TrkB is part of a sub-family of protein kinases which includes also TrkA and TrkC. There are other neurotrophic factors structurally related to BDNF: NGF (for Nerve Growth Factor), NT-3 (for Neurotrophin-3) and NT-4 (for Neurotrophin-4).
TrkB is a member of the protein kinase sub-family that encompasses TrkA and TrkC. Neurotrophic factors, such as BDNF, have structurally related counterparts: NGF (Nerve Growth Factor), NT-3 (Neurotrophin-3) and NT-4 (Neurotrophin-4).