scholarly journals Identification of the glycogenic compound 5-iodotubercidin as a general protein kinase inhibitor

1994 ◽  
Vol 299 (1) ◽  
pp. 123-128 ◽  
Author(s):  
D Massillon ◽  
W Stalmans ◽  
G van de Werve ◽  
M Bollen
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Biological Effects ◽  
Glycogen Synthesis ◽  
Specific Protein ◽  
Liver Cells ◽  
Protein Kinase Inhibitor ◽  
Casein Kinase 1

Addition of micromolar concentrations of the adenosine derivative 5-iodotubercidin (Itu) initiates glycogen synthesis in isolated hepatocytes by causing inactivation of phosphorylase and activation of glycogen synthase [Flückiger-Isler and Walter (1993) Biochem. J. 292, 85-91]. We report here that Itu also antagonizes the effects of saturating concentrations of glucagon and vasopressin on these enzymes. The Itu-induced activation of glycogen synthase could not be explained by the removal of phosphorylase a (a potent inhibitor of the glycogen-associated synthase phosphatase). When tested on purified enzymes, Itu did not affect the activities of the major Ser/Thr-specific protein phosphatases (PP-1, PP-2A, PP-2B and PP-2C), but it inhibited various Ser/Thr-specific protein kinases as well as the tyrosine kinase activity of the insulin receptor (IC50 between 0.4 and 28 microM at 10-15 microM ATP). Tubercidin, which did not affect glycogen synthase or phosphorylase in liver cells, was 300 times less potent as a protein kinase inhibitor. Kinetic analysis of the inhibition of casein kinase-1 and protein kinase A showed that Itu acts as a competitive inhibitor with respect to ATP, and as a mixed-type inhibitor with respect to the protein substrate. We propose that Itu inactivates phosphorylase and activates glycogen synthase by inhibiting phosphorylase kinase and various glycogen synthase kinases. Consistent with the broad specificity of Itu in vitro, this compound decreased the phosphorylation level of numerous phosphopolypeptides in intact liver cells. Our data suggest that at least some of the biological effects of Itu can be explained by an inhibition of protein kinases.

scholarly journals The selectivity of protein kinase inhibitors: a further update

2007 ◽  
Vol 408 (3) ◽  
pp. 297-315 ◽  
Author(s):  
Jenny Bain ◽  
Lorna Plater ◽  
Matt Elliott ◽  
Natalia Shpiro ◽  
C. James Hastie ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Specific Inhibitor ◽  
Protein Kinase Inhibitors ◽  
Mitogen Activated Protein Kinase ◽  
Casein Kinase 1

The specificities of 65 compounds reported to be relatively specific inhibitors of protein kinases have been profiled against a panel of 70–80 protein kinases. On the basis of this information, the effects of compounds that we have studied in cells and other data in the literature, we recommend the use of the following small-molecule inhibitors: SB 203580/SB202190 and BIRB 0796 to be used in parallel to assess the physiological roles of p38 MAPK (mitogen-activated protein kinase) isoforms, PI-103 and wortmannin to be used in parallel to inhibit phosphatidylinositol (phosphoinositide) 3-kinases, PP1 or PP2 to be used in parallel with Src-I1 (Src inhibitor-1) to inhibit Src family members; PD 184352 or PD 0325901 to inhibit MKK1 (MAPK kinase-1) or MKK1 plus MKK5, Akt-I-1/2 to inhibit the activation of PKB (protein kinase B/Akt), rapamycin to inhibit TORC1 [mTOR (mammalian target of rapamycin)–raptor (regulatory associated protein of mTOR) complex], CT 99021 to inhibit GSK3 (glycogen synthase kinase 3), BI-D1870 and SL0101 or FMK (fluoromethylketone) to be used in parallel to inhibit RSK (ribosomal S6 kinase), D4476 to inhibit CK1 (casein kinase 1), VX680 to inhibit Aurora kinases, and roscovitine as a pan-CDK (cyclin-dependent kinase) inhibitor. We have also identified harmine as a potent and specific inhibitor of DYRK1A (dual-specificity tyrosine-phosphorylated and -regulated kinase 1A) in vitro. The results have further emphasized the need for considerable caution in using small-molecule inhibitors of protein kinases to assess the physiological roles of these enzymes. Despite being used widely, many of the compounds that we analysed were too non-specific for useful conclusions to be made, other than to exclude the involvement of particular protein kinases in cellular processes.

scholarly journals Betulin, a Newly Characterized Compound in Acacia auriculiformis Bark, Is a Multi-Target Protein Kinase Inhibitor

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4599
Author(s):  
Augustine Ahmadu ◽  
Claire Delehouzé ◽  
Anas Haruna ◽  
Lukman Mustapha ◽  
Bilqis Lawal ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Growth Factor Receptor ◽  
Binding Pocket ◽  
Stem Bark ◽  
Janus Kinase ◽  
Myelogenous Leukemia ◽  
Acacia Auriculiformis

