scholarly journals Lipid interactions enhance activation and potentiation of cystic fibrosis transmembrane conductance regulator (CFTR)

2018 ◽  
Author(s):  
Stephanie Chin ◽  
Mohabir Ramjeesingh ◽  
Maurita Hung ◽  
June Ereño-Oreba ◽  
Christopher E Ing ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Channel Activation ◽  
Functional Studies ◽  
Cryo Electron Microscopy ◽  
Conduction Pathway ◽  
Cystic Fibrosis Transmembrane ◽  
Anion Conduction ◽  
Detergent Micelles

The recent cryo-electron microscopy structures of phosphorylated, ATP-bound CFTR in detergent micelles failed to reveal an open anion conduction pathway as expected on the basis of previous functional studies in biological membranes. We tested the hypothesis that interaction of CFTR with lipids is important for opening of its channel. Interestingly, molecular dynamics studies revealed that phospholipids associate with regions of CFTR proposed to contribute to its channel activity. More directly, we found that CFTR purified together with associated lipids using the amphipol: A8-35, exhibited higher rates of catalytic activity, channel activation and potentiation using ivacaftor, than did CFTR purified in detergent. Catalytic activity in CFTR detergent micelles was partially rescued by addition of phospholipids plus cholesterol, arguing that these lipids contribute directly to its modulation. In summary, these studies highlight the importance of lipids in regulated CFTR channel activation and potentiation.

scholarly journals Cholesterol Interaction Directly Enhances Intrinsic Activity of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)

Cells ◽  
2019 ◽  
Vol 8 (8) ◽  
pp. 804 ◽  
Author(s):  
Chin ◽  
Ramjeesingh ◽  
Hung ◽  
Ereño-Oreba ◽  
Cui ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Catalytic Activity ◽  
Intrinsic Activity ◽  
Transmembrane Conductance Regulator ◽  
Channel Activity ◽  
Transmembrane Conductance ◽  
Activity Measurements ◽  
Conduction Pathway ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

The recent cryo-electron microscopy structures of zebrafish and the human cystic fibrosis transmembrane conductance regulator (CFTR) provided unprecedented insights into putative mechanisms underlying gating of its anion channel activity. Interestingly, despite predictions based on channel activity measurements in biological membranes, the structure of the detergent purified, phosphorylated, and ATP-bound human CFTR protein did not reveal a stably open conduction pathway. This study tested the hypothesis that the functional properties of the detergent solubilized CFTR protein used for structural determinations are different from those exhibited by CFTR purified under conditions that retain associated lipids native to the membrane. It was found that CFTR purified together with phospholipids and cholesterol using amphipol: A8-35, exhibited higher rates of catalytic activity, phosphorylation dependent channel activation and potentiation by the therapeutic compound, ivacaftor, than did CFTR purified in detergent. The catalytic activity of phosphorylated CFTR detergent micelles was rescued by the addition of phospholipids plus cholesterol, but not by phospholipids alone, arguing for a specific role for cholesterol in modulating this function. In summary, these studies highlight the importance of lipid interactions in the intrinsic activities and pharmacological potentiation of CFTR.

Characterizing diverse orthologues of the cystic fibrosis transmembrane conductance regulator protein for structural studies

2015 ◽  
Vol 43 (5) ◽  
pp. 894-900 ◽  
Author(s):  
Naomi L. Pollock ◽  
Tracy L. Rimington ◽  
Robert C. Ford
Keyword(s):  
Cystic Fibrosis ◽  
Structural Data ◽  
Transmembrane Conductance Regulator ◽  
Loss Of Function ◽  
Transmembrane Conductance ◽  
Functional Studies ◽  
Regulator Protein ◽  
Organ Systems ◽  
Cftr Protein ◽  
Cystic Fibrosis Transmembrane

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.

CLC-0 and CFTR: Chloride Channels Evolved From Transporters

2008 ◽  
Vol 88 (2) ◽  
pp. 351-387 ◽  
Author(s):  
Tsung-Yu Chen ◽  
Tzyh-Chang Hwang
Keyword(s):  
Ion Channels ◽  
Membrane Transport ◽  
Chloride Channels ◽  
Transport Proteins ◽  
Transmembrane Conductance Regulator ◽  
Protein Families ◽  
Transmembrane Conductance ◽  
Functional Studies ◽  
Membrane Transport Proteins ◽  
Cystic Fibrosis Transmembrane

