NGF promotes TrkA receptor endocytosis . The NGF/TrkA complex is endocytosed(49) mediated by clathrin or macropinocytosis by pincher to be internalization . Endosomes containing NGF/TrkA signals can undergo dynamic fusion processes and combine with other internalized products. NGF causes the development of complexes containing activated TrkA, clathrin heavy chains (CHC), and plasma membranes . Clathrin-coated vesicles (CCV) contain NGF, which binds to activated TrkA (p-TrkA) and other Ras-MAPK pathway activation components . NGF communicates via the incorporation of NGF, TrkA, and activation signal proteins. Retrograde transmission of occurs via axon transport in the early endosomes .