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Src kinase pathways in extracellular Ca(2+)-dependent pancreatic enzyme secretion
Y Tsunoda1, H Yoshida, L Africa
1Department of Internal Medicine, University of Michigan, Ann Arbor 48109-0682, USA.
Biochemical and Biophysical Research Communications
|October 23, 1996
Summary
CCK-8 activates Src kinase pathways in rat pancreatic cells, influencing calcium entry and amylase secretion. These processes, dependent on extracellular calcium, involve specific protein tyrosine phosphorylations.
Area of Science:
- Cell biology
- Biochemistry
- Physiology
Background:
- Src kinase pathways play crucial roles in cellular signaling.
- Pancreatic acinar cells are responsible for digestive enzyme secretion.
Purpose of the Study:
- To investigate the functional roles of Src kinase pathways in rat pancreatic acinar cells.
- To elucidate the mechanism by which CCK-8 stimulates amylase secretion.
Main Methods:
- Dose-dependent analysis of Src kinase activity.
- Measurement of protein tyrosine kinase (PTK) activities.
- Assessment of extracellular calcium ([Ca2+]o) effects on cellular functions.
- Analysis of protein tyrosine phosphorylation patterns.
Main Results:
- CCK-8 increased Src kinase and PTK activities, sensitive to herbimycin A.
- CCK-8-stimulated amylase secretion and Ca2+ entry were dependent on [Ca2+]o.
- CCK-8 induced tyrosine phosphorylation of 60 KDa, 85 KDa, and 105 KDa proteins.
- [Ca2+]o removal abolished phosphorylation of p60 and p105, but not p85.
Conclusions:
- The p60 Src kinase and a p105 kinase (Src kinase kinase) are implicated in [Ca2+]o-dependent pancreatic exocytosis.
- Src kinase pathways are integral to CCK-8-mediated pancreatic acinar cell function.