Membrane-cytoskeleton linker. May participate in the maintenance/targeting of ion channels and cell adhesion molecules at the nodes of Ranvier and axonal initial segments (PubMed:7836469). In skeletal muscle, required for costamere localization of DMD and betaDAG1 (By similarity). Regulates KCNA1 channel activity in function of dietary Mg(2+) levels, and thereby contributes to the regulation of renal Mg(2+) reabsorption (PubMed:23903368). Required for intracellular adhesion and junctional conductance in myocytes, potentially via stabilization of GJA1/CX43 protein abundance and promotion of PKP2, GJA1/CX43, and SCN5A/Nav1.5 localization to cell-cell junctions (By similarity). {ECO:0000250|UniProtKB:G5E8K5, ECO:0000250|UniProtKB:O70511, ECO:0000269|PubMed:23903368, ECO:0000269|PubMed:7836469}. [Isoform 5]: May be part of a Golgi-specific membrane cytoskeleton in association with beta-spectrin. . This is the function of Ensembl gene identifier ENSG00000151150 (ANK3, ankyrin 3).