Spectrin is a cytoskeletal protein that lines the intracellular side of the plasma membrane of many cell types in pentagonal or hexagonal arrangements, forming scaffolds and playing an important role in maintenance of plasma- membrane integrity and cytoskeletal structure. The hexagonal arrangements are formed by tetramers of spectrin associating with short actin filaments at either end of the tetramer. These short actin filaments act as junctional complexes, allowing the formation of the hexagonal mesh.

Spectrin is found in the intracellular side of the plasma membrane of many cell types found in muscles, red blood cells and red cell precursors. Anti-Spectrin antibody is useful in the diagnosis of Erythroid Leukemias and it may be a superior marker to  Glycophorin for the identification of erythroid precursors.