title: Identification and characterization of PDE4A11, a novel, widely expressed long isoform encoded by the human PDE4A cAMP phosphodiesterase gene.
abstract: PDE4A11 is a novel cAMP-specific phosphodiesterase that is conserved in humans, mouse, rat, pig, and bat. Exon-1(4A11) encodes its unique, 81 amino acid N-terminal region. Reverse-transcriptase polymerase chain reaction performed across the splice junction, plus identification of expressed sequence tags, identifies PDE4A11 as a long isoform possessing UCR1 and UCR2 regulatory domains. Transcript analysis shows that PDE4A11 is widely expressed compared with PDE4A10 and PDE4A4B long isoforms. Truncation analysis identifies a putative promoter in a 250-base pair region located immediately upstream of the start site in Exon-1(4A11). Recombinant PDE4A11, expressed in COS-7 cells, is a 126-kDa protein localized predominantly around the nucleus and in membrane ruffles. PDE4A11 exhibits a K(m) for cAMP hydrolysis of 4 microM, with relative V(max) similar to that of PDE4A10 and PDE4A4B. PDE4A11 is dose-dependently inhibited by rolipram, 4-[(3-butoxy-4-methoxyphenyl)-methyl]-2-imidazolidinone (Ro 20-1724), cilomilast, roflumilast, and denbufylline, with IC(50) values of 0.7, 0.9, 0.03, 0.004, and 0.3 microM, respectively. Soluble and particulate PDE4A11 exhibit distinct rates of thermal inactivation (55 degrees C; T((0.5)) = 2.5 and 4.4 min, respectively). Elevating cAMP levels in COS-7 cells activates PDE4A11 concomitant with its phosphorylation at Ser119 by protein kinase A (PKA). PDE4A11 differs from PDE4A4 in sensitivity to cleavage by caspase-3, interaction with LYN SH3 domain, redistribution upon long-term rolipram challenge, and sensitivity to certain PDE4 inhibitors. PDE4A11, PDE4A10, and PDE4A4 all can interact with betaarrestin. PDE4A11 is a novel, widely expressed long isoform that is activated by PKA phosphorylation and shows a distinct intracellular localization, indicating that it may contribute to compartmentalized cAMP signaling in cells in which it is expressed.
authors.affiliation: Molecular Pharmacology Group, Division of Biochemistry and Molecular Biology, Institute of Biomedical and Life Sciences, Wolfson Building, University Avenue, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
authors.forename: Derek A
authors.initials: DA
authors.lastname: Wallace
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: Johnston
authors.forename: Elaine
authors.initials: E
authors.lastname: Huston
authors.forename: Douglas
authors.initials: D
authors.lastname: MacMaster
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Houslay
authors.forename: York-Fong
authors.initials: YF
authors.lastname: Cheung
authors.forename: Lachlan
authors.initials: L
authors.lastname: Campbell
authors.forename: Jenni E
authors.initials: JE
authors.lastname: Millen
authors.forename: Robin A
authors.initials: RA
authors.lastname: Smith
authors.forename: Irene
authors.initials: I
authors.lastname: Gall
authors.forename: Richard G
authors.initials: RG
authors.lastname: Knowles
authors.forename: Michael
authors.initials: M
authors.lastname: Sullivan
authors.forename: Miles D
authors.initials: MD
authors.lastname: Houslay
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D000242:Cyclic AMP / Q000502:physiology; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007424:Intracellular Fluid / Q000201:enzymology; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D015398:Signal Transduction
chemical_list: D007527:Isoenzymes; D010726:Phosphodiesterase Inhibitors; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4; C517355:PDE4A protein, human