UNC119B is a myristoyl-binding protein that acts as a cargo adapter: specifically binds the myristoyl moiety of a subset of N-terminally myristoylated proteins and is required for their localization. It binds myristoylated NPHP3 and plays a key role in localization of NPHP3 to the primary cilium membrane. UNC119B does not bind all myristoylated proteins and probably plays a role in trafficking proteins in photoreceptor cells.