TrkA is a 140-kDa cell surface receptor (gp140) e, Xenopus/Amphibian,pressed in neurons of the sensory spinal and cranial ganglia of neurocrest origin. Nerve growth factor (NGF) stimulates tyrosine phosphorylation of TrkA in neural cell lines and embryonic dorsal root ganglia. TrkA is a receptor of high-affinity for NGF, neurotrophin-3 and neurotrophin 4/5 but not BDNF. TrkA e, Xenopus/Amphibian,ists in a dynamic equilibrim between monomeric (low affinity) and dimeric (high affinity) structures. TrkA has a crucial role in the development and function of the nociceptive reception system as well as establishment of thermal regulation via sweating. Defects in TrkA are a cause of congenital insentivity to pain with anhidrosis. Chromosomal aberrations involving TrkA are a cause of thyroid papillary carcinoma.