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. 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. Identified in complexes that contain VIM, EZR, AHNAK, BFSP1, BFSP2, ANK2, PLEC, PRX and spectrin. Detected in a complex composed of at least EZR, AHNAK, PPL and PRX. Interacts with PDPN (via cytoplasmic domain); activates RHOA and promotes epithelial-mesenchymal transition. Interacts with SPN/CD43 cytoplasmic tail, CD44 and ICAM2 (By similarity). 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). 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 (By similarity). S-nitrosylation is induced by interferon-gamma and oxidatively-modified low-densitity lipoprotein (LDL(ox)) possibly implicating the iNOS-S100A8/9 transnitrosylase complex.