Functions in exocytosis in pancreatic acinar cells regulating the fusion of zymogen granules with each other. May have a pore-forming activity on membranes and regulate exocytosis in other exocrine tissues. Monomer and homooligomer; most probably hexameric. Interacts with GP2 (By similarity). Associated in a cholesterol-dependent manner with lipid rafts of zymogen granule membranes. Contains intrachain disulfide bonds. Mice display reduced rates of protein synthesis and intracellular transport of secretory proteins. According to PubMed:15040787 mice lacking Sycn display atrophy of the pancreas associated with an elevated amylase content.