A recurring theme in neurobiology is the role of a set of molecules that support proliferation, differentiation and survival of neurons. These molecules, collectively referred to as neurotrophins, are essential for the development and maintenance of the vertebrate nervous system, mediating their signal into the cell by specific interaction with tyrosine kinase receptors of the TRK (Tyrosine Kinase Receptor) family. TRK family is composed of related transmembrane tyrosine receptor kinases that specifically bind neurotrophins: TRKA binds NGF (Nerve Growth Factor); TRKB binds BDNF (Brain Derived Neurotrophic Factor), NT3 (Neurotrophin-3) and NT4/5 (Neurotrophin-4/5); and TRKC binds NT3. Out of these, TRKA forms a high-affinity binding site for NGF, the best characterized member of the neurotrophin family, which is involved in a [...]