Tropomyosin receptor kinase A and p75 neurotrophin receptor complex (TrkA/p75NTR)

The TrkA/p75 complex is a high-affinity receptor system for Nerve Growth Factor (NGF), consisting of the receptor tyrosine kinase TrkA (encoded by NTRK1) and the p75 neurotrophin receptor (p75NTR, encoded by NGFR) [1.3.1, 1.5.1]. While TrkA and p75NTR can bind NGF independently with low affinity, their co-expression on the cell surface creates a high-affinity binding site that significantly enhances sensitivity to low concentrations of NGF, which is critical for the survival and differentiation of sensory and sympathetic neurons during development [1.3.1, 1.5.2]. Beyond its role in the nervous system, this receptor complex is a major driver in various cancers, particularly when NTRK1 undergoes genetic fusion, leading to constitutive kinase activation and uncontrolled cell proliferation [1.4.3, 1.4.5]. In the context of pain, the NGF-TrkA signaling axis is a primary mediator of nociception and peripheral sensitization, making it a key target for chronic pain therapies [1.1.5, 1.4.2]. Therapeutic strategies include small-molecule TRK inhibitors like larotrectinib and entrectinib for oncology, and monoclonal antibodies such as tanezumab that neutralize the NGF ligand to treat conditions like osteoarthritis [1.1.1, 1.4.5]. However, targeting this pathway presents challenges, including safety concerns like rapidly progressive osteoarthritis with NGF inhibitors and neurological side effects with pan-TRK inhibitors [1.1.1].

Other names

NTRK1/NGFR complexHigh-affinity nerve growth factor receptorTrkA-p75NTR complexp75NTR/TrkA complexNGF receptor complex

Inhibition of TrkA tyrosine kinase activity, neutralization of the Nerve Growth Factor (NGF) ligand, and modulation of neurotrophin receptor signaling pathways.