The role of cystic fibrosis transmembrane conductance regulator phenylalanine 508 side chain in ion channel gating

Cui, Liying; Aleksandrov, Luba A.; Hou, Yue Xian; Gentzsch, Martina; Chen, Jey Hsin; Riordan, John R.; Aleksandrov, Andrei A.

doi:10.1113/jphysiol.2005.099457

Cited by 60 publications

(75 citation statements)

References 19 publications

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“…Second, VX-809 decreased the proteolytic sensitivity of full-length F508del-CFTR and the NBD2 fragment of F508del-CFTR, consistent with a more compact protein conformation (12,23,24). Third, the channel gating activity of VX-809-corrected F508del-CFTR was normal, indicating that VX-809 promoted the proper domain-domain interactions previously shown to be essential for normal channel gating (26,28). Fourth, the cell surface stability of VX-809-corrected F508del-CFTR was similar to that of CFTR, suggesting that it was not recognized as defective by the peripheral quality control pathways and degraded (29).…”

Section: Discussionmentioning

confidence: 79%

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Correction of the F508del-CFTR protein processing defect in vitro by the investigational drug VX-809

Goor

Hadida

Grootenhuis

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

973

985

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Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator ( CFTR ) gene that impair the function of CFTR, an epithelial chloride channel required for proper function of the lung, pancreas, and other organs. Most patients with CF carry the F508del CFTR mutation, which causes defective CFTR protein folding and processing in the endoplasmic reticulum, resulting in minimal amounts of CFTR at the cell surface. One strategy to treat these patients is to correct the processing of F508del-CFTR with small molecules. Here we describe the in vitro pharmacology of VX-809, a CFTR corrector that was advanced into clinical development for the treatment of CF. In cultured human bronchial epithelial cells isolated from patients with CF homozygous for F508del, VX-809 improved F508del-CFTR processing in the endoplasmic reticulum and enhanced chloride secretion to approximately 14% of non-CF human bronchial epithelial cells (EC 50 , 81 ± 19 nM), a level associated with mild CF in patients with less disruptive CFTR mutations. F508del-CFTR corrected by VX-809 exhibited biochemical and functional characteristics similar to normal CFTR, including biochemical susceptibility to proteolysis, residence time in the plasma membrane, and single-channel open probability. VX-809 was more efficacious and selective for CFTR than previously reported CFTR correctors. VX-809 represents a class of CFTR corrector that specifically addresses the underlying processing defect in F508del-CFTR.

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Section: Discussionmentioning

confidence: 79%

“…Defects in F508del-CFTR folding have been linked to its impaired channel gating (26)(27)(28). To determine whether correction of F508del-CFTR by VX-809 resulted in CFTR protein with normal channel gating, the channel open probability (P o ) of F508del-CFTR was assessed by using single-channel patch-clamp techniques ( Fig.…”

Section: Resultsmentioning

confidence: 99%

Correction of the F508del-CFTR protein processing defect in vitro by the investigational drug VX-809

Goor

Hadida

Grootenhuis

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

973

985

View full text Add to dashboard Cite

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“…YgfO can also be tagged at its C terminus with a number of different immunodetection and affinity-purification epitopes without affecting the xanthine uptake activity (10). Because analytical evidence on the topology, tertiary structure, binding site, or mechanism of the nucleobase:cation symport is still missing for any NAT, we have taken advantage of the E. coli system to employ Cys-scanning mutagenesis, a strategy that has addressed these problems in many other transport proteins (12)(13)(14)(15)(16)(17)(18). A fully functional version, equivalent to wild-type YgfO, has been constructed, in which all five native Cys residues have been replaced with Ser (Cys-less YgfO).…”

mentioning

confidence: 99%

Cysteine-scanning Analysis of the Nucleobase-Ascorbate Transporter Signature Motif in YgfO Permease of Escherichia coli

