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. Conflictingly, PubMed:22162747 reports that induced cellular protrusions are simple membrane-wrapped tubules without actin or tubulin-based cytoskeletons and with Gpm6a gliding along membrane edges indicative for a function in actin-independent membrane deformation. 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); enhances internalization and recycling of mu-type opioid receptor. 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 (PubMed:21714103). Widely expressed in the CNS. Found especially in the granule cell layer of the cerebellum but not in the molecular layer or white matter. Expressed in the immature embryonic retina including the nerve fiber layer (NFL), inner plexiform layer (IPL), and outer plexiform layer (OPL). Weakly expressed in processes of Mueller glia cells. First detected in presumptive postmitotic neurons in the developing neural tube at embryonic day 9. Expressed in 14 dpc retinas, and expression continued after birth with a slight decrease between P12 and P15. In the 14 dpc retina is mainly and strongly expressed in the NFL. In P1 and P5 retinas strong expression is confined to the IPL and also in NFL. At P10 and in the adult retina strong expression is detected in the IPL, and weak expression in NFL, OPL, and inner nuclear layer. Is expressed on postmitotic mature neurons. N-glycosylated. Palmitoylated by ZDHHC17/HIP14. Belongs to the myelin proteolipid protein family.