Cytoskeletal Components Related to the Transport of Fuzzy Coated Vesicles and Secretory Granules in Acinar Cells of the Rat Submandibular Gland by Quick-frozen Freeze-substitution Fixation Method

Abstract

Cytoskeletal components concerned with the intracellular transport of the fuzzy coated vesicles from the Golgi apparatus to the immature secretory granules, and the secretory granules toward the plasma membrane in the acinar cells of the rat submandibular gland were investigated using the quick-frozen freeze-substitution fixation method. It was observed that actin-like filamentous structures (4.2nm) connected fuzzy coated vesicles with intermediate filaments (9.2nm) in the vicinity of the Golgi area. It was also demonstrated that mature secretory granules were connected to the microtubules by actin-like filamentous structures and rod-like structures.The rod-like structure was composed of two globular structures and a filamentous structure. These observations suggest that actin-like filamentous structures, intermediate filaments, rod-like structures and microtubules were involved in the transport of fuzzy coated vesicles and secretory granules.