TrkA

TrkA (tropomyosin receptor kinase A; encoded by NTRK1) is a high-affinity receptor tyrosine kinase for nerve growth factor (NGF) that regulates neuronal survival, differentiation, and sensory neuron function through ligand-induced receptor dimerization and autophosphorylation^[1][2]. Mechanistically, NGF-TrkA signaling activates major downstream pathways including RAS/MAPK, PI3K/AKT, and PLCγ, thereby controlling transcriptional programs that support neuronal growth, maintenance, and synaptic function^[1][2][3]. Through these signaling cascades, TrkA plays a central role in the development and maintenance of nociceptive neurons and contributes to neurotrophin-dependent cellular responses in the peripheral and central nervous systems^[1][2]. In disease contexts, dysregulation of NGF/TrkA signaling has been implicated in chronic pain disorders and neurodegenerative conditions, including experimental models of Alzheimer's disease in which impaired TrkA signaling is associated with cholinergic neuronal dysfunction and synaptic deficits^[3][4][5]. Compared with related neurotrophin receptors, TrkA is distinguished by its preferential activation by NGF, whereas TrkB primarily responds to BDNF and NT-4/5 and TrkC is activated predominantly by NT-3, enabling receptor-specific biological outcomes^[6]. For experimental applications, both agonists and antagonists targeting the NGF-TrkA axis have been widely utilized to investigate neurotrophic signaling, neuronal survival mechanisms, and pain-related pathways, making TrkA an important molecular target in translational neuroscience research^[4][5].