Signal transduction pathways mediating mucin secretion from intestinal goblet cells.
Cholinergic stimulation of the HT29-18N2 goblet cell line increased mucin secretion as assessed: (1) with a mucin-specific immunoassay, (2) using whole-mount immunocytochemistry, or (3) by morphometric quantification of intracellular mucous granule stores. Cholinergic stimulation did not, however, result in the apical plasmalemmal membrane cavitation that is characteristic of recent compound exocytotic activity. The response was not dependent on protein kinase C activation since it was not inhibited by the kinase C antagonist H7 or potentiated by the diacylglycerol kinase antagonist R59022. Calcium ionophore A23187 also accelerated mucin secretion by a noncompound exocytotic pathway. Activation of protein kinase C by phorbol 12-myristate 13-acetate, on the other hand, increased mucin secretion by a compound exocytotic pathway. The results provide insight into the signal transduction pathways underlying secretory responses of goblet cells observed in situ.
Division of Biological Sciences, University of Missouri, Columbia 65211.
T E
TE
Phillips
J
J
Wilson
D000230:Adenocarcinoma; D002118:Calcium / Q000378:metabolism; D003106:Colon / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D003110:Colonic Neoplasms; D003593:Cytoplasm / Q000187:drug effects / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000502:physiology; D005455:Fluorescent Antibody Technique; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009077:Mucins / Q000032:analysis / Q000187:drug effects / Q000378:metabolism*; D010277:Parasympathomimetics / Q000494:pharmacology; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013268:Stimulation, Chemical; D014407:Tumor Cells, Cultured / Q000166:cytology / Q000187:drug effects / Q000502:physiology
D009077:Mucins; D010277:Parasympathomimetics; D011493:Protein Kinase C; D002118:Calcium