scholarly journals Protein Phosphatase 1 Regulates Human Cytomegalovirus Protein Translation by Restraining AMPK Signaling

2021 ◽  
Vol 12 ◽  
Author(s):  
Carmen Stecher ◽  
Sanja Marinkov ◽  
Lucia Mayr-Harting ◽  
Ana Katic ◽  
Marie-Theres Kastner ◽  
...  
Keyword(s):  
Human Cytomegalovirus ◽  
Protein Phosphatase ◽  
Catalytic Domain ◽  
Human Fibroblasts ◽  
Elongation Factor ◽  
Early Time ◽  
Protein Translation ◽  
Protein Phosphatase 1 ◽  
Ampk Signaling ◽  
Protein Protein Interaction

Human cytomegalovirus (HCMV) carries the human protein phosphatase 1 (PP1) and other human proteins important for protein translation in its tegument layer for a rapid supply upon infection. However, the biological relevance behind PP1 incorporation and its role during infection is unclear. Additionally, PP1 is a difficult molecular target due to its promiscuity and similarities between the catalytic domain of multiple phosphatases. In this study, we circumvented these shortcomings by using 1E7-03, a small molecule protein–protein interaction inhibitor, as a molecular tool of noncatalytic PP1 inhibition. 1E7-03 treatment of human fibroblasts severely impaired HCMV replication and viral protein translation. More specifically, PP1 inhibition led to the deregulation of metabolic signaling pathways starting at very early time points post-infection. This effect was at least partly mediated by the prevention of AMP-activated protein kinase dephosphorylation, leading to elongation factor 2 hyperphosphorylation and reduced translation rates. These findings reveal an important mechanism of PP1 for lytic HCMV infection.

Apoptosis-associated tyrosine kinase scaffolding of protein phosphatase 1 and SPAK reveals a novel pathway for Na-K-2C1 cotransporter regulation

2007 ◽  
Vol 292 (5) ◽  
pp. C1809-C1815 ◽  
Author(s):  
Kenneth B. E. Gagnon ◽  
Roger England ◽  
Lisa Diehl ◽  
Eric Delpire
Keyword(s):  
Xenopus Laevis ◽  
Tyrosine Kinase ◽  
Protein Interaction ◽  
Protein Phosphatase ◽  
Catalytic Domain ◽  
Protein Phosphatase 1 ◽  
Xenopus Laevis Oocytes ◽  
Physical Interaction ◽  
Protein Protein Interaction ◽  
Key Residues

Previous work from our laboratory and others has established that Ste-20-related proline-alanine-rich kinase (SPAK/PASK) is central to the regulation of NKCC1 function. With no lysine (K) kinase (WNK4) has also been implicated in the regulation of NKCC1 activity through upstream activation of SPAK. Because previous studies from our laboratory also demonstrated a protein-protein interaction between SPAK and apoptosis-associated tyrosine kinase (AATYK), we explore here the possibility that AATYK is another component of the regulation of NKCC1. Heterologous expression of AATYK1 in NKCC1-injected Xenopus laevis oocytes markedly inhibited cotransporter activity under isosmotic conditions. Interestingly, mutation of key residues in the catalytic domain of AATYK1 revealed that the kinase activity does not play a role in the suppression of NKCC1 function. However, mutagenesis of the two SPAK-binding motifs in AATYK1 completely abrogated this effect. As protein phosphatase 1 (PP1) also plays a central role in the dephosphorylation and inactivation of NKCC1, we investigated the possibility that AATYK1 interacts with the phosphatase. We identified a PP1 docking motif in AATYK1 and demonstrated interaction using yeast-2-hybrid analysis. Mutation of a key valine residue (V1175) within this motif prevented protein-protein interaction. Furthermore, the physical interaction between PP1 and AATYK was required for inhibition of NKCC1 activity in Xenopus laevis oocytes. Taken together, our data are consistent with AATYK1 indirectly inhibiting the SPAK/WNK4 activation of the cotransporter by scaffolding an inhibitory phosphatase in proximity to a stimulatory kinase.

