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Ankyrin and spectrin associate with voltage-dependent sodium channels in brain
Y Srinivasan1, L Elmer, J Davis
1Department of Physiology and Molecular Biophysics, Baylor College of Medicine, Houston, Texas 77030.
Nature
|May 12, 1988
Summary
Brain ankyrin links voltage-dependent sodium channels to the neuronal cytoskeleton, controlling their mobility and distribution. This interaction is vital for action potential propagation and neuronal function.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Voltage-dependent sodium channels are essential for action potential propagation.
- Sodium channel mobility is restricted at specific neuronal sites like the axon hillock.
- Mechanisms regulating sodium channel distribution and movement are not fully understood.
Purpose of the Study:
- To identify brain proteins that associate with voltage-dependent sodium channels.
- To elucidate the role of these proteins in regulating sodium channel localization and mobility.
Main Methods:
- Sodium channels were labeled with 3H-saxitoxin (STX) and precipitated using anti-ankyrin antibodies.
- 125I-labeled ankyrin binding to sodium channels reconstituted in lipid vesicles was assessed.
- Competition assays were performed using the cytoplasmic domain of the erythrocyte anion transporter.
Main Results:
- Brain ankyrin specifically associates with voltage-dependent sodium channels.
- Ankyrin binds with high affinity to sodium channels, suggesting a direct interaction.
- The interaction is specific, as other neuronal receptors like GABA and DHP receptors do not bind ankyrin.
Conclusions:
- Brain ankyrin acts as a molecular linker, connecting sodium channels to the neuronal cytoskeleton.
- This ankyrin-mediated linkage is proposed to maintain neuronal membrane heterogeneity.
- The findings suggest ankyrin plays a critical role in controlling sodium channel mobility and function.
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