Figure 1.

Different sites of potential interactions between sortilin and pro-neurotrophins. The pro-neurotrophin (pro-NT) binding site in sortilin is exposed after proteolytic cleavage of the sortilin propeptide in the Golgi apparatus, raising the possibility of an intra-Golgi interaction. The molecules would then travel together to the plasma membrane, where they might form an autoactivating complex for p75 on the same cell; alternatively, a second cleavage event might release a soluble complex to the extracellular milieu.