scholarly journals Identification of a serine/threonine-specific protein phosphatase from the archaebacterium Sulfolobus solfataricus.

1993 ◽  
Vol 268 (9) ◽  
pp. 6505-6510
Author(s):  
P.J. Kennelly ◽  
K.A. Oxenrider ◽  
J. Leng ◽  
J.S. Cantwell ◽  
N. Zhao
Keyword(s):  
Protein Phosphatase ◽  
Sulfolobus Solfataricus ◽  
Specific Protein

scholarly journals The Negative Effect of Protein Phosphatase Z1 Deletion on the Oxidative Stress Tolerance of Candida albicans Is Synergistic with Betamethasone Exposure

2021 ◽  
Vol 7 (7) ◽  
pp. 540
Author(s):  
Ágnes Jakab ◽  
Tamás Emri ◽  
Kinga Csillag ◽  
Anita Szabó ◽  
Fruzsina Nagy ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Candida Albicans ◽  
Protein Phosphatase ◽  
Combined Treatment ◽  
Specific Protein ◽  
Ergosterol Biosynthesis ◽  
Acid Oxidation ◽  
Menadione Sodium Bisulfite ◽  
Rnaseq Data ◽  
Negative Effect

The glucocorticoid betamethasone (BM) has potent anti-inflammatory and immunosuppressive effects; however, it increases the susceptibility of patients to superficial Candida infections. Previously we found that this disadvantageous side effect can be counteracted by menadione sodium bisulfite (MSB) induced oxidative stress treatment. The fungus specific protein phosphatase Z1 (CaPpz1) has a pivotal role in oxidative stress response of Candida albicans and was proposed as a potential antifungal drug target. The aim of this study was to investigate the combined effects of CaPPZ1 gene deletion and MSB treatment in BM pre-treated C. albicans cultures. We found that the combined treatment increased redox imbalance, enhanced the specific activities of antioxidant enzymes, and reduced the growth in cappz1 mutant (KO) strain. RNASeq data demonstrated that the presence of BM markedly elevated the number of differentially expressed genes in the MSB treated KO cultures. Accumulation of reactive oxygen species, increased iron content and fatty acid oxidation, as well as the inhibiting ergosterol biosynthesis and RNA metabolic processes explain, at least in part, the fungistatic effect caused by the combined stress exposure. We suggest that the synergism between MSB treatment and CaPpz1 inhibition could be considered in developing of a novel combinatorial antifungal strategy accompanying steroid therapy.

Effects of Serine/Threonine Protein Phosphatases on Ion Channels in Excitable Membranes

2000 ◽  
Vol 80 (1) ◽  
pp. 173-210 ◽  
Author(s):  
Stefan Herzig ◽  
Joachim Neumann
Keyword(s):  
Ion Channels ◽  
Protein Phosphatase ◽  
Protein Phosphatases ◽  
Direct Interaction ◽  
Specific Protein ◽  
Biochemical Properties ◽  
Future Research ◽  
Regulatory Subunits ◽  
Phosphatase Inhibitors ◽  
Protein Phosphatase Inhibitors

This review deals with the influence of serine/threonine-specific protein phosphatases on the function of ion channels in the plasma membrane of excitable tissues. Particular focus is given to developments of the past decade. Most of the electrophysiological experiments have been performed with protein phosphatase inhibitors. Therefore, a synopsis is required incorporating issues from biochemistry, pharmacology, and electrophysiology. First, we summarize the structural and biochemical properties of protein phosphatase (types 1, 2A, 2B, 2C, and 3–7) catalytic subunits and their regulatory subunits. Then the available pharmacological tools (protein inhibitors, nonprotein inhibitors, and activators) are introduced. The use of these inhibitors is discussed based on their biochemical selectivity and a number of methodological caveats. The next section reviews the effects of these tools on various classes of ion channels (i.e., voltage-gated Ca2+ and Na+ channels, various K+ channels, ligand-gated channels, and anion channels). We delineate in which cases a direct interaction between a protein phosphatase and a given channel has been proven and where a more complex regulation is likely involved. Finally, we present ideas for future research and possible pathophysiological implications.

scholarly journals The kinetoplastid-specific phosphatase KPP1 attenuates PLK activity to facilitate flagellum inheritance in Trypanosoma brucei

2021 ◽  
Vol 14 (669) ◽  
pp. eabc6435
Author(s):  
Tai An ◽  
Huiqing Hu ◽  
Ziyin Li
Keyword(s):  
Cell Cycle ◽  
Trypanosoma Brucei ◽  
Protein Phosphatase ◽  
Catalytic Domain ◽  
Complex Structure ◽  
Cell Communication ◽  
Specific Protein ◽  
Activation Loop ◽  
Human Parasite ◽  
Complex Protein

Trypanosoma brucei, an important human parasite, has a flagellum that controls cell motility, morphogenesis, proliferation, and cell-cell communication. Inheritance of the newly assembled flagellum during the cell cycle requires the Polo-like kinase homolog TbPLK and the kinetoplastid-specific protein phosphatase KPP1, although whether TbPLK acts on KPP1 or vice versa has been unclear. Here, we showed that dephosphorylation of TbPLK on Thr125 by KPP1 maintained low TbPLK activity in the flagellum-associated hook complex structure, thereby ensuring proper flagellum positioning and attachment. This dephosphorylation event required the recognition of phosphorylated Thr198 in the activation loop of TbPLK by the N-terminal Plus3 domain of KPP1 and the dephosphorylation of phosphorylated Thr125 in TbPLK by the C-terminal catalytic domain of KPP1. Dephosphorylation of TbPLK by KPP1 prevented hyperphosphorylation of the hook complex protein TbCentrin2, thereby allowing timely dephosphorylation of phosphorylated TbCentrin2 for hook complex duplication and flagellum positioning and attachment. Thus, KPP1 attenuates TbPLK activity by dephosphorylating TbPLK to facilitate flagellum inheritance.

