title: Regulation of nuclear PKA revealed by spatiotemporal manipulation of cyclic AMP.
abstract: Understanding how specific cyclic AMP (cAMP) signals are organized and relayed to their effectors in different compartments of the cell to achieve functional specificity requires molecular tools that allow precise manipulation of cAMP in these compartments. Here we characterize a new method using bicarbonate-activatable and genetically targetable soluble adenylyl cyclase to control the location, kinetics and magnitude of the cAMP signal. Using this live-cell cAMP manipulation in conjunction with fluorescence imaging and mechanistic modeling, we uncovered the activation of a resident pool of protein kinase A (PKA) holoenzyme in the nuclei of HEK-293 cells, modifying the existing dogma of cAMP-PKA signaling in the nucleus. Furthermore, we show that phosphodiesterases and A-kinase anchoring proteins (AKAPs) are critical in shaping nuclear PKA responses. Collectively, our data suggest a new model in which AKAP-localized phosphodiesterases tune an activation threshold for nuclear PKA holoenzyme, thereby converting spatially distinct second messenger signals to temporally controlled nuclear kinase activity.
authors.affiliation: Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
authors.forename: Vedangi
authors.initials: V
authors.lastname: Sample
authors.forename: Lisa M
authors.initials: LM
authors.lastname: DiPilato
authors.forename: Jason H
authors.initials: JH
authors.lastname: Yang
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ni
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Saucerman
authors.forename: Jin
authors.initials: J
authors.lastname: Zhang
mesh_terms: D054758:A Kinase Anchor Proteins / Q000378:metabolism; D000262:Adenylyl Cyclases / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D057809:HEK293 Cells / Q000187:drug effects; D020035:Holoenzymes / Q000378:metabolism; D006801:Humans; D008954:Models, Biological; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D015398:Signal Transduction; D017693:Sodium Bicarbonate / Q000494:pharmacology; D012995:Solubility
chemical_list: D054758:A Kinase Anchor Proteins; D004791:Enzyme Inhibitors; D020035:Holoenzymes; D017693:Sodium Bicarbonate; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D010727:Phosphoric Diester Hydrolases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D000262:Adenylyl Cyclases