scholarly journals Further evidence that the tyrosine phosphorylation of glycogen synthase kinase-3 (GSK3) in mammalian cells is an autophosphorylation event

2004 ◽  
Vol 377 (1) ◽  
pp. 249-255 ◽  
Author(s):  
Adam COLE ◽  
Sheelagh FRAME ◽  
Philip COHEN
Keyword(s):  
Tyrosine Phosphorylation ◽  
Mammalian Cells ◽  
Protein Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Hek 293 ◽  
293 Cells ◽  
General Protein ◽  
The Stability

Phosphorylation of the endogenous GSK3α (glycogen synthase kinase-3α) at Tyr279 and GSK3β at Tyr216 was suppressed in HEK-293 or SH-SY5Y cells by incubation with pharmacological inhibitors of GSK3, but not by an Src-family inhibitor, 4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine (PP2), or a general protein tyrosine kinase inhibitor (genistein). GSK3β transfected into HEK-293 cells or Escherichia coli became phosphorylated at Tyr216, but catalytically inactive mutants did not. GSK3β expressed in insect Sf 21 cells or E. coli was extensively phosphorylated at Tyr216, but the few molecules lacking phosphate at this position could autophosphorylate at Tyr216in vitro after incubation with MgATP. The rate of autophosphorylation was unaffected by dilution and was suppressed by the GSK3 inhibitor kenpaullone. Wild-type GSK3β was unable to catalyse the tyrosine phosphorylation of catalytically inactive GSK3β lacking phosphate at Tyr216. Our results indicate that the tyrosine phosphorylation of GSK3 is an intramolecular autophosphorylation event in the cells that we have studied and that this modification enhances the stability of the enzyme.

Phosphorylation of tau by glycogen synthase kinase 3β in intact mammalian cells influences the stability of microtubules

2001 ◽  
Vol 312 (3) ◽  
pp. 141-144 ◽  
Author(s):  
Huachun Sang ◽  
Zhonghua Lu ◽  
Yulong Li ◽  
Binggen Ru ◽  
Wenqing Wang ◽  
...  
Keyword(s):  
Mammalian Cells ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3Β ◽  
The Stability

Protein-tyrosine Kinase p72 syk Is Activated by Platelet Activating Factor in Platelets

1994 ◽  
Vol 72 (06) ◽  
pp. 937-941 ◽  
Author(s):  
Karim Rezaul ◽  
Shigeru Yanagi ◽  
Kiyonao Sada ◽  
Takanobu Taniguchi ◽  
Hirohei Yamamura
Keyword(s):  
Tyrosine Kinase ◽  
Tyrosine Phosphorylation ◽  
Protein Tyrosine Kinase ◽  
Kinase Inhibitor ◽  
Critical Role ◽  
Platelet Activating Factor ◽  
Kinase Assay ◽  
Potential Candidate ◽  
Protein Tyrosine ◽  
Induced Aggregation

SummaryIt has been demonstrated that activation of platelets by platelet-activating factor (PAF) results in a dramatic increase in tyrosine phosphorylation of several cellular proteins. We report here that p72 syk is a potential candidate for the protein-tyrosine phosphorylation following PAF stimulation in porcine platelets. Immunoprecipitation kinase assay revealed that PAF stimulation resulted in a rapid activation of p72 syk which peaked at 10 s. The level of activation was found to be dose dependent and could be completely inhibited by the PAF receptor antagonist, CV3988. Phosphorylation at the tyrosine residues of p72 syk coincided with activation of yllsyk. Pretreatment of platelets with aspirin and apyrase did not affect PAF induced activation of p72 syk .Furthermore, genistein, a potent protein-tyrosine-kinase inhibitor, diminished PAF-induced p72 syk activation and Ca2+ mobilization as well as platelet aggregation. These results suggest that p72 syk may play a critical role in PAF-induced aggregation, possibly through regulation of Ca2+ mobilization.

