title: Aggregation and concentration-dependent sorting of exocrine regulated secretory proteins.
abstract: Sorting between the regulated and the constitutive secretory pathway in exocrine cells is thought to involve aggregation of regulated secretory proteins. This study demonstrates that, unlike endocrine secretory proteins, exocrine secretory proteins, including amylase, do not undergo homotypic aggregation under the conditions found in the sorting organelles. Also, unlike other exocrine proteins, amylase does not aggregate with chondroitin sulfate. Since amylase exhibits heterotypic aggregation, the role of protein concentration in amylase sorting was tested in AR42J cells. Secretion was stimulated with substance P and cholecystokinin from both untreated and dexamethasone-treated cells, with more efficient stimulation from dexamethasone-treated cells. These results indicate that amylase sorting is enhanced when its expression is stimulated by dexamethasone treatment.
authors.affiliation: Department of Biological and Biophysical Sciences, University of Louisville Health Sciences Center, KY 40292, USA.
authors.forename: S U
authors.initials: SU
authors.lastname: Gorr
authors.forename: S Y
authors.initials: SY
authors.lastname: Tseng
mesh_terms: D000681:Amylases / Q000737:chemistry* / Q000378:metabolism; D000818:Animals; D002460:Cell Line; D002809:Chondroitin Sulfates / Q000494:pharmacology; D003907:Dexamethasone / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000737:chemistry; D046911:Macromolecular Substances; D015388:Organelles / Q000378:metabolism; D010179:Pancreas / Q000378:metabolism* / Q000648:ultrastructure; D011189:Potassium Chloride / Q000494:pharmacology; D011388:Prolactin / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000378:metabolism; D051381:Rats; D013373:Substance P / Q000494:pharmacology
chemical_list: D007328:Insulin; D046911:Macromolecular Substances; D011506:Proteins; D013373:Substance P; D011189:Potassium Chloride; D003907:Dexamethasone; D011388:Prolactin; D002809:Chondroitin Sulfates; D000681:Amylases