Involved in neuronal differentiation, including differentiation and migration of neuronal stem cells. Plays a role in neuronal plasticity and is involved in neurite and filopodia outgrowth, filopodia motility and probably synapse formation. GPM6A-induced filopodia formation involves mitogen-activated protein kinase (MAPK) and Src signaling pathways. May be involved in neuronal NGF-dependent Ca(2+) influx. May be involved in regulation of endocytosis and intracellular trafficking of G-protein-coupled receptors (GPCRs); may enhance internalization and recycling of mu-type opioid receptor (By similarity). Interacts with OPRM1 (By similarity). Interacts with palmitoyltransferase ZDHHC17/HIP14; the interaction leads to palmitoylation of GPM6A (By similarity). Localizes to cholesterol-rich lipid rafts of the plasma membrane of hippocampal neurons. Localized to plasma membrane of cell bodies and neurites of hippocampal neurons. Localized in membrane protrusions (filopodia and spines) of primary hippocampal neurons (By similarity). Localized to the growth cone edge membrane of elongating axons (By similarity). N-glycosylated. Palmitoylated by ZDHHC17/HIP14. Belongs to the myelin proteolipid protein family.