Pathways & interactions
Pleckstrin homology domain, spectrin-type (IPR001605)
Short name: PH_dom-spectrin-type
Overlapping homologous superfamilies
- PH-like domain superfamily (IPR011993)
- Pleckstrin homology domain (IPR001849)
- Pleckstrin homology domain, spectrin-type (IPR001605)
Spectrin is the major constituent of the cytoskeletal network underlying the erythrocyte plasma membrane; it associates with band 4.1 and actin to form the cytoskeletal super-structure. The native spectrin molecule is a tetramer comprising two anti-parallel heterodimers joined head to head, such that the C terminus of the alpha-subunit and the N terminus of the beta-subunit are included within the same molecule.
Spectrin is similar to alpha-actinin and dystrophin, and contains a pleckstrin homology (PH) domain. The exact function of the PH domain is unknown, but evidence suggests that it contains an electrostatically-polarised pocket that facilitates binding of a ligand (e.g., a peptide). The PH domain contains a number of hydrophobic residues that form a hydrophobic core responsible for protein stability. The spectrin PH domain [PMID: 8208297], which has the familiar 7-stranded anti-parallel up and down beta-barrel capped by a C-terminal amphiphilic alpha helical cap [PMID: 8208296], contains insertions that confer 2 additional turns of alpha-helix in the loop between strands 3 and 4. The C-terminal helix is packed into a gorge between strands 1 and 2, and lies parallel to strand 7 [PMID: 8599766].
- PR00683 (SPECTRINPH)