RETRACTED: β-Arrestin-mediated PDE4 cAMP phosphodiesterase recruitment regulates β-adrenoceptor switching from G _s to G _i

Abstract

Phosphorylation of the ␤2 adrenoreceptor (␤2AR) by cAMP-activated protein kinase A (PKA) switches its predominant coupling from stimulatory guanine nucleotide regulatory protein (Gs) to inhibitory guanine nucleotide regulatory protein (G i). ␤-Arrestins recruit the cAMP-degrading PDE4 phosphodiesterases to the ␤2AR, thus controlling PKA activity at the membrane. Here we investigate a role for PDE4 recruitment in regulating G protein switching by the ␤2AR. In human embryonic kidney 293 cells overexpressing a recombinant ␤2AR, stimulation with isoprenaline recruits ␤-arrestins 1 and 2 as well as both PDE4D3 and PDE4D5 to the receptor and stimulates receptor phosphorylation by PKA. The PKA phosphorylation status of the ␤2AR is enhanced markedly when cells are treated with the selective PDE4-inhibitor rolipram or when they are transfected with a catalytically inactive PDE4D mutant (PDE4D5-D556A) that competitively inhibits isoprenaline-stimulated recruitment of native PDE4 to the ␤2AR. Rolipram and PDE4D5-D556A also enhance ␤2AR-mediated activation of extracellular signal-regulated kinases ERK1͞2. This is consistent with a switch in coupling of the receptor from G s to Gi, because the ERK1͞2 activation is sensitive to both inhibitors of PKA (H89) and G i (pertussis toxin). In cardiac myocytes, the ␤2AR also switches from G s to Gi coupling. Treating primary cardiac myocytes with isoprenaline induces recruitment of PDE4D3 and PDE4D5 to membranes and activates ERK1͞2. Rolipram robustly enhances this activation in a manner sensitive to both pertussis toxin and H89. Adenovirus-mediated expression of PDE4D5-D556A also potentiates ERK1͞2 activation. Thus, receptor-stimulated ␤-arrestinmediated recruitment of PDE4 plays a central role in the regulation of G protein switching by the ␤2AR in a physiological system, the cardiac myocyte.

A cluster of differentially expressed signal transduction genes identified by microarray analysis in a rat genetic model of alcoholism

“…17,18 Upon ligand binding b-arrestin also recruits cAMP phosphodiesterase type IV to the recetor-adenylate cyclase complex. 19 Both mechanisms lead to receptor desensitization and cAP signal termination. Consequently, b-arrestin downregulation may produce an increased responsiveness in several neurotransmitter systems and thus might offer a mechanism for the reported increased opiate and dopamine responsiveness in the AA line.…”

Arthropod D2 receptors positively couple with cAMP through the Gi/o protein family

“…First, DARs have been shown to couple with multiple G proteins in various heterologous and native systems (Kimura et al, 1995a;Sidhu et al, 1998;Zheng et al, 2003;O'Sullivan et al, 2004;Zhen et al, 2004;Kimura et al, 1995b). Moreover, GPCRs, including DARs, can switch G protein coupling over time in response to constant agonist application (Daaka et al, 1997;Baillie et al, 2003;Lezcano et al, 2000). Second, both the Gα and Gβγ subunits are known to mediate individual responses (Cabrera-Vera et al, 2003).…”

Protein–protein interactions of PDE4 family members — Functions, interactions and therapeutic value

“…The β-arrestin-dependent recruitment of PDE4D to the receptor and the local cAMP hydrolysis contributes to inhibition of PKA and reduction of receptor phosphorylation. Thus the β-arrestin-associated pool of PDE4D is associated with a switch from G S to activation of G i [33].…”

“…For example, the catalytically inactive PDE4D5-D556A prevents the isoproterenolinduced binding of the endogenous PDE4D5 to the β 2 -adrenoceptor complex. This is associated with an activation of ERK1/2 and thus caused by a local rise in cAMP, PKA activation and G protein switching from G s to G i (see 2.2) [33]. The dominant negative approach has for example also elucidated that PDE4D3 controls a cAMP microdomain at the β 1 -adrenoceptor in cardiac myocytes [50] and that PDE4D3 and PDE4C2 control AKAP-anchored PKA activity in the perinuclear region [51].…”