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Defective potassium currents in ataxia telangiectasia fibroblasts
N Rhodes1, T D'Souza, C D Foster
1Department of Cancer Biology, GlaxoWellcome Research and Development, Research Triangle Park, North Carolina 27709 USA.
Genes & Development
|December 16, 1998
Summary
Ataxia telangiectasia (AT) cells show defective ion channel activity, specifically reduced depolarization and absent outward rectifier K+ currents. Correcting these defects with ATM cDNA highlights ATM
Area of Science:
- Neuroscience
- Cell Biology
- Genetics
Background:
- Progressive cerebellar ataxia in ataxia telangiectasia (AT) shares similarities with other neurodegenerative diseases linked to ion channel dysfunction.
- Investigating ion channel activity in AT cells is crucial for understanding disease mechanisms.
Purpose of the Study:
- To investigate potential defects in ion channel activity within ataxia telangiectasia (AT) cells.
- To determine the role of the ATM gene in regulating ion channel function and membrane potential.
Main Methods:
- Examined membrane potential changes in AT fibroblasts upon extracellular cation addition.
- Performed electrophysiological measurements on AT cell lines and primary fibroblast cultures.
- Assessed the effect of transfecting AT fibroblasts with full-length ATM cDNA.
Main Results:
- AT fibroblasts exhibited significantly reduced depolarization in response to increasing extracellular K+ concentrations compared to control fibroblasts.
- Outward rectifier K+ currents were largely absent in AT fibroblasts.
- Transfection with ATM cDNA corrected the observed K+ current defects in AT fibroblasts.
Conclusions:
- Data implicate the ATM gene in the regulation of K+ channel activity.
- ATM plays a role in maintaining normal membrane potential in fibroblasts.
- Identified a novel function for ATM in ion channel regulation, relevant to neurodegenerative processes.