The purpose of this work is to investigate the protein kinase inhibitory activity of constituents from Acacia auriculiformis stem bark. Column chromatography and NMR spectroscopy were used to purify and characterize betulin from an ethyl acetate soluble fraction of acacia bark. Betulin, a known inducer of apoptosis, was screened against a panel of 16 disease-related protein kinases. Betulin was shown to inhibit Abelson murine leukemia viral oncogene homolog 1 (ABL1) kinase, casein kinase 1ε (CK1ε), glycogen synthase kinase 3α/β (GSK-3 α/β), Janus kinase 3 (JAK3), NIMA Related Kinase 6 (NEK6), and vascular endothelial growth factor receptor 2 kinase (VEGFR2) with activities in the micromolar range for each. The effect of betulin on the cell viability of doxorubicin-resistant K562R chronic myelogenous leukemia cells was then verified to investigate its putative use as an anti-cancer compound. Betulin was shown to modulate the mitogen-activated protein (MAP) kinase pathway, with activity similar to that of imatinib mesylate, a known ABL1 kinase inhibitor. The interaction of betulin and ABL1 was studied by molecular docking, revealing an interaction of the inhibitor with the ABL1 ATP binding pocket. Together, these data demonstrate that betulin is a multi-target inhibitor of protein kinases, an activity that can contribute to the anticancer properties of the natural compound and to potential treatments for leukemia.

A Casein kinase 1/Checkpoint kinase 1 pyrazolo-pyridine protein kinase inhibitor as novel activator of the p53 pathway

2013 ◽  
Vol 23 (20) ◽  
pp. 5578-5585 ◽  
Author(s):  
Anne-Sophie Huart ◽  
Barbara Saxty ◽  
Andy Merritt ◽  
Marta Nekulova ◽  
Stephen Lewis ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Kinase Inhibitor ◽  
Casein Kinase ◽  
Protein Kinase Inhibitor ◽  
P53 Pathway ◽  
Casein Kinase 1 ◽  
Checkpoint Kinase ◽  
Checkpoint Kinase 1

scholarly journals Molecular Basis for Ser/Thr Specificity in PKA Signaling

Cells ◽  
2020 ◽  
Vol 9 (6) ◽  
pp. 1548 ◽  
Author(s):  
Matthias J. Knape ◽  
Maximilian Wallbott ◽  
Nicole C. G. Burghardt ◽  
Daniela Bertinetti ◽  
Jan Hornung ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Substrate Specificity ◽  
Metal Ions ◽  
Protein Kinases ◽  
Molecular Basis ◽  
Kinase Inhibitor ◽  
Adenine Nucleotides ◽  
Catalytic Efficiency ◽  
Specific Protein ◽  
Divalent Metal Ions

cAMP-dependent protein kinase (PKA) is the major receptor of the second messenger cAMP and a prototype for Ser/Thr-specific protein kinases. Although PKA strongly prefers serine over threonine substrates, little is known about the molecular basis of this substrate specificity. We employ classical enzyme kinetics and a surface plasmon resonance (SPR)-based method to analyze each step of the kinase reaction. In the absence of divalent metal ions and nucleotides, PKA binds serine (PKS) and threonine (PKT) substrates, derived from the heat-stable protein kinase inhibitor (PKI), with similar affinities. However, in the presence of metal ions and adenine nucleotides, the Michaelis complex for PKT is unstable. PKA phosphorylates PKT with a higher turnover due to a faster dissociation of the product complex. Thus, threonine substrates are not necessarily poor substrates of PKA. Mutation of the DFG+1 phenylalanine to β-branched amino acids increases the catalytic efficiency of PKA for a threonine peptide substrate up to 200-fold. The PKA Cα mutant F187V forms a stable Michaelis complex with PKT and shows no preference for serine versus threonine substrates. Disease-associated mutations of the DFG+1 position in other protein kinases underline the importance of substrate specificity for keeping signaling pathways segregated and precisely regulated.

Structural origins of AGC protein kinase inhibitor selectivities: PKA as a drug discovery tool

2012 ◽  
Vol 393 (10) ◽  
pp. 1121-1129 ◽  
Author(s):  
Espen Åberg ◽  
Bjarte Lund ◽  
Alexander Pflug ◽  
Osman A.B.S.M. Gani ◽  
Ulli Rothweiler ◽  
...  
Keyword(s):  
Drug Discovery ◽  
Protein Kinase ◽  
Cyclic Amp ◽  
Protein Kinases ◽  
Kinase Inhibitor ◽  
Protein Kinase Inhibitor ◽  
Constitutive Activity ◽  
Inhibitor Selectivity ◽  
Kinase A

Abstract The era of structure-based protein kinase inhibitor design began in the early 1990s with the determination of crystal structures of protein kinase A (PKA, or cyclic AMP-dependent kinase). Although many other protein kinases have since been extensively characterized, PKA remains a prototype for studies of protein kinase active conformations. It serves well as a model for the structural properties of AGC subfamily protein kinases, clarifying inhibitor selectivity profiles. Its reliable expression, constitutive activity, simple domain structure, and reproducible crystallizability have also made it a useful surrogate for the discovery of inhibitors of both established and emerging AGC kinase targets.

