RTN4 and nervous system disorder: Once Nogo-A activates the NgR1 complex, RhoA-GTP is phosphorylated to ROCK2, which in turn can phosphorylate the collapsin response mediator protein 2 (CRMP2) at the threonine 555 amino acid site; demonstrated to promote axonal retraction and potentiate axonal sprouting observed in neurological disease models [20].