Selective SUMO modification of cAMP-specific phosphodiesterase-4D5 (PDE4D5) regulates the functional consequences of phosphorylation by PKA and ERK.
Enzymes from the PDE (phosphodiesterase) 4 cAMP-specific PDE family are crucial for the maintenance of compartmentalized cAMP responses in many cell types. Regulation of PDE activity can be achieved via post-translational modification such as phosphorylation by ERK (extracellular-signal-regulated kinase) MAPKs (mitogen-activated protein kinases) and PKA (protein kinase A). In the present paper, we report for the first time that PDE4 isoforms from the PDE4A and PDE4D subfamilies can be selectively modified by SUMO (small ubiquitin-related modifier). We have identified a single SUMO site within a consensus tetrapeptide motif, PsiKXE (where Psi represents a hydrophobic residue), which lies in the catalytic unit of these enzymes. SUMO modification of PDE4 at this site was observed upon overexpression of the SUMO E3 ligase PIASy [protein inhibitor of activated STAT (signal transducer and activator of transcription) Y] in HEK (human embryonic kidney)-293 cells and we identify PIASy as a novel binding partner for long PDE4 isoforms. Site-directed mutagenesis of the acceptor lysine residue ablated conjugation of PDE4 with SUMO, suggesting the presence of a single SUMO site in the first subdomain of the conserved PDE4 catalytic unit. This observation was supported by both cell-free in vitro SUMOylation assays and analysis of SUMOylated spot-immobilized peptide arrays. SUMO modification of long PDE4 isoforms serves to augment their activation by PKA phosphorylation and repress their inhibition by ERK phosphorylation. Following ligation of beta-adrenergic receptors, SUMOylation of PDE4 isoforms sufficiently amplified PKA-stimulated PDE4 activity to reduce markedly the PKA phosphorylation status of the beta2-adrenergic receptor. These results highlight a new means whereby cells might achieve the selective regulation of the activity of cAMP-specific PDE4 enyzmes.
Li
Xiang
X
Neuroscience and Molecular Pharmacology, Division of Integrative Biology, IBLS, Wolfson Building, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.
Vadrevu
Suryakiran
S
Dunlop
Allan
A
Day
Jon
J
Advant
Noopur
N
Troeger
Jessica
J
Klussmann
Enno
E
Jaffrey
Ellis
E
Hay
Ron T
RT
Adams
David R
DR
Houslay
Miles D
MD
Baillie
George S
GS
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4 / Q000235:genetics / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D006801:Humans; D008969:Molecular Sequence Data; D010766:Phosphorylation; D011487:Protein Conformation; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D025842:SUMO-1 Protein / Q000378:metabolism*; D015398:Signal Transduction
D020033:Protein Isoforms; D025842:SUMO-1 Protein; D017868:Cyclic AMP-Dependent Protein Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D054703:Cyclic Nucleotide Phosphodiesterases, Type 4