May play a role in regulated exocytosis (PubMed:10383386). Modulates the localization of synaptophysin/SYP into synaptic-like microvesicles and may therefore play a role in synaptic-like microvesicle formation and/or maturation (PubMed:15590695, PubMed:12928441). Involved in the regulation of short-term and long-term synaptic plasticity (By similarity). Nervous system (at protein level). Belongs to the synaptogyrin family.