期刊
AMERICAN JOURNAL OF PHYSIOLOGY-GASTROINTESTINAL AND LIVER PHYSIOLOGY
卷 294, 期 6, 页码 G1344-G1353出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpgi.00020.2008
关键词
translocation; PKC activator phorbol ester; PKC inhibitor
资金
- NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES [R21DK069702, R01DK054021, R01DK033850] Funding Source: NIH RePORTER
- NATIONAL INSTITUTE ON ALCOHOL ABUSE AND ALCOHOLISM [P50AA011999] Funding Source: NIH RePORTER
- NIAAA NIH HHS [P50 AA011999, 5 P60 AA-11999] Funding Source: Medline
- NIDDK NIH HHS [R01 DK-33850, R21 DK069702-01, R01 DK054021-02, DK-54021, R21 DK069702, R21 DK-69702, R01 DK054021, R01 DK033850] Funding Source: Medline
Isoforms of protein kinase C (PKC) have been shown to modulate some cellular responses such as pathological secretion and generation of inflammatory mediators during acute pancreatitis (AP). We propose that PKC also participates in premature zymogen activation within the pancreatic acinar cell, a key event in the initiation of AP. This hypothesis was examined in in vivo and cellular models of caerulein-induced AP using PKC activators and inhibitors. Phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA, 200 nM), a known activator of PKC, enhanced zymogen activation at both 0.1 nM and 100 nM caerulein, concentrations which mimic physiological and supraphysiological effects of the hormone cholecystokinin, respectively, in preparations of pancreatic acinar cells. Isoform-specific PKC inhibitors for PKC-delta and PKC-epsilon reduced supraphysiological caerulein-induced zymogen activation. Using a cell-free reconstitution system, we showed that inhibition of PKC-delta and -epsilon, reduced zymogen activation in both zymogen granule-enriched and microsomal fractions. In dispersed acinar cells, 100 nM caerulein stimulation caused PKC-delta and -epsilon isoform translocation to microsomal membranes using cell fractionation and immunoblot analysis. PKC translocation was confirmed with in vivo studies and immunofluorescence microscopy in pancreatic tissues from rats treated with or without 100 nM caerulein. PKC-epsilon redistributed from an apical to a supranuclear region following caerulein administration. The signal for PKC-epsilon overlapped with granule membrane protein, GRAMP-92, an endosomal/lysosomal marker, in a supranuclear region where zymogen activation takes place. These results indicate that PKC-delta and -epsilon isoforms translocate to specific acinar cell compartments and modulate zymogen activation.
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