Probably involved in connections of major cytoskeletal structures to the plasma membrane. In epithelial cells, required for the formation of microvilli and membrane ruffles on the apical pole. Along with PLEKHG6, required for normal macropinocytosis (By similarity). A head-to-tail association, of the N-terminal and C-terminal halves results in a closed conformation (inactive form) which is incapable of actin or membrane-binding. Interacts with PALS1 and SLC9A3R2. Found in a complex with EZR, PODXL and SLC9A3R2 (By similarity). Interacts with MCC, PLEKHG6, PODXL, SCYL3/PACE1, SLC9A3R1 and TMEM8B. Interacts (when phosphorylated) with FES/FPS. Interacts with dimeric S100P, the interaction may be activating through unmasking of F-actin binding sites (By similarity). Identified in complexes that contain VIM, EZR, AHNAK, BFSP1, BFSP2, ANK2, PLEC, PRX and spectrin (PubMed:21745462). Detected in a complex composed of at least EZR, AHNAK, PPL and PRX (By similarity). Interacts with PDPN (via cytoplasmic domain); activates RHOA and promotes epithelial-mesenchymal transition (By similarity). Interacts with SPN/CD43 cytoplasmic tail (PubMed:9472040, PubMed:21289089). Interacts with CD44 and ICAM2 (PubMed:9472040). Localization to the apical membrane of parietal cells depends on the interaction with PALS1. Microvillar peripheral membrane protein (cytoplasmic side). Localizes to cell extensions and peripheral processes of astrocytes (By similarity). Detected in eye lens fiber cells (PubMed:21745462). Expressed in cerebrum and cerebellum (at protein level) (PubMed:15797715). Component of the microvilli of intestinal epithelial cells. Detected in whole embryo from 5 dpc with highest expression at 8, 11, 12, and 18 dpc. Expressed at 18 dpc in brain, a clear reduction occurs after birth followed by a transient increase around 2 weeks to 1 month. Hardly detected in adult brain. Has three main structural domains: an N-terminal FERM domain, a central alpha-helical domain and a C-terminal actin-binding domain. The FERM domain is organized in a clover-shaped structure that comprises three subdomains identified as F1 (residues 2-82), F2 (residues 96-198), and F3 (residues 204-296). In the active form, the subdomain F3 adopts two mutually exclusive conformational isomers where a row of four phenylalanine side chains (Phe250, Phe255, Phe267 and Phe269) must point in the same direction. In the autoinhibited form, the F3 subdomain interacts with the C-terminal domain (residues 516-586) and stabilizes the structure, selecting only one possible arrangement of phenylalanine side chains. The FERM domain mediates binding to membrane lipids and signaling molecules. The central alpha-helical domain is composed of two alpha helices (residues 326-406 and 417-466) connected by a linker. It protrudes from the FERM domain forming a coiled coil structure where the linker can have either a loop or a helix conformation. The monomer is predicted to form an intra-molecular helix-loop-helix coiled coil structure. Whereas the dimer adopts an elongated dumbbell-shaped configuration where continuous alpha helices from each protomer are organized in a antiparallel coiled coil structure that connect FERM:C-terminal domain swapped complex at each end. The dimer is predicted to link actin filaments parallel to the plasma membrane. The [IL]-x-C-x-x-[DE] motif is a proposed target motif for cysteine S-nitrosylation mediated by the iNOS-S100A8/A9 transnitrosylase complex. Phosphorylated by tyrosine-protein kinases. Phosphorylation by ROCK2 suppresses the head-to-tail association of the N-terminal and C-terminal halves resulting in an opened conformation which is capable of actin and membrane-binding. S-nitrosylation is induced by interferon-gamma and oxidatively-modified low-densitity lipoprotein (LDL(ox)) possibly implicating the iNOS-S100A8/9 transnitrosylase complex.