FERM (Four.1 protein, Ezrin, Radixin, Moesin) domain, F1 sub-domain, found in moesin and similar proteins
Moesin, also termed membrane-organizing extension spike protein, is a member of the ezrin/radixin/moesin (ERM) family of cytoskeletal proteins that plays an essential role in microvilli formation, T-cell activation, and tumor metastasis through providing a regulated linkage between F-actin and membrane-associated proteins. These proteins may also function in signaling cascades that regulate the assembly of actin stress fibers. The ERM proteins consist of an N-terminal FERM domain, a coiled-coil (CC) domain and a C-terminal tail segment (C-tail) containing a well-defined actin-binding motif. The C-terminal domain can fold back to bind to the FERM domain forming an autoinhibited conformation. The FERM domain is made up of three sub-domains, F1, F2, and F3. This family corresponds to F1 sub-domain, which is also called the N-terminal ubiquitin-like structural domain of the FERM domain (FERM_N). Moesin is involved in mitotic spindle function through stabilizing cell shape and microtubules at the cell cortex. It is required for the formation of F-actin networks that mediate endosome biogenesis or maturation and transport through the degradative pathway.