Up-regulates the activity of the Rho guanine nucleotide exchange factor ARHGEF18 (PubMed:22006950). Involved in the regulation of the circumferential actomyosin belt in epithelial cells (PubMed:22006950). Promotes cellular adhesion, migration and motility in vitro and may play a role in wound healing (By similarity). May have a role in mediating cytoskeletal changes associated with steroid-induced cell differentiation (By similarity). Interacts (via FERM domain) with ARHGEF18 (via C-terminus); the interaction activates ARHGEF18. Accumulates along apical cell-cell boundaries and is also detected in the cytoplasm in a punctate manner. Expressed in mouse liver cells, with lower amounts in lung, kidney and in 7- to 17-day embryos. Expression not detected in adult mouse heart, brain, spleen, skeletal muscle or testis. May be negatively regulated by phosphorylation.