Sorting of a constitutive secretory protein to the regulated secretory pathway of exocrine cells.
Exocrine cells secrete granule proteins by regulated or constitutive-like secretory pathways. It is thought that all secretory proteins can enter immature secretory granules in exocrine cells. To test this hypothesis, we expressed the constitutive secretory protein secreted alkaline phosphatase (SEAP) in the exocrine cell line AR42J and compared its secretion to that of amylase, an endogenous regulated secretory protein. Secretion of SEAP and amylase were stimulated about 1.5-fold by substance P and 2-fold by barium chloride. In dexamethasone-treated cells, SEAP and amylase secretion were stimulated about 1.8-fold by substance P, 5-fold by barium chloride, and 4-fold by cholecystokinin-8. Cycloheximide reduced basal secretion of SEAP and amylase by 50%, increasing cholecystokinin-stimulated secretion to about 10-fold. Sodium butyrate induced expression of SEAP 2-fold but had no effect on stimulated secretion. These results suggest that SEAP is stored in secretory granules in AR42J cells.
Gorr
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SU
Department of Biological and Biophysical Sciences, University of Louisville School of Dentistry, Louisville, Kentucky, 40292, USA. sven.gorr@louisville.edu
Moore
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YR
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism*; D000681:Amylases / Q000378:metabolism; D000818:Animals; D017609:Barium Compounds / Q000494:pharmacology; D002087:Butyrates / Q000494:pharmacology; D002460:Cell Line; D002712:Chlorides / Q000494:pharmacology; D002766:Cholecystokinin / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D003594:Cytoplasmic Granules / Q000187:drug effects / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D051381:Rats; D013373:Substance P / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection
D017609:Barium Compounds; D002087:Butyrates; D002712:Chlorides; C024986:barium chloride; D013373:Substance P; D011189:Potassium Chloride; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D003907:Dexamethasone; D002766:Cholecystokinin; D003513:Cycloheximide; D000469:Alkaline Phosphatase; D000681:Amylases; D013755:Tetradecanoylphorbol Acetate