title: An anchored PKA and PDE4 complex regulates subplasmalemmal cAMP dynamics.
abstract: The spatiotemporal regulation of cAMP can generate microdomains just beneath the plasma membrane where cAMP increases are larger and more dynamic than those seen globally. Real-time measurements of cAMP using mutant cyclic nucleotide-gated ion channel biosensors, pharmacological tools and RNA interference (RNAi) were employed to demonstrate a subplasmalemmal cAMP signaling module in living cells. Transient cAMP increases were observed upon stimulation of HEK293 cells with prostaglandin E1. However, pretreatment with selective inhibitors of type 4 phosphodiesterases (PDE4), protein kinase A (PKA) or PKA/A-kinase anchoring protein (AKAP) interaction blocked an immediate return of subplasmalemmal cAMP to basal levels. Knockdown of specific membrane-associated AKAPs using RNAi identified gravin (AKAP250) as the central organizer of the PDE4 complex. Co-immunoprecipitation confirmed that gravin maintains a signaling complex that includes PKA and PDE4D. We propose that gravin-associated PDE4D isoforms provide a means to rapidly terminate subplasmalemmal cAMP signals with concomitant effects on localized ion channels or enzyme activities.
authors.affiliation: Department of Pharmacology, University of Cambridge, Cambridge, UK.
authors.forename: Debbie
authors.initials: D
authors.lastname: Willoughby
authors.forename: Wei
authors.initials: W
authors.lastname: Wong
authors.forename: Jerome
authors.initials: J
authors.lastname: Schaack
authors.forename: John D
authors.initials: JD
authors.lastname: Scott
authors.forename: Dermot M F
authors.initials: DM
authors.lastname: Cooper
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000235:genetics / Q000378:metabolism*; D054758:A Kinase Anchor Proteins; D000527:Alprostadil / Q000378:metabolism; D000818:Animals; D015374:Biosensing Techniques; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D054815:Cyclic Nucleotide-Gated Cation Channels; D006801:Humans; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D007527:Isoenzymes / Q000235:genetics / Q000378:metabolism; D051379:Mice; D046912:Multiprotein Complexes; D018408:Patch-Clamp Techniques; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D051381:Rats; D011943:Receptors, Adrenergic, beta / Q000235:genetics / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D018797:Cell Cycle Proteins; D054815:Cyclic Nucleotide-Gated Cation Channels; D007473:Ion Channels; D007527:Isoenzymes; D046912:Multiprotein Complexes; D021122:Protein Subunits; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054684:Cyclic Nucleotide Phosphodiesterases, Type 3; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517376:PDE4D protein, human; D000527:Alprostadil