Erythrocyte Membrane Protein Band 4.9 (EPB49)

Dematin, or EPB49, is an actin-bundling protein originally identified in the erythroid membrane skeleton. Its actin-bundling activity is abolished upon phosphorylation by cAMP-dependent protein kinase and is restored after dephosphorylation.

The deduced 383-amino acid protein has a calculated molecular mass of 43 kD. Dematin has a polyglutamine motif that may constitute a nuclear localization signal, a PEST sequence, a C-terminal domain highly similar to the C-terminal headpiece domain of villin (VIL), and several putative phosphorylation sites. Northern blot analysis detected variable dematin expression in all tissues examined. Immunofluorescence microscopy revealed punctate dematin staining around the cell nucleus in cultured human erythroblasts.