The heterodimer formed by NGFR and SORCS2 functions as receptor for the precursor forms of NGF (proNGF) and BDNF (proBDNF). ProNGF and proBDNF binding both promote axon growth cone collapse (in vitro). Plays a role in the regulation of dendritic spine density in hippocampus neurons. Required for normal neurite branching and extension in response to BDNF. Plays a role in BDNF-dependent hippocampal synaptic plasticity. Together with NGFR and NTRK2, is required both for BDNF-mediated synaptic long-term depression and long-term potentiation. ProNGF binding promotes dissociation of TRIO from the heterodimer, which leads to inactivation of RAC1 and/or RAC2 and subsequent reorganization of the actin cytoskeleton. Together with the retromer complex subunit VPS35, required for normal expression of GRIN2A at synapses and dendritic cell membranes. Required for normal expression of the amino acid transporter SLC1A1 at the cell membrane, and thereby contributes to protect cells against oxidative stress.; [SorCS2 122 kDa chain]: Does not promote Schwann cell apoptosis in response to proBDNF.; SorCS2 104 kDa chain and SorCS2 18 kDa chain together promote Schwann cell apoptosis in response to proBDNF.