title: Genetic deletion of Rab27B in pancreatic acinar cells affects granules size and has inhibitory effects on amylase secretion.
abstract: Small G protein Rab27B is expressed in various secretory cell types and plays a role in mediating secretion. In pancreatic acinar cells, Rab27B was found to be expressed on the zymogen granule membrane and by overexpression to regulate the secretion of zymogen granules. However, the effect of Rab27B deletion on the physiology of pancreatic acinar cells is unknown. In the current study, we utilized the Rab27B KO mouse model to better understand the role of Rab27B in the secretion of pancreatic acinar cells. Our data show that Rab27B deficiency had no obvious effects on the expression of major digestive enzymes and other closely related proteins, e.g. similar small G proteins, such as Rab3D and Rab27A, and putative downstream effectors. The overall morphology of acinar cells was not changed in the knockout pancreas. However, the size of zymogen granules was decreased in KO acinar cells, suggesting a role of Rab27B in regulating the maturation of secretory granules. The secretion of digestive enzymes was moderately decreased in KO acini, compared with the WT control. These data indicate that Rab27B is involved at a different steps of zymogen granule maturation and secretion, which is distinct from that of Rab3D.
authors: Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA.
authors: Yanan
authors: Y
authors: Hou
authors: Cell and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
authors: Stephen A
authors: SA
authors: Ernst
authors: Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA.
authors: Stephen I
authors: SI
authors: Lentz
authors: Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA; Internal Medicine, University of Michigan, Ann Arbor, MI 48109, USA. Electronic address: jawillms@umich.edu.
authors: John A
authors: JA
authors: Williams
mesh_terms: D061354:Acinar Cells; D000818:Animals; D017353:Gene Deletion; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D046790:Pancreas, Exocrine / Q000201:enzymology* / Q000648:ultrastructure; D055292:Pancreatic alpha-Amylases / Q000378:metabolism*; D022142:Secretory Vesicles / Q000201:enzymology* / Q000648:ultrastructure; D020691:rab GTP-Binding Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D000075745:rab27 GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins / Q000096:biosynthesis
chemical_list: D000075745:rab27 GTP-Binding Proteins; D055292:Pancreatic alpha-Amylases; C512958:Rab27b protein, mouse; C116711:Rab3d protein, mouse; C512962:Rab27a protein, mouse; D020691:rab GTP-Binding Proteins; D020692:rab3 GTP-Binding Proteins
keywords: Pancreatic acinar cells; Rab27B; Secretion; Zymogen granules