Arrestin-dependent nuclear export of phosphodiesterase 4D promotes GPCR-induced nuclear cAMP signaling required for learning and memory

G protein-coupled receptors (GPCRs) promote the expression of immediate early genes required for learning and memory. Here, we showed that 132-adrenergic receptor (132AR) stimulation induced the nuclear export of phosphodiesterase 4D5 (PDE4D5), an enzyme that degrades the second messenger cAMP, to enable memory consolidation. We demonstrated that the endocytosis of 132AR phosphorylated by GPCR kinases (GRKs) mediat-ed arrestin3-dependent nuclear export of PDE4D5, which was critical for promoting nuclear cAMP signaling and gene expression in hippocampal neurons for memory consolidation. Inhibition of the arrestin3-PDE4D5 asso-ciation prevented 132AR-induced nuclear cAMP signaling without affecting receptor endocytosis. Direct PDE4 inhibition rescued 132AR-induced nuclear cAMP signaling and ameliorated memory deficits in mice expressing a form of the 132AR that could not be phosphorylated by GRKs. These data reveal how 132AR phosphorylated by endosomal GRK promotes the nuclear export of PDE4D5, leading to nuclear cAMP signaling, changes in gene expression, and memory consolidation. This study also highlights the translocation of PDEs as a mechanism to promote cAMP signaling in specific subcellular locations downstream of GPCR activation.

Automated summary

G protein-coupled receptors (GPCRs) promote the expression of immediate early genes required for learning and memory. β2-adrenergic receptor (β2AR) stimulation induces the nuclear export of phosphodiesterase 4D5 (PDE4D5), allowing for memory consolidation. This study reveals the mechanism of how β2AR phosphorylation by GRK promotes the nuclear export of PDE4D5, leading to nuclear cAMP signaling, changes in gene expression, and memory consolidation. The translocation of PDEs serves as a mechanism to promote cAMP signaling in specific subcellular locations downstream of GPCR activation.