title: Anchoring of protein kinase A-regulatory subunit IIalpha to subapically positioned centrosomes mediates apical bile canalicular lumen development in response to oncostatin M but not cAMP.
abstract: Oncostatin M and cAMP signaling stimulate apical surface-directed membrane trafficking and apical lumen development in hepatocytes, both in a protein kinase A (PKA)-dependent manner. Here, we show that oncostatin M, but not cAMP, promotes the A-kinase anchoring protein (AKAP)-dependent anchoring of the PKA regulatory subunit (R)IIalpha to subapical centrosomes and that this requires extracellular signal-regulated kinase 2 activation. Stable expression of the RII-displacing peptide AKAP-IS, but not a scrambled peptide, inhibits the association of RIIalpha with centrosomal AKAPs and results in the repositioning of the centrosome from a subapical to a perinuclear location. Concomitantly, common endosomes, but not apical recycling endosomes, are repositioned from a subapical to a perinuclear location, without significant effects on constitutive or oncostatin M-stimulated basolateral-to-apical transcytosis. Importantly, however, the expression of the AKAP-IS peptide completely blocks oncostatin M-, but not cAMP-stimulated apical lumen development. Together, the data suggest that centrosomal anchoring of RIIalpha and the interrelated subapical positioning of these centrosomes is required for oncostatin M-, but not cAMP-mediated, bile canalicular lumen development in a manner that is uncoupled from oncostatin M-stimulated apical lumen-directed membrane trafficking. The results also imply that multiple PKA-mediated signaling pathways control apical lumen development and that subapical centrosome positioning is important in some of these pathways.
authors.affiliation: Department of Cell Biology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Kacper A
authors.initials: KA
authors.lastname: Wojtal
authors.forename: Dick
authors.initials: D
authors.lastname: Hoekstra
authors.forename: Sven C D
authors.initials: SC
authors.lastname: van Ijzendoorn
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000494:pharmacology; D001648:Bile Canaliculi / Q000187:drug effects / Q000201:enzymology*; D003994:Bucladesine / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology; D016764:Cell Polarity / Q000187:drug effects*; D018385:Centrosome / Q000187:drug effects* / Q000201:enzymology*; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D004705:Endocytosis / Q000187:drug effects; D011992:Endosomes / Q000187:drug effects; D006801:Humans; D053683:Oncostatin M / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D013347:Subcellular Fractions / Q000187:drug effects
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D054754:Cyclic AMP-Dependent Protein Kinase RIIalpha Subunit; C517819:PRKAR2A protein, human; D053683:Oncostatin M; D003994:Bucladesine; D017868:Cyclic AMP-Dependent Protein Kinases