Extracellular matrix serine protease secreted by pioneer neurons that plays a role in layering of neurons in the cerebral cortex and cerebellum by coordinating cell positioning during neurodevelopment. Regulates microtubule function in neurons and neuronal migration. Binding to the extracellular domains of lipoprotein receptors VLDLR and LRP8/APOER2 induces tyrosine phosphorylation of DAB1 and modulation of TAU phosphorylation. Affects migration of sympathetic preganglionic neurons in the spinal cord, where it seems to act as a barrier to neuronal migration. Enzymatic activity is important for the modulation of cell adhesion. . This is the function of RELN (reelin, ENSG00000189056).