The small GTPase Rab33A participates in regulation of amylase release from parotid acinar cells

Amylase is released from exocrine parotid acinar cells via typical exocytosis. Exocytosis of amylase-containing granules occurs through several steps, including formation, maturation, and transport of granules. These steps are thought to be regulated by members of the small GTPase Rab family. We pre...

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Bibliographic Details
Published in:Biochemical and biophysical research communications 2015-06, Vol.461 (3), p.469-474
Main Authors: Imai, Akane, Tsujimura, Maiko, Yoshie, Sumio, Fukuda, Mitsunori
Format: Article
Language:English
Subjects:
Amylase release
Amylases - metabolism
Animals
Base Sequence
DNA Primers
Intracellular distribution
Male
Parotid
Parotid Gland - cytology
Parotid Gland - enzymology
Polymerase Chain Reaction
rab GTP-Binding Proteins - physiology
Rab33A
Rats
Rats, Wistar
β-stimulation
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Summary:Amylase is released from exocrine parotid acinar cells via typical exocytosis. Exocytosis of amylase-containing granules occurs through several steps, including formation, maturation, and transport of granules. These steps are thought to be regulated by members of the small GTPase Rab family. We previously demonstrated that Rab27 and its effectors mediate amylase release from parotid acinar cells, but the functional involvement of other Rab proteins in exocrine granule exocytosis remains largely unknown. Here, we studied isoproterenol (IPR)-induced amylase release from parotid acinar cells to investigate the possible involvement of Rab33A, which was recently suggested to regulate exocytosis in hippocampal neurons and PC12 cells. Rab33A was endogenously expressed in parotid acinar cells and present in secretory granules and the Golgi body. Functional ablation of Rab33A with anti-Rab33A antibody or a dominant-negative Rab33A-T50N mutant significantly reduced IPR-induced amylase release. Our results indicated that Rab33A is a novel component of IPR-stimulated amylase secretion from parotid acinar cells. •Rab33A mRNA is expressed in exocrine parotid acinar cells.•Rab33A protein is localized in secretory granules and Golgi bodies.•Anti-Rab33A IgG inhibits β-stimulated amylase release from parotid acinar cells.•A dominant-negative mutant for Rab33A also reduces amylase release.•Rab33A is a novel component involved in amylase secretion from exocrine cells.
ISSN:0006-291X
1090-2104
DOI:10.1016/j.bbrc.2015.04.022