Identification of the cyclic-nucleotide-binding domain as a conserved determinant of ion-channel cell-surface localization
| Autor: | Armin Akhavan, Tomohiro Noguchi, Alvin Shrier, Roxana Atanasiu, Natasha Holder, Wei Han |
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| Rok vydání: | 2005 |
| Předmět: |
ERG1 Potassium Channel
Potassium Channels Mutant hERG Molecular Sequence Data Biology medicine.disease_cause Ion Channels Cell Line medicine Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels Humans Amino Acid Sequence Structural motif Loss function Ion channel Genetics Mutation Nucleotides Cell Membrane Cell Biology Potassium channel Ether-A-Go-Go Potassium Channels Cell biology Long QT Syndrome Cyclic nucleotide-binding domain biology.protein Ion Channel Gating Protein Binding |
| Zdroj: | Journal of cell science. 118(Pt 13) |
| ISSN: | 0021-9533 |
| Popis: | Mutations of a putative cyclic-nucleotide-binding domain (CNBD) can disrupt the function of the hyperpolarization-activated cyclic-nucleotide-gated channel (HCN2) and the human ether-a-go-go-related gene potassium channel (HERG). Loss of function caused by C-terminal truncation, which includes all or part of the CNBD in HCN and HERG, has been related to abnormal channel trafficking. Similar defects have been reported for several of the missense mutations of HERG associated with long QT syndrome type 2 (LQT2). Thus, we postulate that normal processing of these channels depends upon the presence of the CNBD. Here, we show that removal of the entire CNBD prevents Golgi transit, surface localization and function of HERG channel tetramers. This is also true when any of the structural motifs of the CNBD is deleted, suggesting that deletion of any highly conserved region along the entire length of the CNBD can disrupt channel trafficking. Furthermore, we demonstrate that defective trafficking is a consequence of all LQT2 mutations in the CNBD, including two mutations not previously assessed and two others for which there are conflicting results in the literature. The trafficking sensitivity of the CNBD might be of general significance for other ion channels because complete deletion of the CNBD or mutations at highly conserved residues within the CNBD of the related ERG3 channel and HCN2 also prevent Golgi transit. These results broadly implicate the CNBD in ion-channel trafficking that accounts for the commonly observed loss of function associated with CNBD mutants and provides a rationale for distinct genetic disorders. |
| Databáze: | OpenAIRE |
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