May regulate secretion and presynaptic differentiation through inhibition of the activity of N-type voltage-gated calcium channel (PubMed:12783849). May activate the MAP kinase JNK (PubMed:15123616). Plays a role in neurite outgrowth (By similarity). During dendritic spine formation can bidirectionally induce pre- and post-synaptic differentiation of neurons by trans-synaptically binding to PTPRD (By similarity).