Acts as an inhibitor of the small GTPase RHOA and plays several roles in the regulation of myoblast and hair cell differentiation, lymphocyte T proliferation and neutrophil polarization (PubMed:25588844, PubMed:27269051). Plays a role in fetal mononuclear myoblast differentiation by promoting filopodia and myotube formation (PubMed:17150207). Maintains naive T lymphocytes in a quiescent state and prevents chemokine-induced T lymphocyte responses, such as cell adhesion, polarization and migration (By similarity). Involved also in the regulation of neutrophil polarization, chemotaxis and adhesion (PubMed:25588844). Required for normal development of inner and outer hair cell stereocilia within the cochlea of the inner ear (PubMed:27269051). Plays a role for maintaining the structural organization of the basal domain of stereocilia (PubMed:27269051). Involved in mechanosensory hair cell function (PubMed:27269051). Required for normal hearing (PubMed:27269051). Homooligomer; homooligomerization is regulated by RHOC and leads to the formation of concatemers through the association of N- and C-termini (PubMed:27269051). Interacts (phosphorylated form) with 14-3-3 proteins; these interactions occur during myogenic cell differentiation and also induces T cell proliferation arrest (By similarity). Interacts (phosphorylated form) with HDAC6; this interaction occurs during early myogenic differentiation, prevents HDAC6 to deacetylate tubulin and also induces T cell proliferation arrest (By similarity). Interacts with DYSF; this interaction occurs during early myogenic differentiation (PubMed:24687993). Interacts with MYOF (By similarity). Interacts (via active GTP- or inactive GDP-bound forms) with RHOA; this interaction is direct, blocks the loading of GTP to RHOA and decreases upon chemokine CCL19 stimulation in primary T lymphocytes (PubMed:27269051). Interacts with RHOC (PubMed:27269051). Interacts (via phosphorylated form) with YWHAB; this interaction occurs in a chemokine-dependent manner and does not compete for binding of RIPOR2 with RHOA nor blocks inhibition of RIPOR2-mediated RHOA activity (By similarity). Interacts with YWHAE (By similarity). Interacts with YWHAQ (By similarity). Localized in the cytoplasm in cells undergoing mitosis (By similarity). Colocalized with F-actin (By similarity). Accumulates at the leading edge of polarized neutrophils in a chemokine-dependent manner (By similarity). Localized with RHOC within the basal domain of hair cell stereocilia, near the taper region (PubMed:27269051). Detected in punctate pattern forming a circumferential ring at the stereocilia base (PubMed:27269051). Localized to the apical stereocilia of inner and outer hair cells (By similarity). Not detected as a membrane-associated protein in stereocilia (PubMed:27269051). Expressed in the cochlea (PubMed:24958875). Expressed in inner hair cells and outer hair cells and Hensen's cells (at protein level) (PubMed:27269051). Expressed in the brain, cerebellum, spinal cord, retina, heart, spleen liver, kidney, bladder, muscle and lung (PubMed:24958875, PubMed:27269051). Expressed in the cochlea of the inner ear (PubMed:24958875, PubMed:27269051). Up-regulated during regenerating muscle tissue. Phosphorylated. Chemokine-induced phosphorylation in neutrophils occurs in a PKC- and AKT-dependent manner, resulting in RIPOR2 interaction with YWHAB and stabilization. Phosphorylated by PKCA, AKT1 and MAPKAPK1A; in vitro. Mice are deaf at 4 weeks of age (PubMed:27269051). Show abnormal hair bundle morphology and polarity and stereociliary growth in the cochlea of the inner ear (PubMed:27269051). Display mislocalization of protein TPRN to the base of stereocilia (PubMed:27269051). Show reduced mechanotransduction currents in hair bundles of outer hair cells (PubMed:27269051). Mice show impaired neutrophil chemotaxis, increased neutrophil adhesion to endothelial cell and reduced neutrophil infiltration into inflamed peritonea (PubMed:25588844). Display increased chemokine-induced RHOA activity and mislocalization of myosin light chain MYL2 in neutrophils (PubMed:25588844). Belongs to the RIPOR family.