scholarly journals Inhibition of protein phosphatase 1 reverses alcohol-induced ciliary dysfunction

2015 ◽  
Vol 308 (6) ◽  
pp. L577-L585 ◽  
Author(s):  
Michael E. Price ◽  
Jacqueline A. Pavlik ◽  
Joseph H. Sisson ◽  
Todd A. Wyatt
Keyword(s):  
Protein Phosphatase ◽  
Mucociliary Clearance ◽  
Specific Inhibitor ◽  
Alcohol Exposure ◽  
Inhibitory Effect ◽  
Regulatory Proteins ◽  
Protein Phosphatase 1 ◽  
Tissue Cell ◽  
Inhaled Particles ◽  
Phosphatase Activation

Airway mucociliary clearance is a first-line defense of the lung against inhaled particles and debris. Among individuals with alcohol use disorders, there is an increase in lung diseases. We previously identified that prolonged alcohol exposure impairs mucociliary clearance, known as alcohol-induced ciliary dysfunction (AICD). Cilia-localized enzymes, known as the ciliary metabolon, are key to the pathogenesis of AICD. In AICD, cyclic nucleotide-dependent ciliary kinases, which modulate phosphorylation to regulate cilia beat, are desensitized. We hypothesized that alcohol activates cilia-associated protein phosphatase 1 (PP1) activity, driving phosphorylation changes of cilia motility regulatory proteins. To test this hypothesis we identified the effects of prolonged alcohol exposure on phosphatase activity, cilia beat, and kinase responsiveness and cilia-associated phosphorylation targets when stimulated by β-agonist or cAMP. Prolonged alcohol activated PP1 and blocked cAMP-dependent cilia beat and protein kinase A (PKA) responsiveness and phosphorylation of a 29-kDa substrate of PKA. Importantly, prolonged alcohol-induced phosphatase activation was inhibited by the PP1 specific inhibitor, inhibitor-2 (I-2), restoring cAMP-stimulated cilia beat and PKA responsiveness and phosphorylation of the 29-kDa substrate. The I-2 inhibitory effect persisted in tissue, cell, and isolated cilia-organelle models, highlighting the association of ciliary metabolon-localized enzymes to AICD. Prolonged alcohol exposure drives ciliary metabolon-localized PP1 activation. PP1 activation modifies phosphorylation of a 29-kDa protein related to PKA activity. These data reinforce our previous findings that alcohol is acting at the level of the ciliary metabolon to cause ciliary dysfunction and identifies PP1 as a therapeutic target to prevent or reverse AICD.

scholarly journals N-Acetyl-β-D-glucopyranosylamine 6-phosphate is a specific inhibitor of glycogen-bound protein phosphatase 1

1997 ◽  
Vol 328 (2) ◽  
pp. 695-700 ◽  
Author(s):  
Mary BOARD
Keyword(s):  
Phosphatase Activity ◽  
Protein Phosphatase ◽  
Glycogen Phosphorylase ◽  
Glycogen Synthase ◽  
Specific Inhibitor ◽  
Competitive Inhibitor ◽  
Protein Phosphatase 1 ◽  
P Concentration ◽  
Glucose Analogue ◽  
Stimulation Of