Karatza

Panos

Georgopoulou

et al. 2006

Journal of Biological Chemistry

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“…As mutações de classe I estão associadas a um defeito na produção da proteína (proteína ausente); as de classe II estão relacionadas com algum defeito no seu processamento em nível de retículo endoplasmático (RE) ou complexo de Golgi, acarretando um mau dobramento da proteína. O mutante delta F508 (F508) faz parte desta classe; ele não promove uma dobra suficiente para permitir sua saída do RE (5) , e, em consequência, a proteína será degradada dentro da organela ao invés de prosseguir às células secretoras para exercer suas funções (25) . É o defeito mais comum, contribuindo com cerca de 70% de todos os alelos FC nas populações caucasianas (4,5,7,12,17) .…”

Section: O Gene Da Fibrose Cística E Cftrunclassified

Canais Iônicos E Fibrose Cística

Coutinho¹,

Figueiredo²,

Tintino³

et al. 2014

Rev. Interf. FLS

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_________________________________________________________________________________ RESUMOIntrodução: A Fibrose Cística (FC) é uma doença autossômica recessiva letal, que acomete preferencialmente crianças brancas. Objetivo: Descrever e discutir os mecanismos moleculares envolvidos na FC. Materiais e métodos: Artigos obtidos nos bancos de dados internacionais SCIELO, PUBMED, BIOLINE, DOAJ e HIGHWIRE que tratam dos mecanismos moleculares envolvidos na FC. Resultados e discussões: Decorre de mutações no gene que codifica a proteína "regulador de condutância transmembrana da fibrose cística" (CFTR). Esta contribui para a regulação do fluxo iônico nas superfícies apicais das células epiteliais, e é um canal de cloreto. A fisiopatologia da FC envolve o bloqueio da secreção do cloreto através da membrana apical das células epiteliais glandulares, resultando em seu acúmulo intracelular, acompanhado do influxo de sódio e água para este compartimento. Como consequência, ocorre desidratação da superfície celular com formação de secreções espessas -características da doença. O diagnóstico é baseado na clínica, demonstração laboratorial de concentrações elevadas de cloreto no suor e análise genética. O tratamento inclui: fluidificação das vias aéreas, antibioticoterapia, broncodilatadores, suporte nutricional e reposição enzimas. Na tentativa de aumentar o efluxo epitelial de Cl -ou inibir o influxo do Na + , alvos moleculares podem ser atacados por diferentes drogas como reguladores de migração citoplasmática, ativadores da expressão gênica, entre outros, para o primeiro, e inativação dos ENaC (amilorida ou benzamil) ou inibição do influxo de sódio (ouabaína, digoxina ou loperamida). Considerações Finais: Novas modalidades terapêuticas e a detecção precoce da FC por genotipagem podem melhorar o prognóstico e a qualidade de vida dos afetados. Palavras -chave:Fibrose Cística, Canalopatias, CFTR, EnaC, F508. ABSTRACTIntroduction: Cystic Fibrosis (CF) is a lethal autossomic recessive disease occurring mainly in white kids. Objective: Describe and discuss the molecular mechanisms involved in the CF. Material and methods: article obtained from the international databanks SCIELO, PUBMED, BIOLINE, DOAJ and HIGHWIRE about the molecular mechanisms of CF. Results and discussions: Its due mutations on the gene of cystic fibrosis Transmembrane conductance regulator (CFTR). This protein contributes for the regulation of the ionic flow in the apical surfaces of the epithelial cells, and is a chloride canal. The physiopathology of the CF involves the blockade of the chloride secretion through the apical membrane of the epithelial cells, resulting in intracellular accumulation, followed by the sodium and water influx. As consequence will occur a dehidratation of the cellular surface with thick secretion. The diagnosis is based on the clinic, the laboratorial identification of high concentrations of chloride in the sweat and genetic analysis. The treatment includes: rehidratation of the airway, antibiothicotherapy, nutritional support and en...

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The role of cystic fibrosis transmembrane conductance regulator phenylalanine 508 side chain in ion channel gating

Abstract: Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel employing

Cited by 60 publications

References 19 publications

Correction of the F508del-CFTR protein processing defect in vitro by the investigational drug VX-809

Correction of the F508del-CFTR protein processing defect in vitro by the investigational drug VX-809

Cysteine-scanning Analysis of the Nucleobase-Ascorbate Transporter Signature Motif in YgfO Permease of Escherichia coli

Canais Iônicos E Fibrose Cística

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