title: nPKCepsilon, a P2Y2-R downstream effector in regulated mucin secretion from airway goblet cells.
abstract: Airway goblet cell mucin secretion is controlled by agonist activation of P2Y(2) purinoceptors, acting through Gq/PLC, inositol-1,4,5-trisphosphate (IP(3)), diacylglycerol, Ca(2+) and protein kinase C (PKC). Previously, we showed that SPOC1 cells express cPKCalpha, nPKCdelta, nPKCepsilon, and nPKCeta; of these, only nPKCdelta translocated to the membrane in correlation with mucin secretion (Abdullah LH, Bundy JT, Ehre C, Davis CW. Am J Physiol Lung Physiol 285: L149-L160, 2003). We have verified these results and pursued the identity of the PKC effector isoform by testing the effects of altered PKC expression on regulated mucin release using SPOC1 cell and mouse models. SPOC1 cells overexpressing cPKCalpha, nPKCdelta, and nPKCeta had the same levels of ATPgammaS- and phorbol-1,2-myristate-13-acetate (PMA)-stimulated mucin secretion as the levels in empty retroviral vector expressing cells. Secretagogue-induced mucin secretion was elevated only in cells overexpressing nPKCepsilon (14.6 and 23.5%, for ATPgammaS and PMA). Similarly, only SPOC1 cells infected with a kinase-deficient nPKCepsilon exhibited the expected diminution of stimulated mucin secretion, relative to wild-type (WT) isoform overexpression. ATPgammaS-stimulated mucin secretion from isolated, perfused mouse tracheas was diminished in P2Y(2)-R null mice by 82% relative to WT mice, demonstrating the utility of mouse models in studies of regulated mucin secretion. Littermate WT and nPKCdelta knockout (KO) mice had nearly identical levels of stimulated mucin secretion, whereas mucin release was nearly abolished in nPKCepsilon KO mice relative to its WT littermates. We conclude that nPKCepsilon is the effector isoform downstream of P2Y(2)-R activation in the goblet cell secretory response. The translocation of nPKCdelta observed in activated cells is likely not related to mucin secretion but to some other aspect of goblet cell biology.
authors.affiliation: CCystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, North Carolina 27599-7248, USA.
authors.forename: Camille
authors.initials: C
authors.lastname: Ehre
authors.forename: Yunxiang
authors.initials: Y
authors.lastname: Zhu
authors.forename: Lubna H
authors.initials: LH
authors.lastname: Abdullah
authors.forename: John
authors.initials: J
authors.lastname: Olsen
authors.forename: Keiichi I
authors.initials: KI
authors.lastname: Nakayama
authors.forename: Keiko
authors.initials: K
authors.lastname: Nakayama
authors.forename: Robert O
authors.initials: RO
authors.lastname: Messing
authors.forename: C William
authors.initials: CW
authors.lastname: Davis
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism; D000818:Animals; D002227:Carbazoles / Q000494:pharmacology; D002460:Cell Line; D004305:Dose-Response Relationship, Drug; D020397:Goblet Cells / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009077:Mucins / Q000378:metabolism*; D009154:Mutation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000378:metabolism; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021381:Protein Transport; D058910:Purinergic P2 Receptor Agonists; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D018048:Receptors, Purinergic P2 / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D058473:Receptors, Purinergic P2Y2; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014132:Trachea / Q000166:cytology / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D014162:Transfection
chemical_list: C465664:2-(1-(3-dimethylaminopropyl)-5-methoxyindol-3-yl)-3-(1H-indol-3-yl)maleimide; D002227:Carbazoles; D007211:Indoles; D008301:Maleimides; D009077:Mucins; C546386:P2ry2 protein, mouse; D047428:Protein Kinase Inhibitors; D058910:Purinergic P2 Receptor Agonists; D012333:RNA, Messenger; D018048:Receptors, Purinergic P2; D058473:Receptors, Purinergic P2Y2; C081021:Go 6976; C022571:adenosine 5'-O-(3-thiotriphosphate); D000255:Adenosine Triphosphate; C115197:calcium-independent protein kinase C; C081975:protein kinase C eta; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D013755:Tetradecanoylphorbol Acetate