Differential Expression of Rab3 Isoforms during Differentiation of Pancreatic Acinar Cell Line AR42J

Rab3D regulates amylase levels, not agonist-induced amylase release, in AR42J cells

“…We and others have previously demonstrated that Rab3D is expressed in AR42J cells and that Rab3D levels increase upon treatment with Dex [23,28,30], suggesting that Rab3D plays a role in regulated exocytosis in these cells. It should also be noted that the other three Rab3 isoforms (Rab3A, Rab3B and Rab3C) are expressed in this cell line [23,28]. Interestingly, the four Rab3 isoforms do not co-localize with one another [23], suggesting that they may have distinct roles in these cells.…”

“…Immunocytochemical studies revealed that under basal conditions Rab3D colocalizes almost completely with amylase-containing granules in AR42J cells. Although the localization of Rab3D in AR42J cells has been described by others [23,28], the effect of secretory agonists on cell morphology has not been examined. We found that in response to treatment with CCK-8, the Rab3D-positive amylase-containing granules appear to move toward the periphery of the cell.…”

“…Rab3D, as well as the other three Rab3 isoforms (A, B and C), are all expressed in AR42J cells [23,28]. Moreover, Rab3D is upregulated in response to Dex treatment, suggesting a role for this protein in AR42J cells as they develop a more acinar cell-like phenotype [28][29][30]. The aim of the present study was to examine the role of Rab3D in AR42J cells.…”

“…CCK-8 induces amylase release from AR42J cells and, therefore, this cell line represents a convenient model for studying the molecular events involved in regulated secretion in exocrine cells. Rab3D, as well as the other three Rab3 isoforms (A, B and C), are all expressed in AR42J cells [23,28]. Moreover, Rab3D is upregulated in response to Dex treatment, suggesting a role for this protein in AR42J cells as they develop a more acinar cell-like phenotype [28][29][30].…”

Carboxyl-Methylation of Rab3D in the Rat Pancreatic Acinar Tumor Cell Line AR42J

“…This antiserum displayed no cross-reactivity with endogenous rab3A, rab3B and rab3C, but yielded a weak immunoreactive signal with bacterially expressed rab3B (data not shown). In a recent study, it has been demonstrated that rab3B is the major rab3 isoform expressed in AR42J cells and the only isoform whose mRNA expression is up-regulated by dexamethasone (19). This prompted us to determine in further detail which rab3 isoform(s) could be detected at the protein level in AR42J cells.…”