THE SIGNIFICANCE OF LAMELLATED STRUCTURE OF GOLGI-APPARATUS IN PAROTID ACINAR-CELLS

By reviewing briefly our recent study, the functional significance of lamellated structure of the Golgi apparatus (GA) was discussed. We hav e examined the structural alterations and distribution of Golgi relate d proteins in GA disorganized by brefeldin A (BFA), okadaic acid (OA), monensin and nocodazole (NOC) by means of electron microscopy. BFA an d OA induced rapid disruption of lamellated structure of GA into group s of small vesicles and tubules. The effect of these drugs was reversi ble, and lamellated structure recovered immediately after withdrawal o f the drugs. Immunoelectron microscopy revealed that the localization of amylase, GF-1 antigen (a resident protein of trans membrane of GA) and cathepsin D was modified considerably in the cells whose lamellate d structures were in the middle of disorganization or reconstruction. These modifications include appearance of cathepsin D and GF-1 immunor eactivity in the secretory granules. Furthermore, there was evidence t hat secretory products were discharged not only into the acinar lumen but also into the baso-lateral spaces. In contrast, the stacked config uration was preserved in GA after treatment with monensin or NOC. Loca lization of immunoreactivity of the Golgi related proteins was essenti ally not changed by these drugs. These findings suggested that the cis ternal stack of GA was the structural background for the normal sortin g of secretory proteins.