scholarly journals The flip side of phospho‐signalling: Regulation of protein dephosphorylation and the protein phosphatase 2Cs

2019 ◽  
Vol 42 (10) ◽  
pp. 2913-2930 ◽  
Author(s):  
Govinal Badiger Bhaskara ◽  
Min May Wong ◽  
Paul E. Verslues
Keyword(s):  
Protein Phosphatase ◽  
Protein Dephosphorylation

scholarly journals Protein phosphatase-type 2B is involved in the regulation of the acrosome reaction but not in the temperature-dependent flagellar movement of fowl spermatozoa

Reproduction ◽  
2004 ◽  
Vol 128 (6) ◽  
pp. 783-787 ◽  
Author(s):  
K Ashizawa ◽  
G J Wishart ◽  
A R A H Ranasinghe ◽  
S Katayama ◽  
Y Tsuzuki
Keyword(s):  
Protein Phosphatase ◽  
Acrosome Reaction ◽  
Molecular Mechanisms ◽  
Dependent Manner ◽  
Temperature Dependent ◽  
Acrosomal Exocytosis ◽  
Protein Dephosphorylation ◽  
Dose Dependent ◽  
Protein Phosphatase Type ◽  
Stimulation Of

The motility and acrosomal integrity of fowl spermatozoa in TES/NaCl buffer, with or without homogenized inner perivitelline layers (IPVL) prepared from laid fowl eggs, was almost negligible at 40 °C. However, motility became vigorous even at 40 °C when 2 mmol CaCl2/l was added, and the acrosome reaction was also stimulated in the presence, but not in the absence, of IPVL. The presence of deltamethrin or fenvalerate, specific inhibitors of protein phosphatase-type 2B (PP2B), did not permit the restoration of motility at 40 °C but, in the presence of IPVL, these compounds stimulated the acrosome reaction in a dose-dependent manner in the range of 1–1000 nmol/l. These results suggest that IPVL is necessary for the activation of the acrosome reaction in fowl spermatozoa and that Ca2+ plays an important role in the stimulation of motility and acrosomal exocytosis. Furthermore, it appears that the intracellular molecular mechanisms for the regulation of the acrosome reaction of fowl spermatozoa are different from those for the restoration of motility, i.e. protein dephosphorylation by PP2B in the former but not in the latter case.

scholarly journals Protein Phosphatase 1α Mediates Ceramide-induced ERM Protein Dephosphorylation

2012 ◽  
Vol 287 (13) ◽  
pp. 10145-10155 ◽  
Author(s):  
Daniel Canals ◽  
Patrick Roddy ◽  
Yusuf A. Hannun
Keyword(s):  
Protein Phosphatase ◽  
Protein Dephosphorylation

scholarly journals Okadaic acid inhibition of KCl cotransport. Evidence that protein dephosphorylation is necessary for activation of transport by either cell swelling or N-ethylmaleimide.

1991 ◽  
Vol 97 (4) ◽  
pp. 799-817 ◽  
Author(s):  
M L Jennings ◽  
R K Schulz
Keyword(s):  
Okadaic Acid ◽  
Protein Phosphatase ◽  
Direct Action ◽  
Transport Protein ◽  
Cell Swelling ◽  
Kcl Cotransport ◽  
Rapid Removal ◽  
Protein Dephosphorylation ◽  
Protein Kinase Kinase

The mechanism of activation of KCl cotransport has been examined in rabbit red blood cells. Previous work has provided evidence that a net dephosphorylation is required for activation of transport by cell swelling. In the present study okadaic acid, an inhibitor of protein phosphatases, was used to test this idea in more detail. We find that okadaic acid strongly inhibits swelling-stimulated KCl cotransport. The IC50 for okadaic acid is approximately 40 nM, consistent with the involvement of type 1 protein phosphatase in transport activation. N-Ethylmaleimide (NEM) is well known to activate KCl cotransport in cells of normal volume. Okadaic acid, added before NEM, inhibits the activation of transport by NEM, indicating that a dephosphorylation is necessary for the NEM effect. Okadaic acid added after NEM inhibits transport only very slightly. After a brief exposure to NEM and rapid removal of unreacted NEM, KCl cotransport activates with a time delay that is similar to that for swelling activation. Okadaic acid causes a slight increase in the delay time. These findings are all consistent with the idea that NEM activates transport not by a direct action on the transport protein but by altering a phosphorylation-dephosphorylation cycle. The simplest hypothesis that is consistent with the data is that both cell swelling and NEM cause inhibition of a protein kinase. Kinase inhibition causes net dephosphorylation of some key substrate (not necessarily the transport protein); dephosphorylation of this substrate, probably by type 1 protein phosphatase, causes transport activation.

scholarly journals Inhibition of Protein Phosphatase 2A (PP2A) Prevents Mcl-1 Protein Dephosphorylation at the Thr-163/Ser-159 Phosphodegron, Dramatically Reducing Expression in Mcl-1-amplified Lymphoma Cells

2014 ◽  
Vol 289 (32) ◽  
pp. 21950-21959 ◽  
Author(s):  
Shanna K. Nifoussi ◽  
Nora R. Ratcliffe ◽  
Deborah L. Ornstein ◽  
Gary Kasof ◽  
Stefan Strack ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Protein Phosphatase 2A ◽  
Lymphoma Cells ◽  
Phosphatase 2A ◽  
Protein Dephosphorylation

scholarly journals Site-specific and temporally-regulated retinoblastoma protein dephosphorylation by protein phosphatase type 1

