Secreted glycoprotein regulating the activation of different signaling pathways in adjacent cells to control different processes including cell adhesion, cell-matrix adhesion, cytoskeleton organization and cell migration. Promotes substrate adhesion, spreading and formation of focal contacts. Negatively regulates cell-matrix adhesion and stress fiber assembly through Rho protein signal transduction. Modulates the organization of actin cytoskeleton by stimulating the formation of stress fibers through interactions with components of Wnt signaling pathways. Promotes cell migration through activation of PTK2 and the downstream phosphatidylinositol 3-kinase signaling. Plays a role in bone formation and promotes osteoblast differentiation in a dose-dependent manner through mitogen-activated protein kinase signaling. Mediates myelination in the peripheral nervous system through ERBB2/ERBB3 signaling. Plays a role as a regulator of muscle hypertrophy through the components of dystrophin-associated protein complex. Involved in positive regulation of mitochondrial depolarization. Plays a role in neurite outgrowth. May participate in the obstruction of fluid outflow in the trabecular meshwork. Homodimer (via N-terminus). Can also form higher oligomers. Interacts with OLFM3, FN1, NRCAM, GLDN and NFASC. Interacts (via N-terminus) with MYL2. Interacts with SFRP1, FRZB, FZD7, FZD10, FZD1 and WIF1; regulates Wnt signaling (By similarity). Interacts with SNTA1; regulates muscle hypertrophy. Interacts with ERBB2 and ERBB3; activates ERBB2-ERBB3 signaling pathway. Interacts with SNCG; affects its secretion and its aggregation (By similarity). Located preferentially in the ciliary rootlet and basal body of the connecting cilium of photoreceptor cells, and in the rough endoplasmic reticulum. It is only imported to mitochondria in the trabecular meshwork. Localizes to the Golgi apparatus in Schlemm's canal endothelial cells. Appears in the extracellular space of trabecular meshwork cells by an unconventional mechanism, likely associated with exosome-like vesicles. Localizes in trabecular meshwork extracellular matrix. Remains retained in the endoplasmic reticulum. Expressed in optic nerve head, ciliary body and retina. Palmitoylated. Undergoes a calcium-dependent proteolytic cleavage at Arg-212 by CAPN2 in the endoplasmic reticulum. The result is the production of two fragments, one of 35 kDa containing the C-terminal olfactomedin-like domain, and another of 20 kDa containing the N-terminal leucine zipper-like domain (By similarity). Glycosylated.