Fig. 1

Activation of the high-affinity receptor TrkA and the low-affinity receptor NGFR by NGF. Left, TrkA activation by NGF leads to dimerization of the receptor and phosphorylation of different tyrosine residues in the intracellular domain, which in turn promote the formation of binding sites for signaling effectors. Right, NGFR binds NGF through the cysteine-rich repeats endowed within its extracellular domain. Middle, when TrkA and NGFR are co-expressed, NGFR might enhance the binding affinity of TrkA for NGF, either by increasing the NGF concentration at cell surface or modifying the Trk A conformation through allosteric interactions [47]