Ankyrin G is found in several tissues including brain where, due to tissue-specific RNA processing, it is expressed as two different isoforms, localized to axon initial segments and nodes of Ranvier. Ankyrin G is also found at sites of epithelial cell- cell contact and in the intracellular membranes of some cells. Ankyrin G isoforms contain a unique stretch of sequence highly enriched in serine and threonine residues immediately following a globular head domain. Ankyrin G is thought to participate in the maintenance and targeting of ion channels and cell adhesion molecules to the nodes of Ranvier and to axon initial segments.