Previous work has shown that the C-1-substituted glucose-analogue N-acetyl-β-D-glucopyranosylamine (1-GlcNAc) is a competitive inhibitor of glycogen phosphorylase (GP) and stimulates the inactivation of this enzyme by GP phosphatase. In addition to its effects on GP, 1-GlcNAc also prevents the glucose-led activation of glycogen synthase (GS) in whole hepatocytes. Such an effect on GS was thought to be due to the formation of 1-GlcNAc-6-P by the action of glucokinase within the hepatocyte [Board, Bollen, Stalmans, Kim, Fleet and Johnson (1995) Biochem. J. 311, 845-852]. To investigate this possibility further, a pure preparation of 1-GlcNAc-6-P was synthesized. The effects of the phosphorylated glucose analogue on the activity of protein phosphatase 1 (PP1), the enzyme responsible for dephosphorylation and activation of GS, are reported. During the present study, 1-GlcNAc-6-P inhibited the activity of the glycogen-bound form of PP1, affecting both the GSb phosphatase and GPa phosphatase activities. A level of 50% inhibition of GSb phosphatase activity was achieved with 85 μM 1-GlcNAc-6-P in the absence of Glc-6-P and with 135 μM in the presence of 10 mM Glc-6-P. At either Glc-6-P concentration, 500 μM 1-GlcNAc-6-P completely inhibited activity. The Glc-6-P stimulation of the GPa phosphatase activity of PP1 was negated by 1-GlcNAc-6-P but there was no inhibition of the basal rate in the absence of Glc-6-P. 1-GlcNAc-6-P inhibition was specific for the glycogen-bound form of PP1 and did not inhibit the GSb phosphatase activity of the cytosolic form of the enzyme. The present work explains our previous observations on the inactivating effects on GS of incubating whole hepatocytes with 1-GlcNAc. These observations have their basis in the inhibition of glycogen-bound PP1 by 1-GlcNAc-6-P. A novel inhibitor of PP1, specific for the glycogen-bound form of the enzyme, is presented.

Wortmannin inhibits insulin-stimulated activation of protein phosphatase 1 in rat cardiomyocytes

1999 ◽  
Vol 276 (5) ◽  
pp. H1520-H1526 ◽  
Author(s):  
Jane P. de Luca ◽  
Alice K. Garnache ◽  
Jill Rulfs ◽  
Thomas B. Miller
Keyword(s):  
Protein Phosphatase ◽  
Glycogen Synthase ◽  
Protein Phosphatase 1 ◽  
Rat Cardiomyocytes ◽  
Major Function ◽  
Pi3k Inhibitors ◽  
Protein Levels ◽  
Pi3k Activity ◽  
Insulin Dependent ◽  
Phosphatase Activation

A major function of insulin in target tissues is the activation of glycogen synthase. Phosphatidylinositol 3-kinase (PI3K) has been implicated in the insulin-induced activation of glycogen synthase, although the true function of this enzyme remains unclear. Data presented here demonstrate that the PI3K inhibitors wortmannin and LY-294002 block the insulin-stimulated activation of protein phosphatase 1 (PP1) in rat ventricular cardiomyocytes. This loss of phosphatase activation mimics that seen in diabetic cardiomyocytes, in which insulin stimulation fails to activate both PP1 and glycogen synthase. Interestingly, in diabetic cells, insulin stimulated PI3K activity to 300% of that in untreated controls, whereas this activity was increased by only 77% in normal cells. PI3K protein levels, however, were similar in normal and diabetic cells. Our results indicate that PI3K is involved in the stimulation of glycogen synthase activity by insulin through the regulation of PP1. The inability of insulin to stimulate phosphatase activity in diabetic cells, despite a significant increase in PI3K activity, suggests a defect in the insulin signaling pathway that contributes to the pathology of insulin-dependent diabetes.

scholarly journals Multiple roles for protein phosphatase 1 in regulating the Xenopus early embryonic cell cycle.

1992 ◽  
Vol 3 (6) ◽  
pp. 687-698 ◽  
Author(s):  
D H Walker ◽  
A A DePaoli-Roach ◽  
J L Maller
Keyword(s):  
Dna Synthesis ◽  
Protein Phosphatase ◽  
Specific Inhibitor ◽  
Embryonic Cell ◽  
S Phase ◽  
Multiple Roles ◽  
Protein Phosphatase 1 ◽  
Cell Cycles ◽  
M Phase ◽  
Cytostatic Factor

Using cytostatic factor metaphase II-arrested extracts as a model system, we show that protein phosphatase 1 is regulated during early embryonic cell cycles in Xenopus. Phosphatase 1 activity peaks during interphase and decreases shortly before the onset of mitosis. A second peak of activity appears in mitosis at about the same time that cdc2 becomes active. If extracts are inhibited in S-phase with aphidicolin, then phosphatase 1 activity remains high. The activity of phosphatase 1 appears to determine the timing of exit from S-phase and entry into M-phase; inhibition of phosphatase 1 by the specific inhibitor, inhibitor 2 (Inh-2), causes premature entry into mitosis, whereas exogenously added phosphatase 1 lengthens the interphase period. Analysis of DNA synthesis in extracts treated with Inh-2, but lacking the A- and B-type cyclins, shows that phosphatase 1 is also required for the process of DNA replication. These data indicate that phosphatase 1 is a component of the signaling pathway that ensures that M-phase is not initiated until DNA synthesis is complete.

