title: Dopamine-induced exocytosis of Na,K-ATPase is dependent on activation of protein kinase C-epsilon and -delta.
abstract: The purpose of this study was to define mechanisms by which dopamine (DA) regulates the Na,K-ATPase in alveolar epithelial type 2 (AT2) cells. The Na,K-ATPase activity increased by twofold in cells incubated with either 1 microM DA or a dopaminergic D(1) agonist, fenoldopam, but not with the dopaminergic D(2) agonist quinpirole. The increase in activity paralleled an increase in Na,K-ATPase alpha1 and beta1 protein abundance in the basolateral membrane (BLM) of AT2 cells. This increase in protein abundance was mediated by the exocytosis of Na,K-pumps from late endosomal compartments into the BLM. Down-regulation of diacylglycerol-sensitive types of protein kinase C (PKC) by pretreatment with phorbol 12-myristate 13-acetate or inhibition with bisindolylmaleimide prevented the DA-mediated increase in Na,K-ATPase activity and exocytosis of Na,K-pumps to the BLM. Preincubation of AT2 cells with either 2-[1-(3-dimethylaminopropyl)-5-methoxyindol-3-yl]-3-(1H-indol-3-yl)maleimide (Gö6983), a selective inhibitor of PKC-delta, or isozyme-specific inhibitor peptides for PKC-delta or PKC-epsilon inhibited the DA-mediated increase in Na,K-ATPase. PKC-delta and PKC-epsilon, but not PKC-alpha or -beta, translocated from the cytosol to the membrane fraction after exposure to DA. PKC-delta- and PKC-epsilon-specific peptide agonists increased Na,K-ATPase protein abundance in the BLM. Accordingly, dopamine increased Na,K-ATPase activity in alveolar epithelial cells through the exocytosis of Na,K-pumps from late endosomes into the basolateral membrane in a mechanism-dependent activation of the novel protein kinase C isozymes PKC-delta and PKC-epsilon.
authors.affiliation: Pulmonary and Critical Care Medicine, Northwestern University Medical School, Chicago, IL 60611, USA.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Ridge
authors.forename: Laura
authors.initials: L
authors.lastname: Dada
authors.forename: Emilia
authors.initials: E
authors.lastname: Lecuona
authors.forename: Alejandro M
authors.initials: AM
authors.lastname: Bertorello
authors.forename: Adrian I
authors.initials: AI
authors.lastname: Katz
authors.forename: Daria
authors.initials: D
authors.lastname: Mochly-Rosen
authors.forename: Jacob I
authors.initials: JI
authors.lastname: Sznajder
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004298:Dopamine / Q000378:metabolism / Q000494:pharmacology*; D015536:Down-Regulation; D011992:Endosomes / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis; D018818:Fenoldopam / Q000378:metabolism; D007211:Indoles / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008301:Maleimides / Q000494:pharmacology; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism* / Q000502:physiology; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: C465664:2-(1-(3-dimethylaminopropyl)-5-methoxyindol-3-yl)-3-(1H-indol-3-yl)maleimide; D004791:Enzyme Inhibitors; D007211:Indoles; D007527:Isoenzymes; D008301:Maleimides; C497260:Prkcd protein, rat; C497257:Prkce protein, rat; D011493:Protein Kinase C; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; D051745:Protein Kinase C-delta; D051744:Protein Kinase C-epsilon; D000254:Sodium-Potassium-Exchanging ATPase; D018818:Fenoldopam; D004298:Dopamine