Phosphorylation of Phosphoprotein Enriched in Astrocytes (PEA-15) Regulates Extracellular Signal-regulated Kinase-dependent Transcription and Cell Proliferation

University of California-San Diego, La Jolla, CA 92093-0726, USA.
Molecular Biology of the Cell (Impact Factor: 4.47). 09/2005; 16(8):3552-61. DOI: 10.1091/mbc.E04-11-1007
Source: PubMed


Cell cycle progression is dependent on the nuclear localization and transcriptional effects of activated extracellular signal-regulated kinase (ERK)1 and ERK2 mitogen-activated protein (MAP) kinases (ERK1/2). Phosphoprotein enriched in astrocytes (PEA-15) binds ERK1/2 and inhibits their nuclear localization, thus blocking cell proliferation. Here, we report that phosphorylation of PEA-15 blocks its interaction with ERK1/2 in vitro and in vivo and that phosphorylation of both Ser104 and Ser116 is required for this effect. Using phosphomimetic and nonphosphorylatable mutants of PEA-15, we found that PEA-15 phosphorylation abrogates its capacity to block the nuclear localization and transcriptional activities of ERK1/2; this phosphorylation therefore enables the proliferation of cells that express high levels of PEA-15. Additionally, we report that PEA-15 phosphorylation can modulate nontranscriptional activities of ERK1/2, such as the modulation of the affinity of integrin adhesion receptors. Finally, we used a novel anti-phospho-specific PEA-15 antibody to establish that PEA-15 is phosphorylated in situ in normal mammary epithelium. These results define a novel posttranslational mechanism for controlling the subcellular localization of ERK1/2 and for specifying the output of MAP kinase signaling.

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Available from: Angela Glading
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    • "Phosphorylation of PEA-15 at least at Ser104 blocks ERK1/2 binding, though phosphorylation of both sites is possibly required depending upon cell type. PEA-15 phosphorylation leads to an increase in the nuclear localisation of ERK1/2 and activation of nuclear transcription (Krueger et al., 2005; Renganathan et al., 2005). Using anisotropy methods, one study however suggests that the affinity of PEA-15 for ERK1/2 in vitro is not altered by PEA-15 phosphorylation (Callaway et al., 2007). "
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    ABSTRACT: Phosphoprotein enriched in astrocytes-15 (PEA-15) is a cytoplasmic protein that sits at an important junction in intracellular signalling and can regulate diverse cellular processes, such as proliferation and apoptosis, dependent upon stimulation. Regulation of these processes occurs by virtue of the unique interaction of PEA-15 with other signalling proteins. PEA-15 acts as a cytoplasmic tether for the mitogen-activated protein kinases, extracellular signal-regulated kinase 1/2 (ERK1/2) preventing nuclear localisation. In order to release ERK1/2, PEA-15 requires to be phosphorylated via several potential pathways. PEA-15 (and its phosphorylation state) therefore regulates many ERK1/2-dependent processes, including proliferation, via regulating ERK1/2 nuclear translocation. In addition, PEA-15 contains a death effector domain (DED) which allows interaction with other DED-containing proteins. PEA-15 can bind the DED-containing apoptotic adaptor molecule, Fas-associated death domain protein (FADD) which is also dependent on the phosphorylation status of PEA-15. PEA-15 binding of FADD can inhibit apoptosis as bound FADD cannot participate in the assembly of apoptotic signalling complexes. Through these protein-protein interactions, PEA-15-regulated cellular effects have now been investigated in a number of disease-related studies. Changes in PEA-15 expression and regulation have been observed in diabetes mellitus, cancer, neurological disorders and the cardiovascular system. These changes have been suggested to contribute to the pathology related to each of these disease states. As such, new therapeutic targets based around PEA-15 and its associated interactions are now being uncovered and could provide novel avenues for treatment strategies in multiple diseases.
    Full-text · Article · Mar 2014 · Pharmacology [?] Therapeutics
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    • "PED/PEA-15 lacks enzymatic function and mainly serves as a molecular adaptor. Indeed, it has been identified as an interactor for several signaling molecules including phospholipase D1 (Zhang et al., 2000), p90 ribosomal S6 protein kinase 2 (RSK2) (Vaidyanathan and Ramos, 2003), and extracellular signal regulated kinase 1/2 (ERK1/2) (Condorelli et al., 2002; Gaumont-Leclerc et al., 2004; Krueger et al., 2005; Gervais et al., 2006; Glading et al., 2007; Roth et al., 2007; Eckert et al., 2008). In particular, PED/PEA-15 binding to ERK1/2 prevents its nuclear translocation and determines cytosolic accumulation, thereby modifying its targeting to specific subsets of substrates (Formstecher et al., 2001). "
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    ABSTRACT: Cell migration is dependent on the control of signaling events that play significant roles in creating contractile force and in contributing to wound closure. We evaluated wound closure in fibroblasts from mice overexpressing (TgPED) or lacking ped/pea-15 (KO), a gene overexpressed in patients with type 2 diabetes. Cultured skin fibroblasts isolated from TgPED mice showed a significant reduction in the ability to recolonize wounded area during scratch assay, compared to control fibroblasts. This difference was observed both in the absence and in the presence of mytomicin C, an inhibitor of mitosis. In time-lapse experiments, TgPED fibroblasts displayed about twofold lower velocity and diffusion coefficient, as compared to controls. These changes were accompanied by reduced spreading and decreased formation of stress fibers and focal adhesion plaques. At the molecular level, TgPED fibroblasts displayed decreased RhoA activation and increased abundance of phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2). Inhibition of ERK1/2 activity by PD98059 restored RhoA activation, cytoskeleton organization and cell motility, and almost completely rescued wound closure of TgPED fibroblasts. Interestingly, skin fibroblasts isolated from KO mice displayed an increased wound closure ability. In vivo, healing of dorsal wounds was delayed in TgPED and accelerated in KO mice. Thus, PED/PEA-15 may affect fibroblast motility by a mechanism, at least in part, mediated by ERK1/2.
    Full-text · Article · May 2012 · Journal of Cellular Physiology
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    • "Cerebral ischemia induces Fas-mediated apoptosis and leads to neuronal cell death (Wetzel et al., 2008; Jia et al., 2009). Moreover, PEA- 15 binds extracellular signal-regulated kinase and regulates mitogen-activated protein kinase signaling (Krueger et al., 2005). We identified decreases in PEA-15 protein spots in MCAO-induced brain injury. "
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    ABSTRACT: PEA-15 is a small phosphoprotein (15 kDa) that is enriched in brain astrocytes. PEA-15 acts as an important modulator of cellular function including apoptosis and signal integration. This study investigated the expression of PEA-15 in focal cerebral ischemic injury. Cerebral ischemia was surgically induced in adult male rats by middle cerebral artery occlusion (MCAO), and brains were collected 24 hr after MCAO. A proteomic approach demonstrated decreases of PEA-15 protein spots in MCAO-operated animals in comparison to sham-operated animals. Western blot analysis clearly demonstrated that MCAO induces decreases in PEA-15 levels. We previously showed that glutamate toxicity induces cell death in a hippocampus-derived cell line (HT22). Glutamate exposure induces decreases of PEA-15 levels in HT22 cells. The results of this study suggest that focal cerebral ischemia induces cell death through down-regulation of PEA-15 protein.
    Preview · Article · Jan 2010
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