scholarly journals Cytoskeleton regulators CAPZA2 and INF2 associate with CFTR to control its plasma membrane levels under EPAC1 activation

2020 ◽  
Vol 477 (13) ◽  
pp. 2561-2580
Author(s):  
João D. Santos ◽  
Francisco R. Pinto ◽  
João F. Ferreira ◽  
Margarida D. Amaral ◽  
Manuela Zaccolo ◽  
...  

Cystic Fibrosis (CF), the most common lethal autosomic recessive disorder among Caucasians, is caused by mutations in the gene encoding the Cystic Fibrosis Transmembrane conductance Regulator (CFTR) protein, a cAMP-regulated chloride channel expressed at the apical surface of epithelial cells. Cyclic AMP regulates both CFTR channel gating through a protein kinase A (PKA)-dependent process and plasma membane (PM) stability through activation of the exchange protein directly activated by cAMP1 (EPAC1). This cAMP effector, when activated promotes the NHERF1:CFTR interaction leading to an increase in CFTR at the PM by decreasing its endocytosis. Here, we used protein interaction profiling and bioinformatic analysis to identify proteins that interact with CFTR under EPAC1 activation as possible regulators of this CFTR PM anchoring. We identified an enrichment in cytoskeleton related proteins among which we characterized CAPZA2 and INF2 as regulators of CFTR trafficking to the PM. We found that CAPZA2 promotes wt-CFTR trafficking under EPAC1 activation at the PM whereas reduction of INF2 levels leads to a similar trafficking promotion effect. These results suggest that CAPZA2 is a positive regulator and INF2 a negative one for the increase of CFTR at the PM after an increase of cAMP and concomitant EPAC1 activation. Identifying the specific interactions involving CFTR and elicited by EPAC1 activation provides novel insights into late CFTR trafficking, insertion and/or stabilization at the PM and highlighs new potential therapeutic targets to tackle CF disease.

Impact ◽  
2018 ◽  
Vol 2018 (3) ◽  
pp. 52-54
Author(s):  
Nicolas Lamontagne

Cystic fibrosis (CF) is a progressive life–shortening disease caused by a mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene leading to a dysfunctional CFTR protein. The disease affects over 70,000 patients worldwide and while many mutations are known, the F508del mutation affects 90% of all patients. The absence of CFTR in the plasma membrane leads to a dramatic decrease in chloride efflux, resulting in viscous mucus that causes severe symptoms in vital organs like the lungs and intestines. For CF patients that suffer from the life threatening F508del mutation only palliative treatment exist. PRO–CF–MED addresses the specific challenge of this call by introducing the first disease modifying medication for the treatment of the CF patients with F508del mutation. The PRO–CF–MED project has been designed to assess the potential clinical efficacy of QR–010, an innovative disease modifying oligonucleotide–based treatment for F508del patients. Partners within PRO–CF–MED have generated very promising preclinical evidence for QR–010 which allows for further clinical assessment of QR–010 in clinical trials. PRO–CF–MED will enable the fast translation of QR–010 towards clinical practice and market authorisation. PRO–CF–MED has the potential to transform this life–threatening condition into a manageable one.


Breathe ◽  
2021 ◽  
Vol 17 (4) ◽  
pp. 210112
Author(s):  
Daniel H. Tewkesbury ◽  
Rebecca C. Robey ◽  
Peter J. Barry

The genetic multisystem condition cystic fibrosis (CF) has seen a paradigm shift in therapeutic approaches within the past decade. Since the first clinical descriptions in the 1930s, treatment advances had focused on the downstream consequences of a dysfunctional cystic fibrosis transmembrane conductance regulator (CFTR) chloride ion channel. The discovery of the gene that codes for CFTR and an understanding of the way in which different genetic mutations lead to disruption of normal CFTR function have led to the creation and subsequent licensing of drugs that target this process. This marks an important move towards precision medicine in CF and results from clinical trials and real-world clinical practice have been impressive. In this review we outline how CFTR modulator drugs restore function to the CFTR protein and the progress that is being made in this field. We also describe the real-world impact of CFTR modulators on both pulmonary and multisystem complications of CF and what this will mean for the future of CF care.


2020 ◽  
Vol 21 (2) ◽  
pp. 452 ◽  
Author(s):  
Samuel Estabrooks ◽  
Jeffrey L. Brodsky

Cystic fibrosis (CF) is the most common lethal inherited disease among Caucasians in North America and a significant portion of Europe. The disease arises from one of many mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator, or CFTR. The most common disease-associated allele, F508del, along with several other mutations affect the folding, transport, and stability of CFTR as it transits from the endoplasmic reticulum (ER) to the plasma membrane, where it functions primarily as a chloride channel. Early data demonstrated that F508del CFTR is selected for ER associated degradation (ERAD), a pathway in which misfolded proteins are recognized by ER-associated molecular chaperones, ubiquitinated, and delivered to the proteasome for degradation. Later studies showed that F508del CFTR that is rescued from ERAD and folds can alternatively be selected for enhanced endocytosis and lysosomal degradation. A number of other disease-causing mutations in CFTR also undergo these events. Fortunately, pharmacological modulators of CFTR biogenesis can repair CFTR, permitting its folding, escape from ERAD, and function at the cell surface. In this article, we review the many cellular checkpoints that monitor CFTR biogenesis, discuss the emergence of effective treatments for CF, and highlight future areas of research on the proteostatic control of CFTR.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1677 ◽  
Author(s):  
Shaiq Sultan ◽  
Andrea Rozzi ◽  
Jessica Gasparello ◽  
Alex Manicardi ◽  
Roberto Corradini ◽  
...  