Oncogene ◽  
2001 ◽  
Vol 20 (29) ◽  
pp. 3776-3785 ◽  
Author(s):  
Ethel Rubin ◽  
Sibylle Mittnacht ◽  
Emma Villa-Moruzzi ◽  
John W Ludlow
Keyword(s):  
Protein Phosphatase ◽  
Retinoblastoma Protein ◽  
Site Specific ◽  
Protein Phosphatase Type 1 ◽  
Protein Dephosphorylation ◽  
Protein Phosphatase Type

scholarly journals Pptc7 is an essential phosphatase for promoting mammalian mitochondrial metabolism and biogenesis

2018 ◽  
Author(s):  
Natalie M. Niemi ◽  
Gary M. Wilson ◽  
Katherine A. Overmyer ◽  
F.-Nora Vögtle ◽  
Danielle C. Lohman ◽  
...  
Keyword(s):  
Lactic Acidosis ◽  
Protein Content ◽  
Mitochondrial Function ◽  
Protein Phosphatase ◽  
Mitochondrial Proteins ◽  
Mitochondrial Targeting ◽  
Transcript Levels ◽  
Protein Dephosphorylation ◽  
Functional Relevance ◽  
Mitochondrial Targeting Sequences

SUMMARYMitochondrial proteins are replete with phosphorylation; however, the origin, abundance, and functional relevance of these modifications are largely unclear. Nonetheless, mitochondria possess multiple resident phosphatases, suggesting that protein dephosphorylation may be broadly important for mitochondrial activities. To explore this, we deleted the poorly characterized matrix phosphatase Pptc7 from mice using CRISPR-Cas9 technology. Strikingly, Pptc7−/− mice exhibited marked hypoketotic hypoglycemia, elevated acylcarnitines, and lactic acidosis, and died soon after birth. Pptc7−/− tissues had significantly diminished mitochondrial size and protein content despite normal transcript levels, but consistently elevated phosphorylation on select mitochondrial proteins. These putative Pptc7 substrates include the protein translocase complex subunit Timm50, whose phosphorylation reduced import activity. We further find that phosphorylation in or near the mitochondrial targeting sequences of multiple proteins can disrupt their import rates and matrix processing. Overall, our data define Pptc7 as a protein phosphatase essential for proper mitochondrial function and biogenesis during the extrauterine transition.

scholarly journals Regulation of the phosphatase PP2B by protein–protein interactions

2016 ◽  
Vol 44 (5) ◽  
pp. 1313-1319 ◽  
Author(s):  
Patrick J. Nygren ◽  
John D. Scott
Keyword(s):  
Protein Interactions ◽  
Protein Phosphatase ◽  
Therapeutic Benefit ◽  
Protein Protein Interactions ◽  
Binding Motifs ◽  
Protein Substrates ◽  
Protein Phosphatase 2B ◽  
Anchoring Protein ◽  
Protein Dephosphorylation

Protein dephosphorylation is important for regulating cellular signaling in a variety of contexts. Protein phosphatase-2B (PP2B), or calcineurin, is a widely expressed serine/threonine phosphatase that acts on a large cross section of potential protein substrates when activated by increased levels of intracellular calcium in concert with calmodulin. PxIxIT and LxVP targeting motifs are important for maintaining specificity in response to elevated calcium. In the present study, we describe the mechanism of PP2B activation, discuss its targeting by conserved binding motifs and review recent advances in the understanding of an A-kinase anchoring protein 79/PP2B/protein kinase A complex's role in synaptic long-term depression. Finally, we discuss potential for targeting PP2B anchoring motifs for therapeutic benefit.

scholarly journals Protein Phosphorylation — Dephosphorylation in the Cytosol of Pea Mesophyll Cells

1986 ◽  
Vol 41 (9-10) ◽  
pp. 856-860 ◽  
Author(s):  
Ruth Hracky ◽  
Jürgen Soll
Keyword(s):  
Protein Phosphorylation ◽  
Protein Phosphatase ◽  
Kinase Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Alkaline Ph ◽  
Strong Decrease ◽  
Mesophyll Cells ◽  
Ph Optimum ◽  
Molecular Weights ◽  
Protein Dephosphorylation

Abstract Soluble protein kinase and protein phosphatase activities were localized in the cytosol of pea mesophyll cells using protoplasts fractionation techniques. The molecular weights of the phosphorylated cytosolic proteins, as determined by polyacrylamide gel electrophoresis, were 68, 55, 46, 38, 36, 30, 22 and 12 kDa. Histone and, to a much lesser extent, casein but not phosvitin were accepted as exogenous substrates. In every case serine served as acceptor amino acid for the phosphate residue. The protein phosphorylation activity had an alkaline pH optimum, and showed no response to varying Mg-2, Ca2+, Pi cyclo-AMP or calmodulin concentrations. The kinase activity was competitively inhibited by ADP and pyrophosphate with apparent Ki values of 0.5 and 0.17 mᴍ , respectively. High ATP concentrations (1-4 mᴍ) resulted in a strong decrease of radioactivity in the 32P labeled proteins. It is proposed that the ratio of protein phosphorylation to protein dephosphorylation is regulated by the ATP to ADP ratio in the cytosol.

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