescue DeltaF508-CFTR activity.
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61 To construct the ⌬F508-K1468X mutant plasmid, the KpnI/HpaI restriction fragment of the pcDNA3-⌬F508-CFTR plasmid, containing the ⌬F508 mutation, was cloned in frame in pcDNA3-CFTR-K1468X.
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ABCC7 p.Lys1468* 17237149:61:30
status: NEWX
ABCC7 p.Lys1468* 17237149:61:202
status: NEW174 As illustrated in Fig. 7, coexpression of ⌬F508-K1468X-CFTR with NHE-RF1 in MDCK cells did not result in any significant changes in the baseline or the forskolin-stimulated Cl-channel activity.
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ABCC7 p.Lys1468* 17237149:174:55
status: NEW190 Effect of NHE-RF1 overexpression on ⌬F508-K1468X in MDCK cells.
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ABCC7 p.Lys1468* 17237149:190:49
status: NEW191 MDCK cells were microinjected with ⌬F508-K1468X (30 g/ml) and NHE-RF1 (50 g/ml) cDNAs. Membrane permeability to halides (p, in min-1 ) was measured under baseline conditions (open bars) and after application of 10 M Fsk (filled bars).
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ABCC7 p.Lys1468* 17237149:191:48
status: NEW197 Finally, the involvement of PDZ domains in such effect is strongly suggested by the use of ⌬F508-K1468X-CFTR, a ⌬F508 mutant lacking the 13 last amino acids involved in PDZ interaction with NHE-RF1.
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ABCC7 p.Lys1468* 17237149:197:104
status: NEW224 Indeed, ⌬F508-K1468X-CFTR exhibited a low basal Cl-channel activity that was insensitive to forskolin in the presence of NHE-RF1.
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ABCC7 p.Lys1468* 17237149:224:21
status: NEW[hide] A C-terminal motif found in the beta2-adrenergic r... Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8496-501. Hall RA, Ostedgaard LS, Premont RT, Blitzer JT, Rahman N, Welsh MJ, Lefkowitz RJ
A C-terminal motif found in the beta2-adrenergic receptor, P2Y1 receptor and cystic fibrosis transmembrane conductance regulator determines binding to the Na+/H+ exchanger regulatory factor family of PDZ proteins.
Proc Natl Acad Sci U S A. 1998 Jul 21;95(15):8496-501., 1998-07-21 [PMID:9671706]
Abstract [show]
The Na+/H+ exchanger regulatory factor (NHERF) binds to the tail of the beta2-adrenergic receptor and plays a role in adrenergic regulation of Na+/H+ exchange. NHERF contains two PDZ domains, the first of which is required for its interaction with the beta2 receptor. Mutagenesis studies of the beta2 receptor tail revealed that the optimal C-terminal motif for binding to the first PDZ domain of NHERF is D-S/T-x-L, a motif distinct from those recognized by other PDZ domains. The first PDZ domain of NHERF-2, a protein that is 52% identical to NHERF and also known as E3KARP, SIP-1, and TKA-1, exhibits binding preferences very similar to those of the first PDZ domain of NHERF. The delineation of the preferred binding motif for the first PDZ domain of the NHERF family of proteins allows for predictions for other proteins that may interact with NHERF or NHERF-2. For example, as would be predicted from the beta2 receptor tail mutagenesis studies, NHERF binds to the tail of the purinergic P2Y1 receptor, a seven-transmembrane receptor with an intracellular C-terminal tail ending in D-T-S-L. NHERF also binds to the tail of the cystic fibrosis transmembrane conductance regulator, which ends in D-T-R-L. Because the preferred binding motif of the first PDZ domain of the NHERF family of proteins is found at the C termini of a variety of intracellular proteins, NHERF and NHERF-2 may be multifunctional adaptor proteins involved in many previously unsuspected aspects of intracellular signaling.
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No. Sentence Comment
43 The following proteins were in vitro translated by using the TNT system (Promega) in the presence of [35 S]methionine: full-length CFTR-4, CFTR-K1468X, or fusion proteins of CFTR cloned into the pET33b vector (Novagen) (C-terminal amino acids 1387-1480 or N-terminal amino acids 1-80).
