Neurotrophic factors, as the name suggests, support the growth, survival and maintenance of neurons. They are a varied group of proteins that play important roles in nervous system development and, later, homeostasis. Some neurotrophic factors may also function in regulating neuronal activity, and possibly contribute to regeneration of damaged neurons after injury.
Within this group, the Neurotrophins are a small family of secreted proteins that regulate neuron survival, development and function. They are synthesized as pre-propeptides that are proteolytically cleaved, giving rise to active propeptides and mature homodimers. The mature forms of most neurotrophins show high homology between species. Neurotrophins signal through two receptor types, the Trk family of receptor tyrosine kinases and p75NTR, a TNF receptor superfamily member.
Proteins categorized as Neurotrophic Factors belong to the GDNF, Neurotrophin/Trk and VPS10P-domain families, plus other non-grouped neurotrophic factors and receptors like CNTF.