scholarly journals Phactrs 1-4: A family of protein phosphatase 1 and actin regulatory proteins

2004 ◽  
Vol 101 (18) ◽  
pp. 7187-7192 ◽  
Author(s):  
P. B. Allen ◽  
A. T. Greenfield ◽  
P. Svenningsson ◽  
D. C. Haspeslagh ◽  
P. Greengard
Keyword(s):  
Protein Phosphatase ◽  
Regulatory Proteins ◽  
Protein Phosphatase 1 ◽  
Actin Regulatory Proteins

scholarly journals Regulation of Alternative Splicing by Reversible Protein Phosphorylation

2007 ◽  
Vol 283 (3) ◽  
pp. 1223-1227 ◽  
Author(s):  
Stefan Stamm
Keyword(s):  
Alternative Splicing ◽  
Protein Phosphorylation ◽  
Protein Phosphatase ◽  
Single Gene ◽  
Biological Properties ◽  
Regulatory Proteins ◽  
Protein Phosphatase 1 ◽  
Splice Sites ◽  
Reversible Protein Phosphorylation ◽  
Selection Of

The vast majority of human protein-coding genes are subject to alternative splicing, which allows the generation of more than one protein isoform from a single gene. Cells can change alternative splicing patterns in response to a signal, which creates protein variants with different biological properties. The selection of alternative splice sites is governed by the dynamic formation of protein complexes on the processed pre-mRNA. A unique set of these splicing regulatory proteins assembles on different pre-mRNAs, generating a “splicing” or “messenger ribonucleoprotein code” that determines exon recognition. By influencing protein/protein and protein/RNA interactions, reversible protein phosphorylation modulates the assembly of regulatory proteins on pre-mRNA and therefore contributes to the splicing code. Studies of the serine/arginine-rich protein class of regulators identified different kinases and protein phosphatase 1 as the molecules that control reversible phosphorylation, which controls not only splice site selection, but also the localization of serine/arginine-rich proteins and mRNA export. The involvement of protein phosphatase 1 explains why second messengers like cAMP and ceramide that control the activity of this phosphatase influence alternative splicing. The emerging mechanistic links between splicing regulatory proteins and known signal transduction pathways now allow in detail the understanding how cellular signals modulate gene expression by influencing alternative splicing. This knowledge can be applied to human diseases that are caused by the selection of wrong splice sites.

scholarly journals The structure of SDS22 provides insights into the mechanism of heterodimer formation with PP1

2018 ◽  
Vol 74 (12) ◽  
pp. 817-824 ◽  
Author(s):  
Meng S. Choy ◽  
Nicolas Bolik-Coulon ◽  
Tara L. Archuleta ◽  
Wolfgang Peti ◽  
Rebecca Page
Keyword(s):  
Protein Phosphatase ◽  
Intrinsically Disordered Proteins ◽  
Regulatory Proteins ◽  
Protein Phosphatase 1 ◽  
Disordered Proteins ◽  
Biological Targets ◽  
Intrinsically Disordered ◽  
Intrinsically Disordered Regions ◽  
Linear Motifs ◽  
Lrr Protein

Protein phosphatase 1 (PP1) dephosphorylates hundreds of key biological targets by associating with nearly 200 regulatory proteins to form highly specific holoenzymes. The vast majority of regulators are intrinsically disordered proteins (IDPs) and bind PP1 via short linear motifs within their intrinsically disordered regions. One of the most ancient PP1 regulators is SDS22, a protein that is conserved from yeast to mammals. Sequence analysis of SDS22 revealed that it is a leucine-rich repeat (LRR) protein, suggesting that SDS22, unlike nearly every other known PP1 regulator, is not an IDP but instead is fully structured. Here, the 2.9 Å resolution crystal structure of human SDS22 in space group P212121 is reported. SDS22 adopts an LRR fold with the horseshoe-like curvature typical for this family of proteins. The structure results in surfaces with distinct chemical characteristics that are likely to be critical for PP1 binding.