Elongation factor-1A1 is a novel substrate of the protein phosphatase 1-TIMAP complex

2015 ◽  
Vol 69 ◽  
pp. 105-113 ◽  
Author(s):  
Anita Boratkó ◽  
Margit Péter ◽  
Zsófia Thalwieser ◽  
Előd Kovács ◽  
Csilla Csortos
Keyword(s):  
Protein Phosphatase ◽  
Elongation Factor ◽  
Protein Phosphatase 1

scholarly journals Heat Shock-Induced Dephosphorylation of Eukaryotic Elongation Factor 1BδL by Protein Phosphatase 1

2021 ◽  
Vol 7 ◽  
Author(s):  
Taku Kaitsuka ◽  
Kazuhito Tomizawa ◽  
Masayuki Matsushita
Keyword(s):  
Heat Shock ◽  
Protein Phosphatase ◽  
Elongation Factor ◽  
Protein Phosphatase 1 ◽  
Cyclin Dependent Kinase ◽  
Proteotoxic Stress ◽  
Eukaryotic Elongation Factor ◽  
Functional Regulation

Several variant proteins are produced from EEF1D, including two representative proteins produced via alternative splicing machinery. One protein is the canonical translation eukaryotic elongation factor eEF1Bδ1, and the other is the heat shock-responsive transcription factor eEF1BδL. eEF1Bδ1 is phosphorylated by cyclin-dependent kinase 1 (CDK1), but the machinery controlling eEF1BδL phosphorylation and dephosphorylation has not been clarified. In this study, we found that both proteins were dephosphorylated under heat shock and proteotoxic stress, and this dephosphorylation was inhibited by okadaic acid. Using proteins with mutations at putative phosphorylated residues, we revealed that eEF1Bδ1 and eEF1BδL are phosphorylated at S133 and S499, respectively, and these residues are both CDK1 phosphorylation sites. The eEF1BδL S499A mutant more strongly activated HSPA6 promoter-driven reporter than the wild-type protein and S499D mutant. Furthermore, protein phosphatase 1 (PP1) was co-immunoprecipitated with eEF1Bδ1 and eEF1BδL, and PP1 dephosphorylated both proteins in vitro. Thus, this study clarified the role of phosphorylation/dephosphorylation in the functional regulation of eEF1BδL during heat shock.

scholarly journals Active ERK Contributes to Protein Translation by Preventing JNK-Dependent Inhibition of Protein Phosphatase 1

2006 ◽  
Vol 177 (3) ◽  
pp. 1636-1645 ◽  
Author(s):  
Martha M. Monick ◽  
Linda S. Powers ◽  
Thomas J. Gross ◽  
Dawn M. Flaherty ◽  
Christopher W. Barrett ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Protein Translation ◽  
Protein Phosphatase 1 ◽  
Dependent Inhibition

scholarly journals GADD34 is a modulator of autophagy during starvation

2020 ◽  
Vol 6 (39) ◽  
pp. eabb0205 ◽  
Author(s):  
Gennaro Gambardella ◽  
Leopoldo Staiano ◽  
Maria Nicoletta Moretti ◽  
Rossella De Cegli ◽  
Luca Fagnocchi ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Program Implementation ◽  
Protein Phosphatase ◽  
Protein Translation ◽  
Protein Phosphatase 1 ◽  
Autophagic Flux ◽  
Protein Synthesis Inhibition ◽  
Transcriptional Program ◽  
Mtorc1 Signaling ◽  
Main Regulator

Cells respond to starvation by shutting down protein synthesis and by activating catabolic processes, including autophagy, to recycle nutrients. This two-pronged response is mediated by the integrated stress response (ISR) through phosphorylation of eIF2α, which represses protein translation, and by inhibition of mTORC1 signaling, which promotes autophagy also through a stress-responsive transcriptional program. Implementation of such a program, however, requires protein synthesis, thus conflicting with general repression of translation. How is this mismatch resolved? We found that the main regulator of the starvation-induced transcriptional program, TFEB, counteracts protein synthesis inhibition by directly activating expression of GADD34, a component of the protein phosphatase 1 complex that dephosphorylates eIF2α. We discovered that GADD34 plays an essential role in autophagy by tuning translation during starvation, thus enabling lysosomal biogenesis and a sustained autophagic flux. Hence, the TFEB-GADD34 axis integrates the mTORC1 and ISR pathways in response to starvation.