scholarly journals The STEP61 interactome reveals subunit-specific AMPA receptor binding and synaptic regulation

2019 ◽  
Vol 116 (16) ◽  
pp. 8028-8037 ◽  
Author(s):  
Sehoon Won ◽  
Salvatore Incontro ◽  
Yan Li ◽  
Roger A. Nicoll ◽  
Katherine W. Roche
Keyword(s):  
Ampa Receptors ◽  
Protein Tyrosine Phosphatase ◽  
Protein Phosphatase ◽  
Tyrosine Phosphatase ◽  
Hippocampal Slices ◽  
Specific Protein ◽  
Synaptic Proteins ◽  
Synaptic Currents ◽  
Synaptic Regulation ◽  
Binding Partners

Striatal-enriched protein tyrosine phosphatase (STEP) is a brain-specific protein phosphatase that regulates a variety of synaptic proteins, including NMDA receptors (NAMDRs). To better understand STEP’s effect on other receptors, we used mass spectrometry to identify the STEP61 interactome. We identified a number of known interactors, but also ones including the GluA2 subunit of AMPA receptors (AMPARs). We show that STEP61 binds to the C termini of GluA2 and GluA3 as well as endogenous AMPARs in hippocampus. The synaptic expression of GluA2 and GluA3 is increased in STEP-KO mouse brain, and STEP knockdown in hippocampal slices increases AMPAR-mediated synaptic currents. Interestingly, STEP61 overexpression reduces the synaptic expression and synaptic currents of both AMPARs and NMDARs. Furthermore, STEP61 regulation of synaptic AMPARs is mediated by lysosomal degradation. Thus, we report a comprehensive list of STEP61 binding partners, including AMPARs, and reveal a central role for STEP61 in differentially organizing synaptic AMPARs and NMDARs.

GL2 EXPRESSION MODULATOR, a plant specific protein phosphatase one interactor that binds phosphoinositides

2020 ◽  
Vol 528 (3) ◽  
pp. 607-611
Author(s):  
George W. Templeton ◽  
Jayde J. Johnson ◽  
Nicolas A. Sieben ◽  
Greg B. Moorhead
Keyword(s):  
Protein Phosphatase ◽  
Specific Protein

Predicted secondary and supersecondary structure for the serine-threonine-specific protein phosphatase family

1995 ◽  
Vol 21 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Thomas F. Jenny ◽  
Dietlind L. Gerloff ◽  
Mark A. Cohen ◽  
Steven A. Benner
Keyword(s):  
Protein Phosphatase ◽  
Specific Protein

scholarly journals Protein phosphatase 2C is responsible for VP-induced dephosphorylation of AQP2 serine 261

2017 ◽  
Vol 313 (2) ◽  
pp. F404-F413 ◽  
Author(s):  
Pui W. Cheung ◽  
Lars Ueberdiek ◽  
Jack Day ◽  
Richard Bouley ◽  
Dennis Brown
Keyword(s):  
Okadaic Acid ◽  
Membrane Trafficking ◽  
Protein Phosphatase ◽  
Specific Protein ◽  
Phosphatase Inhibitors ◽  
Phosphorylation State ◽  
Cellular Events ◽  
Erk Activity ◽  
In Cells

Aquaporin 2 (AQP2) trafficking is regulated by phosphorylation and dephosphorylation of serine residues in the AQP2 COOH terminus. Vasopressin (VP) binding to its receptor (V2R) leads to a cascade of events that result in phosphorylation of serine 256 (S256), S264, and S269, but dephosphorylation of S261. To identify which phosphatase is responsible for VP-induced S261 dephosphorylation, we pretreated cells with different phosphatase inhibitors before VP stimulation. Sanguinarine, a specific protein phosphatase (PP) 2C inhibitor, but not inhibitors of PP1, PP2A (okadaic acid), or PP2B (cyclosporine), abolished VP-induced S261 dephosphorylation. However, sanguinarine and VP significantly increased phosphorylation of ERK, a kinase that can phosphorylate S261; inhibition of ERK by PD98059 partially decreased baseline S261 phosphorylation. These data support a role of ERK in S261 phosphorylation but suggest that, upon VP treatment, increased phosphatase activity overcomes the increase in ERK activity, resulting in overall dephosphorylation of S261. We also found that sanguinarine abolished VP-induced S261 dephosphorylation in cells expressing mutated AQP2 S256A, suggesting that the phosphorylation state of S261 is independent of S256. Sanguinarine alone did not induce AQP2 membrane trafficking, nor did it inhibit VP-induced AQP2 membrane accumulation in cells and kidney tissues, suggesting that S261 does not play an observable role in acute AQP2 membrane accumulation. In conclusion, PP2C activity is required for S261 AQP2 dephosphorylation upon VP stimulation, which occurs independently of S256 phosphorylation. Understanding the pathways involved in modulating PP2C will help elucidate the role of S261 in cellular events involving AQP2.

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