Neurotrophins and their receptors: signaling trios in complex biological systems

Abstract

The neurotrophins, a class of four related growth factors, utilize a dual receptor system consisting of Trk receptor tyrosine kinases and the structurally unrelated p75^NTR to modulate diverse and sometimes opposing biological actions. The identification of novel ligands for p75^NTR, unconventional mechanisms for Trk activation and unique signaling intermediates further underscores the complex nature of neurotrophin: receptor interactions, as well as their functions within and outside of the nervous systems. This review summarizes recent surprises of how ligand-receptor pairing may affect diverse developmental events, regulate response to injury and extend their influence on memory and learning.