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ABCC7 p.Lys1468* 9671706:43:144
status: NEW111 Conversely, neither the N-terminal portion of CFTR nor a C-terminally truncated mutant CFTR (K1468X) exhibited detectable binding to NHERF.
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ABCC7 p.Lys1468* 9671706:111:93
status: NEW163 Full-length CFTR and CFTR C terminus bound avidly to the NHERF but CFTR N terminus and CFTR K1468X did not detectably bind.
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ABCC7 p.Lys1468* 9671706:163:92
status: NEW[hide] NHERF1 and CFTR restore tight junction organisatio... Lab Invest. 2012 Nov;92(11):1527-40. doi: 10.1038/labinvest.2012.123. Epub 2012 Sep 10. Castellani S, Guerra L, Favia M, Di Gioia S, Casavola V, Conese M
NHERF1 and CFTR restore tight junction organisation and function in cystic fibrosis airway epithelial cells: role of ezrin and the RhoA/ROCK pathway.
Lab Invest. 2012 Nov;92(11):1527-40. doi: 10.1038/labinvest.2012.123. Epub 2012 Sep 10., [PMID:22964850]
Abstract [show]
Tight junctions (TJs) restrict the transit of ions and molecules through the paracellular route and act as a barrier to regulate access of inflammatory cells into the airway lumen. The pathophysiology of cystic fibrosis (CF) lung disease is characterised by abnormal ion and fluid transport across the epithelium and polymorphonuclear (PMN) leukocyte-dominated inflammatory response. Na(+)/H(+) exchanger regulatory factor 1 (NHERF1) is a protein involved in PKA-dependent activation of CFTR by interacting with CFTR via its PDZ domains and with ezrin via its C-terminal domain. We have previously found that the NHERF1-overexpression dependent rescue CFTR-dependent chloride secretion is due to the re-organisation of the actin cytoskeleton network induced by the formation of the multiprotein complex NHERF1-RhoA-ezrin-actin. In this context, we here studied whether NHERF1 and CFTR are involved in the organisation and function of TJs. F508del CFBE41o(-) monolayers presented nuclear localisation of zonula occludens (ZO-1) and occludin as well as disorganisation of claudin 1 and junction-associated adhesion molecule 1 as compared with wild-type 16HBE14o(-) monolayers, paralleled by increased permeability to dextrans and PMN transmigration. Overexpression of either NHERF1 or CFTR in CFBE41o(-) cells rescued TJ proteins to their proper intercellular location and decreased permeability and PMN transmigration, while this effect was not achieved by overexpressing either NHERF1 deprived of ezrin-binding domain. Further, expression of a phospho-dead ezrin mutant, T567A, increased permeability in both 16HBE14o(-) cells and in a CFBE clone stably overexpressing NHERF1 (CFBE/sNHERF1), whereas a constitutively active form of ezrin, T567D, achieved the opposite effect in CFBE41o(-) cells. A dominant-negative form of RhoA (RhoA-N19) also disrupted ZO-1 localisation at the intercellular contacts dislodging it to the nucleus and increased permeability in CFBE/sNHERF1. The inhibitor Y27632 of Rho kinase (ROCK) increased permeability as well. Overall, these data suggest a significant role for the multiprotein complex CFTR-NHERF1-ezrin-actin in maintaining TJ organisation and barrier function, and suggest that the RhoA/ROCK pathway is involved.
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34 Wild-type CFTR inserted in pcDNA3.1 was already described.16 CFTR K1468X lacking the 12 C-terminal amino acids,17 inserted into pTM1, was generously provided by Prof. MJ Welsh (University of Iowa, Iowa City, USA).
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ABCC7 p.Lys1468* 22964850:34:66
status: NEW103 Transfection of CFTR-NH2 and K1468X gave no effect on occludin, while in case of claudin 1 and JAM-1 it produced a less pronounced effect than transfection of wild-type CFTR and NHERF1 (Supplementary Figures 2-4).
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ABCC7 p.Lys1468* 22964850:103:29
status: NEW