title: Acidosis-induced V-ATPase trafficking in salivary ducts is initiated by cAMP/PKA/CREB pathway via regulation of Rab11b expression.
abstract: Changes in systemic acid-base homeostasis cause a series of organ-specific cellular responses, among them changes of acid-base transporter activities, and recruitment or retrieval of these transporters from intracellular pools to the plasma membrane and vice versa. The purpose of this study was to investigate the impact of protein phosphorylation in the acidosis-induced translocation of vacuolar-type H(+)-ATPase (V-ATPase) in salivary ducts and to identify molecular targets. Therefore, the human submandibular gland cell line HSG was exposed to acidosis and V-ATPase trafficking was investigated in the presence or absence of inhibitors and activators of sAC/PKA and Src/ERK signaling pathways. Putative target genes have been identified by RT-PCR and immunoblotting, and validated by loss-of-function experiments. Acidosis caused activation of cAMP/PKA and Src signaling and inhibition of either pathway significantly impaired acidosis-induced V-ATPase redistribution and incorporation into the plasma membrane. Activation of ERK1/2 was Src-independent, whereas activation of PKA caused phosphorylation of cAMP response element-binding (CREB) and activation to regulate Rab11b transcription. Loss-of-function of CREB down-regulated Rab11b transcript and protein and significantly impaired acidosis-induced V-ATPase translocation in HSG cells. These data demonstrate that the cAMP/PKA/CREB signaling pathway initiates acidosis-induced V-ATPase trafficking in salivary ducts via regulation of Rab11b expression and provide first evidence for a molecular mechanism underlying cAMP/PKA-dependent transporter trafficking that could account for accumulation and activity of transporters in other cellular systems as well.
authors.affiliation: Institute for Anatomy and Cell Biology, Department of Molecular Embryology, University of Freiburg, Albertstrasse 17, D-79104 Freiburg, Germany. oliver.oehlke@anat.uni-freiburg.de
authors.forename: Oliver
authors.initials: O
authors.lastname: Oehlke
authors.forename: Cornelius
authors.initials: C
authors.lastname: Schlosshardt
authors.forename: Melanie
authors.initials: M
authors.lastname: Feuerstein
authors.forename: Eleni
authors.initials: E
authors.lastname: Roussa
mesh_terms: D000138:Acidosis; D002460:Cell Line; D000242:Cyclic AMP / Q000378:metabolism*; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015151:Immunoblotting; D007546:Isoquinolines / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D021122:Protein Subunits / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018987:Salivary Ducts / Q000166:cytology / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013449:Sulfonamides / Q000494:pharmacology; D013997:Time Factors; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000099193:rab11 GTP-Binding Proteins
chemical_list: D000242:Cyclic AMP; D017362:Cyclic AMP Response Element-Binding Protein; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D007546:Isoquinolines; D008562:Membrane Glycoproteins; D047428:Protein Kinase Inhibitors; D021122:Protein Subunits; D013449:Sulfonamides; D025262:Vacuolar Proton-Translocating ATPases; D020691:rab GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C115163:CREB1 protein, human; C072237:TGOLN2 protein, human; C063509:N-(2-(4-bromocinnamylamino)ethyl)-5-isoquinolinesulfonamide