The voltage-gated sodium channel β2 subunit associates with lipid rafts by S-palmitoylation
- 15 March 2021
- journal article
- research article
- Published by The Company of Biologists in Journal of Cell Science
- Vol. 134 (6)
- https://doi.org/10.1242/jcs.252189
Abstract
The voltage-gated sodium channel is critical for cardiomyocyte function. It consists of a protein complex comprising a pore-forming α subunit and associated β subunits. In polarized Madin-Darby canine kidney cells, we show evidence by acyl-biotin exchange that β2 is S-acylated at Cys-182. Interestingly, we found that palmitoylation increases β2 association with detergent-resistant membranes. β2 localizes exclusively to the apical surface. However, depletion of plasma membrane cholesterol, or blocking intracellular cholesterol transport, caused mislocalization of β2, as well as of the non-palmitoylable C182S mutant, to the basolateral domain. Apical β2 did not undergo endocytosis and displayed limited diffusion within the plane of the membrane, in part behaving as cytoskeleton-anchored. Upon acute cholesterol depletion, its mobility was greatly reduced, and a slight reduction was also measured due to lack of palmitoylation, supporting β2 association with cholesterol-rich lipid rafts. Indeed, lipid raft labeling confirmed a partial overlap with apical β2. Although β2 palmitoylation was not found required to promote surface localization of the α subunit, our data suggest that it is likely implicated in lipid raft association and polarized localization of β2.Keywords
Funding Information
- Fundación Bancaria Caixa d'Estalvis i Pensions de Barcelona
- Fundación Española para la Ciencia y la Tecnología (PR220)
- Agència de Gestió d'Ajuts Universitaris i de Recerca (FI_B 00071)
- Generalitat de Catalunya (FI_B 00071)
- European Social Fund (FI_B 00071)
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