Function
Spectrin forms scaffolding in plasma membranes and cytoskeletal structure. It interacts with actin at either end of its tetramer[1]. The SPT dimer is formed by association of α1 and β1 monomers. In invertebrates there are SPT α, β and βH. In vertebrates there are SPT α1 (SPTA1), α2 (SPTA2) and β1 (SPTB1) to β5. SPT contains an SRC Homology 3 domain (SH3), a Pleckstrin Homology (PH) domain and a Calponin Homology (CH) domain.
- Spectrin α2 is expressed highly in heart muscle cells[2].
- Spectrin β2 is associated with GABA receptor at dendritic synapses[3].
- Spectrin β4 is associated with GABA receptor at axon initial segment synapses.
Disease
Mutations in SPT α are found in patients with hereditary elliptocytosis[4]. SPT β deficiency is found in hereditary spherocytosis[5].
3D Structures of Spectrin
Spectrin 3D structures