The Binding Site for Channel Blockers That Rescue Misprocessed Human Long QT Syndrome Type 2 ether-a-gogo-related Gene (HERG) Mutations

Autor: Shuxia Zhao, Arthur M. Brown, Eckhard Ficker, Carlos A. Obejero-Paz
Rok vydání: 2002
Předmět:
ERG1 Potassium Channel
Protein Folding
Patch-Clamp Techniques
Potassium Channels
Pyridines
Mutant
Pharmacology
medicine.disease_cause
Biochemistry
Piperidines
Cation Transport Proteins
Cisapride
Mutation
biology
Quinidine
Cell biology
DNA-Binding Proteins
Electrophysiology
Long QT Syndrome
Potassium Channels
Voltage-Gated

Histamine H1 Antagonists
Anti-Arrhythmia Agents
congenital
hereditary
and neonatal diseases and abnormalities

Long QT syndrome
Blotting
Western

hERG
Cell Line
Inhibitory Concentration 50
Structure-Activity Relationship
Gastrointestinal Agents
Transcriptional Regulator ERG
medicine
Humans
Channel blocker
cardiovascular diseases
Binding site
Molecular Biology
Ions
Binding Sites
Dose-Response Relationship
Drug

Endoplasmic reticulum
Cell Membrane
Wild type
Cell Biology
Astemizole
medicine.disease
Ether-A-Go-Go Potassium Channels
Quaternary Ammonium Compounds
Models
Chemical

Mutagenesis
Site-Directed

Trans-Activators
biology.protein
Benzimidazoles
Zdroj: Journal of Biological Chemistry. 277:4989-4998
ISSN: 0021-9258
DOI: 10.1074/jbc.m107345200
Popis: Mutations in the human ether-a-gogo-related gene (HERG) K(+) channel gene cause chromosome 7-linked long QT syndrome type 2 (LQT2), which is characterized by a prolonged QT interval in the electrocardiogram and an increased susceptibility to life-threatening cardiac arrhythmias. LQT2 mutations produce loss-of-function phenotypes and reduce I(Kr) currents either by the heteromeric assembly of non- or malfunctioning channel subunits with wild type subunits at the cell surface or by retention of misprocessed mutant HERG channels in the endoplasmic reticulum. Misprocessed mutations often encode for channel proteins that are functional upon incorporation into the plasma membrane. As a result the pharmacological correction of folding defects and restoration of protein function are of considerable interest. Here we report that the trafficking-deficient pore mutation HERG G601S was rescued by a series of HERG channel blockers that increased cell surface expression. Rescue by these pharmacological chaperones varied directly with their blocking potency. We used structure-activity relationships and site-directed mutagenesis to define the binding site of the pharmacological chaperones. We found that binding occurred in the inner cavity and correlated with hydrophobicity and cationic charge. Rescue was domain-restricted because the trafficking of two misprocessed mutations in the C terminus, HERG F805C and HERG R823W, was not restored by channel blockers. Our findings represent a first step toward the design of pharmacological chaperones that will rescue HERG K(+) channels without block.
Databáze: OpenAIRE