Mediates the voltage-dependent sodium ion permeability of excitable membranes . Assuming opened or closed conformations in response to the voltage difference across the membrane, the protein forms a sodium-selective channel through which Na(+) ions may pass in accordance with their electrochemical gradient.
In macrophages and melanoma cells, may participate in the control of podosome and invadopodia formation.
Subcellular locations: Cell membrane, Cell projection, Axon
Mainly localizes to the axon initial segment.
Subcellular locations: Cytoplasmic vesicle
Some vesicles are localized adjacent to melanoma invadopodia and macrophage podosomes. Does not localize to the plasma membrane.
Expressed in the hippocampus with increased expression in epileptic tissue compared to normal adjacent tissue (at protein level) . Isoform 5: Expressed in non-neuronal tissues, such as monocytes/macrophages.