Probable regulator of the Hippo/SWH (Sav/Wts/Hpo) signaling pathway, a signaling pathway that plays a pivotal role in tumor suppression by restricting proliferation and promoting apoptosis. Along with WWC1 can synergistically induce the phosphorylation of LATS1 and LATS2 and can probably function in the regulation of the Hippo/SWH (Sav/Wts/Hpo) signaling pathway. May act as a membrane stabilizing protein. May inhibit PI3 kinase by binding to AGAP2 and impairing its stimulating activity. Suppresses cell proliferation and tumorigenesis by inhibiting the CUL4A-RBX1-DDB1-VprBP/DCAF1 E3 ubiquitin-protein ligase complex (By similarity). Plays a role in lens development and is required for complete fiber cell terminal differentiation, maintenance of cell polarity and separation of the lens vesicle from the corneal epithelium. Interacts with SLC9A3R1, HGS and AGAP2. Interacts with SGSM3. Interacts (via FERM domain) with MPP1 (By similarity). Interacts with LAYN (PubMed:15913605). Interacts with WWC1. Interacts with the CUL4A-RBX1-DDB1-VprBP/DCAF1 E3 ubiquitin-protein ligase complex. The unphosphorylated form interacts (via FERM domain) with VPRBP/DCAF1. Interacts (via FERM domain) with NOP53; the interaction is direct (By similarity). Interacts with SCHIP1; the interaction is direct (By similarity). Colocalizes with MPP1 in non-myelin-forming Schwann cells. Binds with DCAF1 in the nucleus. The intramolecular association of the FERM domain with the C-terminal tail promotes nuclear accumulation. The unphosphorylated form accumulates predominantly in the nucleus while the phosphorylated form is largely confined to the non-nuclear fractions (By similarity). Additional isoforms seem to exist. Phosphorylation of Ser-518 inhibits nuclear localization by disrupting the intramolecular association of the FERM domain with the C-terminal tail. The dephosphorylation of Ser-518 favors the interaction with NOP53. Ubiquitinated by the CUL4A-RBX1-DDB1-DCAF1/VprBP E3 ubiquitin-protein ligase complex for ubiquitination and subsequent proteasome-dependent degradation. Mice are born with abnormally small lenses with serious structural defects. Failure of lens vesicle separation and the resulting changes in cell organization causes lenses to herniate, leading to expulsion of lens fiber cells through a perforation in the cornea. Developing lenses show loss of cell apical-basal polarity, failure of the lens vesicle to separate from the surface ectoderm, failure to properly exit the cell cycle during fiber cell differentiation and incomplete terminal differentiation of fiber cells.