Nogo Receptor (NgR)

Nogo receptor (NgR) is a glycosylphosphatidylinositol (GPI)-anchored membrane protein encoded by the RTN4R gene, which exhibits high affinity for a region of Nogo. The NgR receptor mediates the inhibition of axonal growth and is predominantly expressed in neurons and axons of the central nervous system (CNS).
NgR family comprises three members: NgR1, NgR2, and NgR3. NgR1 mediates the inhibitory effects of myelin-associated inhibitors (MAIs) such as Nogo-A, MAG, and OMgp on axonal regeneration (although there is some controversy among studies). NgR2 serves as a receptor for MAG, binding to it but not to Nogo. In contrast, NgR3 does not interact with any MAIs. Additionally, NgR1 and NgR3 have been identified as receptors for chondroitin sulfate proteoglycans (CSPGs).
NgR itself lacks an intracellular domain and relies on transmembrane coreceptors (such as p75NTR) to transmit inhibitory signals. NgR is involved in neuronal regeneration and repair, as well as the remodeling of brain structure and function. It is a critical component in the regulation of axonal growth and regeneration in the CNS, holding significant implications for therapeutic strategies aimed at promoting recovery after neural injuries^[1][2][3][4].