COOH-terminal association of human smooth muscle calcium channel Cav1.2b with Src kinase protein binding domains: effect of nitrotyrosylation

2007 ◽  
Vol 293 (6) ◽  
pp. C1983-C1990 ◽  
Author(s):  
Minho Kang ◽  
Gracious R. Ross ◽  
Hamid I. Akbarali
Keyword(s):  
Smooth Muscle ◽  
Calcium Channel ◽  
Tyrosine Phosphorylation ◽  
Src Kinase ◽  
Sh2 Domain ◽  
Calcium Currents ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Binding Domains ◽  
293 Cells

The carboxyl terminus of the calcium channel plays an important role in the regulation of calcium entry, signal transduction, and gene expression. Potential protein-protein interaction sites within the COOH terminus of the L-type calcium channel include those for the SH3 and SH2 binding domains of c-Src kinase that regulates calcium currents in smooth muscle. In this study, we examined the binding sites involved in Src kinase-mediated phosphorylation of the human voltage-gated calcium channel (Cav) 1.2b (hCav1.2b) and the effect of nitrotyrosylation. Cotransfection of human embryonic kidney (HEK)-293 cells with hCav1.2b and c-Src resulted in tyrosine phosphorylation of the calcium channel, which was prevented by nitration of tyrosine residues by peroxynitrite. Whole cell calcium currents were reduced by 58 + 5% by the Src kinase inhibitor PP2 and 64 + 6% by peroxynitrite. Nitrotyrosylation prevented Src-mediated regulation of the currents. Glutathione S-transferase fusion protein of the distal COOH terminus of hCav1.2b (1809-2138) bound to SH2 domain of Src following tyrosine phosphorylation, while binding to SH3 required the presence of the proline-rich motif. Site-directed mutation of Y2134 prevented SH2 binding and resulted in reduced phosphorylation of hCav1.2b. Within the distal COOH terminus, single, double, or triple mutations of Y1837, Y1861, and Y2134 were constructed and expressed in HEK-293 cells. The inhibitory effects of PP2 and peroxynitrite on calcium currents were significantly reduced in the double mutant Y1837-2134F. These data demonstrate that the COOH terminus of hCav1.2b contains sites for the SH2 and SH3 binding of Src kinase. Nitrotyrosylation of these sites prevents Src kinase regulation and may be importantly involved in calcium influx regulation during inflammation.

scholarly journals ENERGY-BASED PHARMACOPHORE MODELING, VIRTUAL SCREENING, AND MOLECULAR DYNAMICS TO IDENTIFY POTENTIAL INHIBITORS FOR GLYCOGEN SYNTHASE KINASE 3 BETA

2018 ◽  
Vol 11 (2) ◽  
pp. 181
Author(s):  
Sheema Jb ◽  
Waheeta Hopper
Keyword(s):  
Molecular Dynamics ◽  
Wound Healing ◽  
Glycogen Synthase ◽  
Pharmacophore Model ◽  
Pharmacophore Modeling ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3 ◽  
Systemic Side Effects ◽  
The Stability ◽  
Potential Inhibitors

  Objective: Glycogen synthase kinase 3 beta (GSK3β) is one of the main targets for wound healing activity. Our objective is to identify novel inhibitors for GSK3β using in silico approach.Methods: Grid-based molecular docking, energy-based pharmacophore (e-pharmacophore) modeling, and molecular dynamics (MD) studies were performed for phytocompounds with GSK3β and compared with standard drugs using Schrodinger software.Results: The glide scores and the molecular interactions of the phytocompounds were well comparable to the standard drugs. The MD was performed for the target bound to the best scoring ligand, entagenic acid. The pharmacophore features of this docked complex were modeled as e-pharmacophore. The constructed e-pharmacophore model was screened against phytocompounds retrieved from literature to identify the ligands with similar pharmacophore features.Conclusion: The glide scores of fukinolic acid, cimicifugic acid, and linarin were −10.99, −8.28, and −7.25 kcal/mol, respectively. The further 50 nanoseconds MD study determined the stability of GSK3β-linarin complex. Nitrofurazone and sulfathiazole drugs can lead to systemic side effects. Hence, it is concluded that linarin could be a potent wound healing compound against GSK3β.

Rapid electrical stimulation causes alterations in cardiac intercellular junction proteins of cardiomyocytes

2014 ◽  
Vol 306 (9) ◽  
pp. H1324-H1333 ◽  
Author(s):  
Tadamitsu Nakashima ◽  
Tomoko Ohkusa ◽  
Yoko Okamoto ◽  
Masaaki Yoshida ◽  
Jong-Kook Lee ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Glycogen Synthase ◽  
Intercellular Junctions ◽  
Intercellular Junction ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3Β ◽  
Mechanical Coupling ◽  
Adhesion Junctions ◽  
The Stability ◽  
Arrhythmia Therapy

