Mdm2 directs the ubiquitination of β-arrestin-sequestered cAMP phosphodiesterase-4D5 (original) (raw)

Li, Xiang, Baillie, George S. ORCID: https://orcid.org/0000-0003-2469-6316 and Houslay, Miles D.(2009) Mdm2 directs the ubiquitination of β-arrestin-sequestered cAMP phosphodiesterase-4D5.Journal of Biological Chemistry, 284(24), pp. 16170-16182. (doi: 10.1074/jbc.M109.008078)

Full text not currently available from Enlighten.

Publisher's URL: http://dx.doi.org/10.1074/jbc.M109.008078

Abstract

β-Arrestin plays a key role in regulating β₂-adrenoreceptor signaling by interdicting activation of adenylyl cyclase and selectively sequestering cAMP phosphodiesterase-4D5 (PDE4D5) for delivery of an active cAMP degrading system to the site of cAMP synthesis. Here we show that the β-agonist, isoprenaline, triggers the rapid and transient ubiquitination of PDE4D5 in primary cardiomyocytes, mouse embryo fibroblasts, and HEK293B2 cells constitutively expressing β₂ -adrenoceptors. Reconstitution analyses in β-arrestin1/2 double knockout cells plus small interference RNA knockdown studies indicate that a β-arrestin-scaffolded pool of the E3-ubiquitin ligase, Mdm2, mediates PDE4D5 ubiquitination. Critical for this is the ubiquitin-interacting motif located in the extreme C terminus of PDE4D5, which is specific to the PDE4D sub-family. In vitro SUMOylation of a PDE4D5 spot-immobilized peptide array, followed by a mutagenesis strategy, showed that PDE4D5 ubiquitination occurs at Lys-48, Lys-53, and Lys-78, which are located within its isoform-specific N-terminal region, as well as at Lys-140 located within its regulatory UCR1 module. We suggest that mono-ubiquitination at Lys-140 primes PDE4D5 for a subsequent cascade of polyubiquitination occurring within its isoform-specific N-terminal region at Lys-48, Lys-53, and Lys-78. PDE4D5 interacts with a non-ubiquitinated β-arrestin sub-population that is likely to be protected from Mdm2-mediated ubiquitination due to steric hindrance caused by sequestered PDE4D5. Ubiquitination of PDE4D5 elicits an increase in the fraction of PDE4D5 sequestered by β-arrestin in cells, thereby contributing to the fidelity of PDE4D5- β-arrestin interaction, as well as decreasing the fraction of PDE4D5 sequestered by the scaffolding protein, RACK1.

University Staff: Request a correction | Enlighten Editors: Update this record

Funder and Project Information

1

Phosphodiesterase-4 isoforms - intracellular targeting, regulation and potential therapeutic targets

Miles Houslay

G0600765

Institute of Neuroscience and Psychology

Deposit and Record Details