Mutation of R555 in CFTR-delta F508 enhances function and partially corrects defective processing

J L Teem; M R Carson; M J Welsh

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Mutation of R555 in CFTR-delta F508 enhances function and partially corrects defective processing

Journal article

Peer reviewed

Mutation of R555 in CFTR-delta F508 enhances function and partially corrects defective processing

J L Teem, M R Carson and M J Welsh

Receptors & channels, Vol.4(1), pp.63-72

1996

PMID: 8723647

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Abstract

The most common cystic fibrosis mutation deletes phenylalanine 508 in CFTR (CFTR-F508). This mutation causes the loss of CFTR Cl- channel activity by disrupting biosynthetic processing so that mutant protein does not reach the plasma membrane. It also decreases the rate at which mutant channels open. To identify second-site mutations that could reverse the effects of delta F508, we used a chimeric yeast STE6/CFTR system bearing the delta F508 mutation. This chimera manifests defective mating. After mutagenesis of the first nucleotide-binding domain, we found that mutation R555K partially restored mating. However, it also increased mating in the chimera lacking the delta F508 mutation. When we introduced the R555K mutation into human CFTR-delta F508, we found that the loss of apical Cl- current caused by delta F508 was partially restored, predominantly due to a partial correction of the delta F508 processing defect. Analysis of single CFTR Cl- channels showed that the R555K mutation did not correct the prolonged closed time associated with delta F508, rather it increased activity of both wild-type and delta F508 channels by prolonging the duration of bursts of activity. These data suggest that the region around residue R555 in the first nucleotide-binding domain is important both in determining the ability of the delta F508 protein to be properly processed and in determining channel function.

Amino Acid Sequence

Arginine - physiology

Mutagenesis, Site-Directed

Humans

Protein Processing, Post-Translational - genetics

Cystic Fibrosis Transmembrane Conductance Regulator - physiology

Molecular Sequence Data

Electric Conductivity

Fungal Proteins - genetics

Lysine - physiology

Recombinant Fusion Proteins

Cyclic AMP - physiology

Yeasts - genetics

Yeasts - physiology

Ion Channel Gating - physiology

ATP-Binding Cassette Transporters - genetics

Cystic Fibrosis - genetics

ATP-Binding Cassette Transporters - metabolism

Cystic Fibrosis Transmembrane Conductance Regulator - genetics

Cyclic AMP - agonists

Fungal Proteins - metabolism

Suppression, Genetic

Details

Title: Subtitle: Mutation of R555 in CFTR-delta F508 enhances function and partially corrects defective processing
Creators: J L Teem - University of Iowa College of Medicine, Department of Internal Medicine, Iowa City 52242, USA
M R Carson
M J Welsh
Resource Type: Journal article
Publication Details: Receptors & channels, Vol.4(1), pp.63-72
Publisher: England
PMID: 8723647
ISSN: 1060-6823
eISSN: 1607-856X
Language: English
Date published: 1996
Academic Unit: Neurology; Molecular Physiology and Biophysics; Neurosurgery; Internal Medicine
Record Identifier: 9984020707302771

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63 Times Cited - Web of Science