Three-dimensional Dynamics of the Golgi Apparatus of Parotid Acinar Cells as Analyzed by Computer Graphics of Cytochemically-marked Serial Sections.

We examined the effects of specific inhibitors, brefeldin A (BFA) and okadaic acid (OA), on the ultrastructural organization of the Golgi apparatus and distributions of amylase, Golgi-associated proteins, and cathepsin D in the rat parotid acinar cells. BFA induced a rapid regression of the Golgi stack into rudimentary Golgi clusters composed of tubulovesicules, in parallel with a redistribution of the Golgi-resident proteins and a coat protein (β-COP) into the region of the rough endoplasmic reticulum (rER) or cytosol. The rapid disruption of the Golgi stack could also be induced by the effect of OA. However, redistribution of the Golgi proteins in rER or cytosol could not be observed and β-COP was not dispersed but was retained on the rudimentary Golgi apparatus. These findings suggested that the mechanism of OA in inducing degeneration of the Golgi stack was markedly different from that of BFA. In addition, missorting of amylase, a Golgi protein, and cathepsin D into incorrect transport pathways is apparent in the course of the disruption of the Golgi stack by OA. These Golgi-disrupting effects are reversible and the reconstruction of the stacked structure of the Golgi apparatus started immediately after the removal of inhibitors. In the recovery processes, missorting was also observed until the integrated structure of the Golgi apparatus was completely reconstructed. This suggested that the integrated structure of the Golgi apparatus was quite necessary for the occurrence of normal secretory events, including proper sorting of molecules.

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Buds of the Golgi Apparatus in Parotid Acinar Cells

European Journal of Morphology ◽

10.1076/ejom.40.4.247.16697 ◽

2002 ◽

Vol 40 (4) ◽

pp. 247-251

Author(s):

Hideaki Tamaki ◽

Akihisa Segawa ◽

Shohei Yamashina

Keyword(s):

Golgi Apparatus ◽

Acinar Cells ◽

Parotid Acinar Cells

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Effects of secretory stimulation on the Golgi apparatus and GERL of rat parotid acinar cells.

Journal of Histochemistry & Cytochemistry ◽

10.1177/32.4.6142913 ◽

1984 ◽

Vol 32 (4) ◽

pp. 403-412 ◽

Cited By ~ 26

Author(s):

A R Hand ◽

C Oliver

Keyword(s):

Golgi Apparatus ◽

Functional Relationship ◽

Secretory Granules ◽

Acinar Cells ◽

Dynamic Nature ◽

Parotid Acinar Cells ◽

Golgi Region ◽

Thiamine Pyrophosphatase ◽

Rat Parotid

The structure and cytochemistry of the Golgi apparatus and GERL of rat parotid acinar cells was studied after in vivo secretory stimulation with isoproterenol. Discharge of mature secretory granules was complete within 1 hr after isoproterenol injection, but immature granules in the Golgi region or near the lumen were not released. At early times (1-5 hr) after isoproterenol, acid phosphatase (AcPase) activity was markedly increased in GERL and immature secretory granules compared to uninjected controls. GERL appeared increased in extent and numerous continuities with immature granules were observed. Reaccumulation of mature secretory granules was first evident at 5 hr, and was almost complete by 16 hr after isoproterenol. Thiamine pyrophosphatase (TPPase) activity, normally restricted to the trans Golgi saccules, was frequently present in immature granules during this time. Narrow cisternae resembling GERL, occasionally in continuity with immature granules, also contained TPPase reaction product. By 16-24 hr after stimulation, the activity and distribution of AcPase and TPPase were similar to control cells. These results demonstrate the dynamic nature of the Golgi apparatus and GERL in parotid acinar cells, and emphasize the close structural and functional relationship between these two structures.

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