Nerve growth factor

Abstract NGF is the first member of the neurotrophin-family trophic factors. NGF regulates the growth, maintenance, proliferation, and survival of certain target neurons through activation of the high affinity receptor, tropomyosin receptor kinase A (TrkA). NGF is also involved in apoptosis through binding to the low affinity receptor, p75NTR. NGF consists of three subunits, a, b, and g, which specifically interact to form a 7S, 130-kDa complex. The complex contains two identical 120 amino acid β-subunits, which are solely responsible for nerve growth stimulating activity. Therefore, in much of the literature, including this chapter, the term NGF refers to the “β-subunit” in mature form.