scholarly journals Defective Ca2+ Handling Proteins Regulation During Heart Failure

2011 ◽  
pp. 27-37 ◽  
Author(s):  
S.-T. HU ◽  
G.-S. LIU ◽  
Y.-F. SHEN ◽  
Y.-L. WANG ◽  
Y. TANG ◽  
...  
Keyword(s):  
Heart Failure ◽  
Protein Phosphatase ◽  
Protein Phosphatase 1 ◽  
Down Regulation ◽  
Protein Protein Interaction ◽  
Fk506 Binding Protein ◽  
Direct Measurements ◽  
Associated Proteins ◽  
Phosphatase 2A ◽  
Rat Myocytes

Abnormal release of Ca2+ from sarcoplasmic reticulum (SR) via the cardiac ryanodine receptor (RyR2) may contribute to contractile dysfunction in heart failure (HF). We previously demonstrated that RyR2 macromolecular complexes from HF rat were significantly more depleted of FK506 binding protein (FKBP12.6). Here we assessed expression of key Ca2+ handling proteins and measured SR Ca2+ content in control and HF rat myocytes. Direct measurements of SR Ca2+ content in permeabilized cardiac myocytes demonstrated that SR luminal [Ca2+] is markedly lowered in HF (HF: ΔF/F0 = 26.4±1.8, n=12; control: ΔF/F0 = 49.2±2.9, n=10; P<0.01). Furthermore, we demonstrated that the expression of RyR2 associated proteins (including calmodulin, sorcin, calsequestrin, protein phosphatase 1, protein phosphatase 2A), Ca2+ATPase (SERCA2a), PLB phosphorylation at Ser16 (PLB-S16), PLB phosphorylation at Thr17 (PLB-T17), L-type Ca2+ channel (Cav1.2) and Na+-Ca2+ exchanger (NCX) were significantly reduced in rat HF. Our results suggest that systolic SR reduced Ca2+ release and diastolic SR Ca2+ leak (due to defective protein-protein interaction between RyR2 and its associated proteins) along with reduced SR Ca2+ uptake (due to down-regulation of SERCA2a, PLB-S16 and PLB-T17), abnormal Ca2+ extrusion (due to down-regulation of NCX) and defective Ca2+-induced Ca2+ release (due to down-regulation of Cav1.2) could contribute to HF.

scholarly journals Activity of protein phosphatases against initiation factor-2 and elongation factor-2

1990 ◽  
Vol 272 (1) ◽  
pp. 175-180 ◽  
Author(s):  
N T Redpath ◽  
C G Proud
Keyword(s):  
Phosphatase Activity ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Protein Phosphatase 2A ◽  
Elongation Factor ◽  
Protein Phosphatase 1 ◽  
Initiation Factor ◽  
Elongation Factor 2 ◽  
Initiation Factor 2 ◽  
Phosphatase 2A

The protein phosphatases active against phosphorylase a, elongation factor-2 (EF-2) and the alpha-subunit of initiation factor-2 (eIF-2) [eIF-2(alpha P)] were studied in extracts of rabbit reticulocytes. Swiss-mouse 3T3 fibroblasts and rat hepatocytes, by use of the specific phosphatase inhibitors okadaic acid and inhibitor proteins-1 and -2. In all three extracts tested, both phosphatase-1 and phosphatase-2A contributed to overall phosphatase activity against phosphorylase and eIF-2(alpha P), but phosphatase-2B and -2C did not. In contrast, only protein phosphatase-2A was active against EF-2. Furthermore, in hepatocytes there was substantial type-2C phosphatase activity against EF-2, but not against phosphorylase or eIF-2 alpha. These findings in cell extracts were borne out by data obtained by studying the activities of purified protein phosphatase-1 and -2A against eIF-2(alpha P) and eIF-2(alpha P) was a moderately good substrate for both enzymes (relative to phosphorylase a). In contrast, EF-2 was a very poor substrate for protein phosphatase-1, but was dephosphorylated faster than phosphorylase a by protein phosphatase-2A. The implications of these findings for the control of translation and their relationships to previous work are discussed.

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