Peptide nucleic acids (PNAs) have been demonstrated to be very useful tools for gene regulation at different levels and with different mechanisms of action. In the last few years the use of PNAs for targeting microRNAs (anti-miRNA PNAs) has provided impressive advancements. In particular, targeting of microRNAs involved in the repression of the expression of the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which is defective in cystic fibrosis (CF), is a key step in the development of new types of treatment protocols. In addition to the anti-miRNA therapeutic strategy, inhibition of miRNA functions can be reached by masking the miRNA binding sites present within the 3′UTR region of the target mRNAs. The objective of this study was to design a PNA masking the binding site of the microRNA miR-145-5p present within the 3′UTR of the CFTR mRNA and to determine its activity in inhibiting miR-145-5p function, with particular focus on the expression of both CFTR mRNA and CFTR protein in Calu-3 cells. The results obtained support the concept that the PNA masking the miR-145-5p binding site of the CFTR mRNA is able to interfere with miR-145-5p biological functions, leading to both an increase of CFTR mRNA and CFTR protein content.


2015 ◽  
Vol 43 (5) ◽  
pp. 894-900 ◽  
Author(s):  
Naomi L. Pollock ◽  
Tracy L. Rimington ◽  
Robert C. Ford

As an ion channel, the cystic fibrosis transmembrane conductance regulator (CFTR) protein occupies a unique niche within the ABC family. Orthologues of CFTR are extant throughout the animal kingdom from sharks to platypods to sheep, where the osmoregulatory function of the protein has been applied to differing lifestyles and diverse organ systems. In humans, loss-of-function mutations to CFTR cause the disease cystic fibrosis, which is a significant health burden in populations of white European descent. Orthologue screening has proved fruitful in the pursuit of high-resolution structural data for several membrane proteins, and we have applied some of the princples developed in previous studies to the expression and purification of CFTR. We have overexpressed this protein, along with evolutionarily diverse orthologues, in Saccharomyces cerevisiae and developed a purification to isolate it in quantities sufficient for structural and functional studies.


2008 ◽  
Vol 413 (1) ◽  
pp. 135-142 ◽  
Author(s):  
Emanuela Caci ◽  
Antonella Caputo ◽  
Alexandre Hinzpeter ◽  
Nicole Arous ◽  
Pascale Fanen ◽  
...  

CFTR (cystic fibrosis transmembrane conductance regulator) is an epithelial Cl− channel inhibited with high affinity and selectivity by the thiazolidinone compound CFTRinh-172. In the present study, we provide evidence that CFTRinh-172 acts directly on the CFTR. We introduced mutations in amino acid residues of the sixth transmembrane helix of the CFTR protein, a domain that has an important role in the formation of the channel pore. Basic and hydrophilic amino acids at positions 334–352 were replaced with alanine residues and the sensitivity to CFTRinh-172 was assessed using functional assays. We found that an arginine-to-alanine change at position 347 reduced the inhibitory potency of CFTRinh-172 by 20–30-fold. Mutagenesis of Arg347 to other amino acids also decreased the inhibitory potency, with aspartate producing near total loss of CFTRinh-172 activity. The results of the present study provide evidence that CFTRinh-172 interacts directly with CFTR, and that Arg347 is important for the interaction.


2003 ◽  
Vol 374 (3) ◽  
pp. 793-797 ◽  
Author(s):  
Mohabir RAMJEESINGH ◽  
Jackie F. KIDD ◽  
Ling Jun HUAN ◽  
Yanchun WANG ◽  
Christine E. BEAR

CFTR (cystic fibrosis transmembrane conductance regulator) mediates chloride conduction across the apical membrane of epithelia, and mutations in CFTR lead to defective epithelial fluid transport. Recently, there has been considerable interest in determining the quaternary structure of CFTR at the cell surface, as such information is a key to understand the molecular basis for pathogenesis in patients harbouring disease-causing mutations. In our previous work [Ramjeesingh, Li, Kogan, Wang, Huan and Bear (2001) Biochemistry 40, 10700–10706], we showed that monomeric CFTR is the minimal functional form of the protein, yet when expressed in Sf 9 cells using the baculovirus system, it also exists as dimers. The purpose of the present study was to determine if dimeric CFTR exists at the surface of mammalian cells, and particularly in epithelial cells. CFTR solubilized from membranes prepared from Chinese-hamster ovary cells stably expressing CFTR and from T84 epithelial cells migrates as predicted for monomeric, dimeric and larger complexes when subjected to sizing by gel filtration and analysis by non-dissociative electrophoresis. Purification of plasma membranes led to the enrichment of CFTR dimers and this structure exists as the complex glycosylated form of the protein, supporting the concept that dimeric CFTR is physiologically relevant. Consistent with its localization in plasma membranes, dimeric CFTR was labelled by surface biotinylation. Furthermore, dimeric CFTR was captured at the apical surface of intact epithelial cells by application of a membrane-impermeable chemical cross-linker. Therefore it follows from the present study that CFTR dimers exist at the surface of epithelial cells. Further studies are necessary to understand the impact of dimerization on the cell biology of wild-type and mutant CFTR proteins.


Author(s):  
E. Elson ◽  
Paula Capel ◽  
Jessica Haynes ◽  
Stephanie Duehlmeyer ◽  
Michelle Fischer ◽  
...  

This report describes a case of a 15-year-old male with cystic fibrosis caused by N1303K and Q493X cystic fibrosis transmembrane conductance regulator (CFTR) protein variants. In this case, CFTR modulators including tezacaftor/ivacaftor and subsequently elexacaftor/tezacaftor/ivacaftor were utilized and resulted in clinical stability and improvement.


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