Protein Domain : Spectrin, beta subunit IPR016343

Type	Family
Description	Spectrins are involved in the support of general membrane integrity, stabilisation of cell-cell interactions, axonal growth, normal functioning of the Golgi complex and organisation of synaptic vesicles [ , , ]. Spectrin is a tetrameric actin cross-linking protein, which contains two alpha and two beta subunits. Two genes for alpha-spectrin [, , ] and five for beta-spectrin have been identified in both mice and humans, each of which is alternatively spliced to produce multiple spectrin isoforms [, ]. Beta-spectrins are more diverse than alpha-spectrin, and include mammalian erythrocytic beta-spectrin, non-erythroid beta-spectrin/Fodrin (beta-G, the general form of beta-spectrin expressed in multiple tissues), a novel beta-G spectrin (ELF1-4) that lacks the C-terminal PH (pleckstrin homology) domain, the brain-specific SPTBN2, and beta-V spectrin.ELF ( ), a modulator of the Smad adaptor proteins involved in the TGF-beta signalling pathway, was originally identified from endodermal stem/progenitor cells committed to foregut lineage [ , ]. ELF is a beta-spectrin that is important for distinct functional membrane generation, protein sorting, cell adhesion and the development of a polarized differentiated epithelial cell [, ]. ELF-deficient mice display disruption of transforming growth factor-beta (TGF-beta) signalling by Smad proteins []. Evidence from null mutants of ELF confirms that ELF is a novel beta-G spectrin and not an isoform of beta-spectrins []. Aberrations in Elf's involvement in Smad4 localization and subsequent activation of Smad4 could result in tumourigenesis.
Short Name	Spectrin_bsu