Nerve growth factor is important for the development and maintenance of the sympathetic and sensory nervous systems (PubMed:20036257). Extracellular ligand for the NTRK1 and NGFR receptors, activates cellular signaling cascades to regulate neuronal proliferation, differentiation and survival (PubMed:22649032). The immature NGF precursor (proNGF) functions as ligand for the heterodimeric receptor formed by SORCS2 and NGFR, and activates cellular signaling cascades that lead to inactivation of RAC1 and/or RAC2, reorganization of the actin cytoskeleton and neuronal growth cone collapse (PubMed:22155786). In contrast to mature NGF, the precursor form (proNGF) promotes neuronal apoptosis (in vitro) (PubMed:20036257). Inhibits metalloproteinase-dependent proteolysis of platelet glycoprotein VI (By similarity). Binds lysophosphatidylinositol and lysophosphatidylserine between the two chains of the homodimer (PubMed:22649032, PubMed:26144237). The lipid-bound form promotes histamine relase from mast cells, contrary to the lipid-free form (PubMed:22649032). Homodimer (PubMed:1956407, PubMed:8201620, PubMed:20036257, PubMed:22649032, PubMed:26144237, PubMed:30061605). The homodimer interacts with a single NTRK1 chain (PubMed:22649032). The homodimer interacts with a single NGFR chain (By similarity). The NGF dimer interacts with a single SORCS2 chain (via extracellular domain) (PubMed:30061605). The NGF precursor (proNGF) binds to a receptor complex formed by SORT1 and NGFR, which leads to NGF endocytosis (PubMed:20036257). Both mature NGF and the immature NGF precursor (proNGF) interact with SORCS2 and with the heterodimer formed by SORCS2 and NGFR (via extracellular domains) (PubMed:22155786, PubMed:30061605). The NGF precursor (proNGF) has much higher affinity for SORCS2 than mature NGF (PubMed:24908487). The NGF precursor (proNGF) has much higher affinity for SORT1 than mature NGF (PubMed:20036257). Interacts with ADAM10 in a divalent cation-dependent manner (By similarity). ProNGF is endocytosed after binding to the cell surface receptor formed by SORT1 and NGFR. Detected in submaxillary gland (at protein level) (PubMed:1284621). Highly expressed in male submaxillary gland. Levels are much lower in female submaxillary gland (PubMed:6336309, PubMed:1284621). Expression oscillates in a circadian manner in the suprachiasmatic nucleus (SCN) of the brain. Belongs to the NGF-beta family.