CLC-0 and cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channels play important roles in Cl− transport across cell membranes. These two proteins belong to, respectively, the CLC and ABC transport protein families whose members encompass both ion channels and transporters. Defective function of members in these two protein families causes various hereditary human diseases. Ion channels and transporters were traditionally viewed as distinct entities in membrane transport physiology, but recent discoveries have blurred the line between these two classes of membrane transport proteins. CLC-0 and CFTR can be considered operationally as ligand-gated channels, though binding of the activating ligands appears to be coupled to an irreversible gating cycle driven by an input of free energy. High-resolution crystallographic structures of bacterial CLC proteins and ABC transporters have led us to a better understanding of the gating properties for CLC and CFTR Cl− channels. Furthermore, the joined force between structural and functional studies of these two protein families has offered a unique opportunity to peek into the evolutionary link between ion channels and transporters. A promising byproduct of this exercise is a deeper mechanistic insight into how different transport proteins work at a fundamental level.

CFTR: Mechanism of Anion Conduction

1999 ◽  
Vol 79 (1) ◽  
pp. S47-S75 ◽  
Author(s):  
DAVID C. DAWSON ◽  
STEPHEN S. SMITH ◽  
MONIQUE K. MANSOURA
Keyword(s):  
Anion Binding ◽  
Rate Theory ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Anion Conductance ◽  
Conduction Process ◽  
Physical Forces ◽  
Pore Properties ◽  
Cystic Fibrosis Transmembrane ◽  
Anion Conduction

Dawson, David C., Stephen S. Smith, and Monique K. Mansoura. CFTR: Mechanism of Anion Conduction. Physiol. Rev. 79, Suppl.: S47–S75, 1999. — The purpose of this review is to collect together the results of recent investigations of anion conductance by the cystic fibrosis transmembrane conductance regulator along with some of the basic background that is a prerequisite for developing some physical picture of the conduction process. The review begins with an introduction to the concepts of permeability and conductance and the Nernst-Planck and rate theory models that are used to interpret these parameters. Some of the physical forces that impinge on anion conductance are considered in the context of permeability selectivity and anion binding to proteins. Probes of the conduction process are considered, particularly permeant anions that bind tightly within the pore and block anion flow. Finally, structure-function studies are reviewed in the context of some predictions for the origin of pore properties.

scholarly journals Cystic Fibrosis Transmembrane Conductance Regulator: A Molecular Model Defines the Architecture of the Anion Conduction Path and Locates a “Bottleneck” in the Pore

Biochemistry ◽  
2012 ◽  
Vol 51 (11) ◽  
pp. 2199-2212 ◽  
Author(s):  
Yohei Norimatsu ◽  
Anthony Ivetac ◽  
Christopher Alexander ◽  
John Kirkham ◽  
Nicolette O’Donnell ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Molecular Model ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Conduction Path ◽  
Cystic Fibrosis Transmembrane ◽  
Anion Conduction

scholarly journals Structural identification of a hotspot on CFTR for potentiation

Science ◽  
2019 ◽  
Vol 364 (6446) ◽  
pp. 1184-1188 ◽  
Author(s):  
Fangyu Liu ◽  
Zhe Zhang ◽  
Anat Levit ◽  
Jesper Levring ◽  
Kouki K. Touhara ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Structural Identification ◽  
Investigational Drug ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Region ◽  
Transmembrane Conductance ◽  
Fatal Disease ◽  
Cryo Electron Microscopy ◽  
Therapeutic Compounds ◽  
Cystic Fibrosis Transmembrane

Cystic fibrosis is a fatal disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR). Two main categories of drugs are being developed: correctors that improve folding of CFTR and potentiators that recover the function of CFTR. Here, we report two cryo–electron microscopy structures of human CFTR in complex with potentiators: one with the U.S. Food and Drug Administration (FDA)–approved drug ivacaftor at 3.3-angstrom resolution and the other with an investigational drug, GLPG1837, at 3.2-angstrom resolution. These two drugs, although chemically dissimilar, bind to the same site within the transmembrane region. Mutagenesis suggests that in both cases, hydrogen bonds provided by the protein are important for drug recognition. The molecular details of how ivacaftor and GLPG1837 interact with CFTR may facilitate structure-based optimization of therapeutic compounds.

Der Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) und Sphingolipide regulieren die hypoxisch pulmonale Vasokonstriktion

Pneumologie ◽  
2016 ◽  
Vol 70 (S 01) ◽  
Author(s):  
C Tabeling ◽  
H Yu ◽  
L Wang ◽  
H Ranke ◽  
NM Goldenberg ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Cystic Fibrosis Transmembrane
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