Identification of a multifunctional docking site on the catalytic unit of phosphodiesterase-4 (PDE4) that is utilised by multiple interaction partners

Abstract

Cyclic AMP (cAMP)-specific phosphodiesterase-4 (PDE4) enzymes underpin compartmentalised cAMP signalling by localising to distinct signalling complexes. PDE4 long isoforms can be phosphorylated by mitogen-activated protein kinase-activated protein kinase 2 (MK2), which attenuates activation of such enzymes through their phosphorylation by protein kinase A. Here we show that MK2 interacts directly with PDE4 long isoforms and define the sites of interaction. One is a unique site that locates within the regulatory upstream conserved region 1 (UCR1) domain and contains a core Phe141, Leu142 and Tyr143 (FLY) cluster (PDE4A5 numbering). Located with the second site is a critical core Phe693, Glu694, Phe695 (FQF) motif that is also employed in the sequestering of PDE4 long forms by an array of other signalling proteins, including the signalling scaffold β-arrestin, the tyrosyl kinase Lyn, the SUMOylation E2 ligase UBC9, the dynein regulator Lis1 (PAFAH1B1) and the protein kinase Erk. We propose that the FQF motif lies at the heart of a multifunctional docking (MFD) site located within the PDE4 catalytic unit. It is clear from our data that, as well as aiding fidelity of interaction, the MFD site confers exclusivity of binding between PDE4 and a single specific partner protein from the cohort of signalling proteins whose interaction with PDE4 involves the FQF motif.

Alzheimer’s-like pathology in aging rhesus macaques: Unique opportunity to study the etiology and treatment of Alzheimer’s disease

“…More recent studies revealed a loss of PDE4 regulation with advancing age (40). PDE4s are usually anchored to the correct location (e.g., the SER) by DISC1, but can become "unanchored" by MK2 inflammatory signaling (60,61), which may contribute to age-related loss of PDE4s from the dendritic compartment. Notably, inhibition of PDE4s can create an aged-like phenotype, reducing dlPFC neuronal firing (62) and increasing the production of pS214Tau in vitro (40).…”

“…Calcium dysregulation may drive tau pathology in multiple ways, including activation of kinases that phosphorylate tau, and by inducing inflammatory processes that remove the brakes on tau phosphorylation. For example, high levels of calcium signaling may increase MK2 activity through activation of upstream kinases like p38 (77,78), which can inhibit and unanchor PDE4s (60,61) (Fig. 4).…”

Mechanisms underlying the role of DISC1 in synaptic plasticity

“…Dynein activity is controlled by the multiprotein dynactin complex with which DISC1 associates (Kamiya et al 2005), and by the DISC1 binding partner LIS1 (Ozeki et al 2003;Brandon J Physiol 596.14 et al 2004) (Burdick et al 2008;Bradshaw et al 2009) and its accessory proteins NDE1 and NDEL1 (Cianfrocco et al 2015;Bradshaw & Hayashi, 2017). The DISC1 interactor and cAMP phosphodiesterase PDE4 also interacts with LIS1 Houslay et al 2017), NDE1 ) and NDEL1 (Collins et al 2008), and DISC1 and PDE4 control the composition of LIS1-NDE1-NDEL1 complexes via cAMP-dependent phosphorylation (Collins et al 2008;Bradshaw et al 2011;Murdoch et al 2011). It follows that DISC1 is likely to regulate retrograde cargo transport through interactions with LIS1, NDE1 and NDEL1 (Bradshaw et al 2011;Murdoch et al 2011), and that this mechanism may involve the second messenger cAMP, although the latter has yet to be proven.…”

Phosphodiesterase Type 4 anchoring regulates cAMP signaling to Popeye domain-containing proteins

“…2D). The assumption that the proteins interacted directly was further verified using far-western techniques, in which immobilized GST-coupled versions of known PDE4A binding proteins UBC9 and P75 NTR (Houslay et al, 2017) and POPDC1 were overlaid with MBP-PDE4A4 ( Fig. 2E).…”