Na+ channels get anchored ... with a little help

Neurons have high densities of voltage-gated Na+ channels that are restricted to axon initial segments and nodes of Ranvier, where they are responsible for initiating and propagating action potentials. New findings (Brechet, A., M.-P. Fache, A. Brachet, G. Ferracci, A. Baude, M. Irondelle, S. Pereira, C. Leterrier, and B. Dargent. 2008. J. Cell Biol. 183: 1101-1114) reveal that phosphorylation of several key serine residues by the protein kinase CK2 regulates Na+ channel interactions with ankyrin G. The presence of CK2 at the axon initial segment and nodes of Ranvier provides a mechanism to regulate the specific accumulation and retention of Na+ channels within these important domains.