Ankyrins contain four functional domains: an N-terminal domain that contains 24 tandem ankyrin repeats, a central domain that binds to spectrin, a death domain that binds to proteins involved in apoptosis, and a C-terminal regulatory domain that is highly variable between different ankyrin proteins.
The ANK1 gene encodes the AnkyrinR proteins. AnkyrinR was first characterized in human erythrocytes, where this ankyrin was referred to as erythrocyte ankyrin or band2.1. AnkyrinR enables erythrocytes to resist shear forces experienced in the circulation. Individuals with reduced or defective ankyrinR have a form of hemolytic anemia termed hereditary spherocytosis. In erythrocytes, AnkyrinR links the membrane skeleton to the Cl-/HCO3- anion exchanger.
Subsequently, ankyrinB proteins (products of the ANK2 gene) were identified in brain and muscle. AnkyrinB and AnkyrinG proteins are required for the polarized distribution of many membrane proteins including the Na+/K+ ATPase, the voltage gated Na+ channel and the Na+/Ca2+ exchanger.
AnkyrinG proteins (products of the ANK3 gene) were identified in epithelial cells and neurons. A large-scale genetic analysis conducted in 2008 shows the possibility that ANK3 is involved in the bipolar disorder.
^Lux SE, Tse WT, Menninger JC, John KM, Harris P, Shalev O, Chilcote RR, Marchesi SL, Watkins PC, Bennett V (1990). "Hereditary spherocytosis associated with deletion of human erythrocyte ankyrin gene on chromosome 8". Nature345 (6277): 736–9. doi:10.1038/345736a0. PMID2141669.
^Bennett V, Stenbuck PJ (1979). "The membrane attachment protein for spectrin is associated with band 3 in human erythrocyte membranes". Nature280 (5722): 468–73. doi:10.1038/280468a0. PMID379653.
^Singleton PA, Bourguignon LY (2004). "CD44 interaction with ankyrin and IP3 receptor in lipid rafts promotes hyaluronan-mediated Ca2+ signaling leading to nitric oxide production and endothelial cell adhesion and proliferation". Exp Cell Res295 (1): 102–18. doi:10.1016/j.yexcr.2003.12.025. PMID15051494.
^Kapfhamer D, Miller DE, Lambert S, Bennett V, Glover TW, Burmeister M (May 1995). "Chromosomal localization of the ankyrinG gene (ANK3/Ank3) to human 10q21 and mouse 10". Genomics27 (1): 189–91. doi:10.1006/geno.1995.1023. PMID7665168.