The intercellular junctions contain two complexes, adhesion junctions (AJ) and connexin (Cx) gap junctions (GJs). GJs provide the pathway for intercellular current flow. AJs mediate normal mechanical coupling and play an important role in the stability of GJs. We investigated the effects of rapid electrical stimulation (RES) on cardiac intercellular junctions, especially β-catenin and Cx43 alterations. We also studied the effects of ANG II receptor blockade on intercellular junction remodeling. Neonatal rats were euthanized by decapitation, and cardiomyocytes were prepared, cultured, and subjected to RES. We used real-time PCR, western blot analysis, and immunohistochemical methods. Conduction properties were examined by an extracellular potential mapping system. Cx43 protein expression in cardiomyocytes was significantly increased after 60 min. β-Catenin expression in the total cell fraction was significantly increased after 30 min. The expression level of β-catenin in the nucleus, which functions as a T cell factor/lymphocyte enhancer binding factor transcriptional activator of Cx43 with its degradation regulated by glycogen synthase kinase-3β, was dramatically increased after 10 min. Conduction velocity was increased significantly by RES for 60 min. Olmesartan prevented most these effects of RES. We showed an increase of phosphorylated glycogen synthase kinase-3β, which is phosphorylated by activated MAPKs and inhibits β-catenin degradation, was attenuated by olmesartan. The changes in β-catenin precede Cx43 GJ remodeling and might play an important role in the formation and stability of GJs. Olmesartan might be a new upstream arrhythmia therapy by modulating intercellular junction remodeling through the β-catenin signaling pathway.

scholarly journals Modulation of the glycogen synthase kinase-3 family by tyrosine phosphorylation.

1993 ◽  
Vol 12 (2) ◽  
pp. 803-808 ◽  
Author(s):  
K. Hughes ◽  
E. Nikolakaki ◽  
S.E. Plyte ◽  
N.F. Totty ◽  
J.R. Woodgett
Keyword(s):  
Tyrosine Phosphorylation ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase ◽  
Glycogen Synthase Kinase 3

GFP Fusions for Fluorescence Detection of Ca2+ and Ca2+-Calmodulin in Living Cells

1998 ◽  
Vol 4 (S2) ◽  
pp. 1008-1009
Author(s):  
Anthony Persechini
Keyword(s):  
Mammalian Cells ◽  
Dissociation Constants ◽  
Hek 293 ◽  
Fluorescent Indicators ◽  
Calmodulin Binding ◽  
Binding Domains ◽  
293 Cells ◽  
20 Nm ◽  
Binding Sequence ◽  
Expression In Mammalian Cells

We have previously described fluorescent indicators for Ca2+ (FIP-CAs) and (Ca2+)4-calmodulin (FIP-CBs) whose responses are based on a ligand-dependent decrease in fluorescence energy transfer (FRET) between GFP variants. The indicators for (Ca2+)4-calmodulin contain calmodulin-binding domains, those for Ca2+ also contain an integral calmodulin (CaM) domain. We have developed new versions of these indicators constructed with enhanced blue- and red-shifted GFPs suitable for stable and transient expression in mammalian cells, and have begun to use them to investigate the relationships between the free intracellular concentrations of Ca2+ ([Ca2+]i) and (Ca2+)4-CaM ([(Ca2+)4-CaM]i). When the blue-shifted fluorophore is excited at 380 nm these constructs exhibit an emission peak at 505 nm due to FRET to the red-shifted fluorophore.We have made FIP-CBs with dissociation constants for (Ca2+)4-CaM of 0.5 nM, 20 nM, 300 nM and > 20 μM by introducing R →Q substitutions in the CaM-binding sequence, and have stablyexpressed them in HEK-293 cells (Fig. 1).

Roles of the forkhead in rhabdomyosarcoma (FKHR) phosphorylation sites in regulating 14-3-3 binding, transactivation and nuclear targetting

2001 ◽  
Vol 354 (3) ◽  
pp. 605-612 ◽  
Author(s):  
Graham RENA ◽  
Alan R. PRESCOTT ◽  
Shaodong GUO ◽  
Philip COHEN ◽  
Terry G. UNTERMAN
Keyword(s):  
Glycogen Synthase ◽  
Transactivation Domain ◽  
Amino Acid Residues ◽  
Hek 293 ◽  
Nuclear Exclusion ◽  
Dna Binding Sites ◽  
293 Cells ◽  
Target Dna ◽  
Localization Signal ◽  
Endogenous Substrates