scholarly journals The specificities of protein kinase inhibitors: an update

2003 ◽  
Vol 371 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Jenny BAIN ◽  
Hilary McLAUCHLAN ◽  
Matthew ELLIOTT ◽  
Philip COHEN
Keyword(s):  
Protein Kinase ◽  
Protein Kinases ◽  
Kinase Inhibitors ◽  
Glycogen Synthase ◽  
Specific Protein ◽  
Protein Kinase Inhibitors ◽  
Glycogen Synthase Kinase 3 ◽  
Dual Specificity ◽  
Combined Use ◽  
Dependent Protein

We have previously examined the specificities of 28 commercially available compounds, reported to be relatively selective inhibitors of particular serine/threonine-specific protein kinases [Davies, Reddy, Caivano and Cohen (2000) Biochem. J. 351, 95—105]. In the present study, we have extended this analysis to a further 14 compounds. Of these, indirubin-3′-monoxime, SP 600125, KT 5823 and ML-9 were found to inhibit a number of protein kinases and conclusions drawn from their use in cell-based assays are likely to be erroneous. Kenpaullone, Alsterpaullone, Purvalanol, Roscovitine, pyrazolopyrimidine 1 (PP1), PP2 and ML-7 were more specific, but still inhibited two or more protein kinases with similar potency. Our results suggest that the combined use of Roscovitine and Kenpaullone may be useful for identifying substrates and physiological roles of cyclin-dependent protein kinases, whereas the combined use of Kenpaullone and LiCl may be useful for identifying substrates and physiological roles of glycogen synthase kinase 3. The combined use of SU 6656 and either PP1 or PP2 may be useful for identifying substrates of Src family members. Epigallocatechin 3-gallate, one of the main polyphenolic constituents of tea, inhibited two of the 28 protein kinases in the panel, dual-specificity, tyrosine-phosphorylated and regulated kinase 1A (DYRK1A; IC50 = 0.33μM) and p38-regulated/activated kinase (PRAK; IC50 = 1.0μM).

scholarly journals SPOP-mediated ubiquitination and degradation of PDK1 suppresses AKT kinase activity and oncogenic functions

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Qiwei Jiang ◽  
Nana Zheng ◽  
Lang Bu ◽  
Xiaomei Zhang ◽  
Xiaoling Zhang ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Protein Kinase ◽  
Glycogen Synthase ◽  
Biological Effects ◽  
E3 Ligase ◽  
Dependent Manner ◽  
Akt Kinase ◽  
Casein Kinase 1

Abstract Background 3-phosphoinositide-dependent protein kinase-1 (PDK1) acts as a master kinase of protein kinase A, G, and C family (AGC) kinase to predominantly govern cell survival, proliferation, and metabolic homeostasis. Although the regulations to PDK1 downstream substrates such as protein kinase B (AKT) and ribosomal protein S6 kinase beta (S6K) have been well established, the upstream regulators of PDK1, especially its degrader, has not been defined yet. Method A clustered regularly interspaced short palindromic repeats (CRISPR)-based E3 ligase screening approach was employed to identify the E3 ubiquitin ligase for degrading PDK1. Western blotting, immunoprecipitation assays and immunofluorescence (IF) staining were performed to detect the interaction or location of PDK1 with speckle-type POZ protein (SPOP). Immunohistochemistry (IHC) staining was used to study the expression of PDK1 and SPOP in prostate cancer tissues. In vivo and in vitro ubiquitination assays were performed to measure the ubiquitination conjugation of PDK1 by SPOP. In vitro kinase assays and mass spectrometry approach were carried out to identify casein kinase 1 (CK1) and glycogen synthase kinase 3 (GSK3)-mediated PDK1 phosphorylation. The biological effects of PDK1 mutations and correlation with SPOP mutations were performed with colony formation, soft agar assays and in vivo xenograft mouse models. Results We identified that PDK1 underwent SPOP-mediated ubiquitination and subsequent proteasome-dependent degradation. Specifically, SPOP directly bound PDK1 by the consensus degron in a CK1/GSK3β-mediated phosphorylation dependent manner. Pathologically, prostate cancer patients associated mutations of SPOP impaired PDK1 degradation and thus activated the AKT kinase, resulting in tumor malignancies. Meanwhile, mutations that occurred around or within the PDK1 degron, by either blocking SPOP to bind the degron or inhibiting CK1 or GSK3β-mediated PDK1 phosphorylation, could markedly evade SPOP-mediated PDK1 degradation, and played potently oncogenic roles via activating the AKT kinase. Conclusions Our results not only reveal a physiological regulation of PDK1 by E3 ligase SPOP, but also highlight the oncogenic roles of loss-of-function mutations of SPOP or gain-of-function mutations of PDK1 in tumorigenesis through activating the AKT kinase.

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