title: The small GTPase Rab33A participates in regulation of amylase release from parotid acinar cells.
abstract: 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.
authors: Department of Dental Hygiene, College at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan; Department of Biochemistry, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan. Electronic address: imaiak@ngt.ndu.ac.jp.
authors: Akane
authors: A
authors: Imai
authors: Department of Histology, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan; Advanced Research Center, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan.
authors: Maiko
authors: M
authors: Tsujimura
authors: Department of Histology, School of Life Dentistry at Niigata, The Nippon Dental University, 1-8 Hamaura-cho, Chuo-ku, Niigata 951-8580, Japan.
authors: Sumio
authors: S
authors: Yoshie
authors: Laboratory of Membrane Trafficking Mechanisms, Department of Developmental Biology and Neurosciences, Graduate School of Life Sciences, Tohoku University, Aobayama, Aoba-ku, Sendai, Miyagi 980-8578, Japan.
authors: Mitsunori
authors: M
authors: Fukuda
mesh_terms: D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001483:Base Sequence; D017931:DNA Primers; D008297:Male; D010306:Parotid Gland / Q000166:cytology / Q000201:enzymology*; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar; D020691:rab GTP-Binding Proteins / Q000502:physiology*
chemical_list: D017931:DNA Primers; D000681:Amylases; C514094:Rab33A protein, rat; D020691:rab GTP-Binding Proteins
keywords: Amylase release; Intracellular distribution; Parotid; Rab33A; β-stimulation