The transcription factor, forkhead in rhabdomyosarcoma (FKHR), is phosphorylated at three amino acid residues (Thr-24, Ser-256 and Ser-319) by protein kinase B (PKB)α. In the present study, mutagenesis has been used to study the roles of these phosphorylation events in regulating FKHR function in transfected HEK-293 cells. We find that the overexpression of FKHR[S256A] (where Ser-256 → Ala) blocks PKB activity in cells, preventing phosphorylation of the endogenous substrates FKHRL1 and glycogen synthase kinase-3. Thus some reported effects of overexpression of this and other mutants may be indirect, and result from suppression of the phosphorylation of other sites on FKHR and/or other PKB substrates. For example, we have shown that Thr-24 phosphorylation alone is critical for interaction with 14-3-3 proteins, and that the substitution of Ser-256 with an alanine residue indirectly blocks 14-3-3 protein binding by preventing the phosphorylation of Thr-24. We also found that insulin-like growth factor (IGF)-1 and serum-induced nuclear exclusion of FKHR[S256A] depends on the degree of overexpression of this mutant. Our results indicated that the interaction of FKHR with 14-3-3 proteins was not required for IGF-1-stimulated exclusion of FKHR from the nucleus. We present evidence in support of another mechanism, which depends on the phosphorylation of Ser-256 and may involve the masking of a nuclear localization signal. Finally, we have demonstrated that the failure of IGF-1 to suppress transactivation by FKHR[S256A] is not explained entirely by its failure to bind 14-3-3 proteins or to undergo nuclear exclusion. This result suggests that Ser-256 phosphorylation may also suppress transactivation by FKHR by yet another mechanism, perhaps by disrupting the interaction of FKHR with target DNA binding sites and/or the function of the transactivation domain.

Activation of the TASK-2 channel after cell swelling is dependent on tyrosine phosphorylation

2010 ◽  
Vol 299 (4) ◽  
pp. C844-C853 ◽  
Author(s):  
Signe Skyum Kirkegaard ◽  
Ian Henry Lambert ◽  
Steen Gammeltoft ◽  
Else Kay Hoffmann
Keyword(s):  
Tyrosine Phosphorylation ◽  
Tyrosine Kinases ◽  
Kinase Inhibitor ◽  
Tyrosine Phosphatase ◽  
Regulatory Volume Decrease ◽  
Janus Kinase ◽  
Cell Swelling ◽  
Hek 293 ◽  
Set Point ◽  
Phosphatase Inhibitor

The swelling-activated K+ currents ( IK,vol) in Ehrlich ascites tumor cells (EATC) has been reported to be through the two-pore domain (K2p), TWIK-related acid-sensitive K+ channel 2 (TASK-2). The regulatory volume decrease (RVD), following hypotonic exposure in EATC, is rate limited by IK,vol indicating that inhibition of RVD reflects inhibition of TASK-2. We find that in EATC the tyrosine kinase inhibitor genistein inhibits RVD by 90%, and that the tyrosine phosphatase inhibitor monoperoxo(picolinato)-oxo-vanadate(V) [mpV(pic)] shifted the volume set point for inactivation of the channel to a lower cell volume. Swelling-activated K+ efflux was impaired by genistein and the Src kinase family inhibitor 4-amino-5-(4-chloro-phenyl)-7-( t-butyl)pyrazolo[3,4- d]pyrimidine (PP2) and enhanced by the tyrosine phosphatase inhibitor mpV(pic). With the use of the TASK-2 inhibitor clofilium, it is demonstrated that mpV(pic) increased the volume-sensitive part of the K+ efflux 1.3 times. To exclude K+ efflux via a KCl cotransporter, cellular Cl− was substituted with NO3−. Also under these conditions K+ efflux was completely blocked by genistein. Thus tyrosine kinases seem to be involved in the activation of the volume-sensitive K+ channel, whereas tyrosine phosphatases appears to be involved in inactivation of the channel. Overexpressing TASK-2 in human embryonic kidney (HEK)-293 cells increased the RVD rate and reduced the volume set point. TASK-2 has tyrosine sites, and precipitation of TASK-2 together with Western blotting and antibodies against phosphotyrosines revealed a cell swelling-induced, time-dependent tyrosine phosphorylation of the channel. Even though we found an inhibiting effect of PP2 on RVD, neither Src nor the focal adhesion kinase (FAK) seem to be involved. Inhibitors of the epidermal growth factor receptor tyrosine kinases had no effect on RVD, whereas the Janus kinase (JAK) inhibitor cucurbitacin inhibited the RVD by 40%. It is suggested that the cytokine receptor-coupled JAK/STAT pathway is upstream of the swelling-induced phosphorylation and activation of TASK-2 in EATC.

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