Roles of glial p75NTR in axonal regeneration
The neurotrophin receptor p75 (p75NTR) is expressed by both neurons and glia. Nerve injury triggers up-regulation of p75NTR in Schwann cells (SC) but not in central glia. In contrast to neuronal p75NTR, which mediates negative signals from myelin-associated proteins resulting in neurite collapse, glial p75NTR may play a positive role in nerve regeneration by forming neurotrophin chemoattractant gradients or by competitively antagonizing the NOGO/NgR/LINGO-1 signal through cell-cell contact or regulated intramembranous proteolysis (RIP) of p75NTR. This piece presents some recent evidence supporting this hypothesis. © 2007 Wiley-Liss, Inc.