Functional component of the Nogo receptor signaling complex (RTN4R/NGFR) in RhoA activation responsible for some inhibition of axonal regeneration by myelin-associated factors. Is also an important negative regulator of oligodentrocyte differentiation and axonal myelination (By similarity). Homotetramer. Forms ternary complex with RTN4R/NGFR and RTN4R/TNFRSF19 (By similarity). Expressed broadly in the spinal cord, including the ventral portion of the ventricular zone, and motor neurons. Expressed also in the dorsal root ganglion and boundary cap cells at dorsal and ventral roots. In the early embryonic brain, is first expressed in the prosencephalon and the ventral mesencephalon, and later in the telencephalon, the rostral part of the mesencephalon and some parts of the hindbrain. Expressed also in the ventral part of the neural retina and trigeminal and facial nerves. N-glycosylated. Contains predominantly high-mannose glycans (By similarity).