Espins (Espns) are actin-bundling proteins that are enriched in hair cell stereocilia and sensory cell microvilli. Espins bind actin monomer via their WH2 domain and can assemble actin bundles in cells []. They are multifunctional actin cytoskeletal regulatory proteins that act in various mechanosensory and chemosensory cells []. Mutations in the human Espn gene cause a profound form of congenital deafness [].