Evidence for the involvement of cAMP-dependent protein kinase in the exocytosis of amylase from parotid acinar cells.
To determine the role of cAMP-dependent protein kinase in the exocytosis of amylase from rat parotid acini, I studied the effects of various cAMP analogues on amylase release and protein phosphorylation in saponin-permeabilized parotid cells. The dose-dependent responses of amylase release and protein phosphorylation evoked by cAMP, dibutyryl-cAMP, and 8-chlorophenylthio-cAMP were closely correlated. Furthermore, when the permeabilized cells were incubated with a combination of site-selective cAMP analogues, such as N6-benzoyl-cAMP plus 8-thiomethyl-cAMP (RII-directed) or N6-benzoyl-cAMP plus 8-aminohexylamino-cAMP (RI-directed), synergistic stimulation of amylase release was clearly observed. As reported previously [T. Takuma (1988) Biochem. J. 256, 867-871], however, the protein phosphorylation evoked by 8-chlorophenylthio-cAMP was markedly inhibited by H-8 without a significant decrease in amylase release. These results suggest that cAMP-dependent protein kinase is involved in the regulation of amylase exocytosis, although the role of its catalytic subunit is still uncertain.
Takuma
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Department of Oral Biochemistry, School of Dentistry, Higashi Nippon Gakuen University, Hokkaido.
D000681:Amylases / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003994:Bucladesine / Q000494:pharmacology; D000242:Cyclic AMP / Q000031:analogs & derivatives / Q000494:pharmacology; D005089:Exocytosis / Q000502:physiology*; D066298:In Vitro Techniques; D007546:Isoquinolines / Q000494:pharmacology; D010306:Parotid Gland / Q000166:cytology* / Q000201:enzymology; D010766:Phosphorylation; D011494:Protein Kinases / Q000502:physiology*; D051381:Rats; D012503:Saponins / Q000494:pharmacology; D013873:Thionucleotides / Q000494:pharmacology
D007546:Isoquinolines; D012503:Saponins; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D003994:Bucladesine; C053177:N-(2-(methylamino)ethyl)-5-isoquinolinesulfonamide; D000242:Cyclic AMP; D011494:Protein Kinases; D000681:Amylases