Involvement of Rab4 in regulated exocytosis of rat pancreatic acini
Summary
This summary is machine-generated.Rab4 protein inhibits pancreatic acinar cell exocytosis. Cholecystokinin (CCK) regulates Rab4 activity via protein kinase C, influencing amylase release.
Area Of Science
- Cell biology
- Molecular biology
- Gastroenterology
Background
- Rab4, a small GTP-binding protein, is implicated in exocytosis.
- Its specific role in regulated exocytosis of pancreatic acini requires elucidation.
Purpose Of The Study
- To investigate the function of Rab4 in regulated exocytosis in pancreatic acini.
- To determine the regulatory mechanisms controlling Rab4 activity.
Main Methods
- Subcellular localization of Rab4 using Western blotting and immunohistochemistry.
- Functional assays in permeabilized pancreatic acini using Rab4 peptide and antibody.
- Assessment of Rab4 regulation by cholecystokinin (CCK) and 12-O-tetradecanoyl-phorbol 13-acetate (TPA) via GTP binding assays.
- Investigation of protein kinase C involvement using calphostin C.
Main Results
- Rab4 is localized to zymogen granule membranes.
- Rab4 inhibition enhanced calcium-stimulated amylase release, indicating an inhibitory role in exocytosis.
- CCK and TPA increased GTP binding to Rab4.
- Protein kinase C mediates CCK-stimulated Rab4 activation.
Conclusions
- Rab4 negatively regulates pancreatic acinar exocytosis.
- CCK controls Rab4 activity through a protein kinase C-dependent pathway.
View abstract on PubMed