scholarly journals Protein phosphatase 1 modulates the inhibitory effect of With-no-Lysine kinase 4 on ROMK channels

2012 ◽  
Vol 303 (1) ◽  
pp. F110-F119 ◽  
Author(s):  
Dao-Hong Lin ◽  
Peng Yue ◽  
Jesse Rinehart ◽  
Peng Sun ◽  
Zhijian Wang ◽  
...  
Keyword(s):  
Protein Phosphatase ◽  
Collecting Duct ◽  
Inhibitory Effect ◽  
Protein Phosphatase 1 ◽  
Cortical Collecting Duct ◽  
Channel Activity ◽  
Serine Residue ◽  
Volume Depletion ◽  
K Secretion

With-no-Lysine kinase 4 (WNK4) inhibited ROMK (Kir1.1) channels and the inhibitory effect of WNK4 was abolished by serum-glucocorticoid-induced kinase 1 (SGK1) but restored by c-Src. The aim of the present study is to explore the mechanism by which Src-family tyrosine kinase (SFK) modulates the effect of SGK1 on WNK4 and to test the role of SFK-WNK4-SGK1 interaction in regulating ROMK channels in the kidney. Immunoprecipitation demonstrated that protein phosphatase 1 (PP1) binds to WNK4 at amino acid (aa) residues 695–699 (PP1#1) and at aa 1211–1215 (PP1#2). WNK4−PP1#1 and WNK4−PP1#2, in which the PP1#1 or PP1#2 binding site was deleted or mutated, inhibited ROMK channels as potently as WNK4. However, c-Src restored the inhibitory effect of WNK4 but not WNK4−PP1#1 on ROMK channels in the presence of SGK1. Moreover, expression of c-Src inhibited SGK1-induced phosphorylation of WNK4 but not WNK4−PP1#1 at serine residue 1196 (Ser1196). In contrast, coexpression of c-Src restored the inhibitory effect of WNK4−PP1#2 on ROMK in the presence of SGK1 and diminished SGK1-induced WNK4 phosphorylation at Ser1196 in cells transfected with WNK4−PP1#2. This suggests the possibility that c-Src regulates the interaction between WNK4 and SGK1 through activating PP1 binding to aa 695–9 thereby decreasing WNK4 phosphorylation and restoring the inhibitory effect of WNK4. This mechanism plays a role in suppressing ROMK channel activity during the volume depletion because inhibition of SFK or serine/threonine phosphatases increases ROMK channel activity in the cortical collecting duct of rats on a low-Na diet. We conclude that regulation of phosphatase activity by SFK plays a role in determining the effect of aldosterone on ROMK channels and on renal K secretion.

scholarly journals Regulation of protein phosphatase 1 by intrinsically disordered proteins

2012 ◽  
Vol 40 (5) ◽  
pp. 969-974 ◽  
Author(s):  
Meng S. Choy ◽  
Rebecca Page ◽  
Wolfgang Peti
Keyword(s):  
Protein Phosphatase ◽  
Intrinsically Disordered Proteins ◽  
Critical Role ◽  
Regulatory Proteins ◽  
Protein Phosphatase 1 ◽  
Disordered Proteins ◽  
Tertiary Structures ◽  
Binding Partner ◽  
Intrinsically Disordered ◽  
Biological Specificity

PP1 (protein phosphatase 1) is an essential serine/threonine phosphatase that plays a critical role in a broad range of biological processes, from muscle contraction to memory formation. PP1 achieves its biological specificity by forming holoenzymes with more than 200 known regulatory proteins. Interestingly, most of these regulatory proteins (≥70%) belong to the class of IDPs (intrinsically disordered proteins). Thus structural studies highlighting the interaction of these IDP regulatory proteins with PP1 are an attractive model system because it allows general parameters for a group of diverse IDPs that interact with the same binding partner to be identified, while also providing fundamental insights into PP1 biology. The present review provides a brief overview of our current understanding of IDP–PP1 interactions, including the importance of pre-formed secondary and tertiary structures for PP1 binding, as well as changes of IDP dynamics upon interacting with PP1.

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