scholarly journals The pleckstrin homology domains of protein kinase B and GRP1 (general receptor for phosphoinositides-1) are sensitive and selective probes for the cellular detection of phosphatidylinositol 3,4-bisphosphate and/or phosphatidylinositol 3,4,5-trisphosphate in vivo

1999 ◽  
Vol 344 (3) ◽  
pp. 929-936 ◽  
Author(s):  
Alexander GRAY ◽  
Jeroen V AN DER KAAY ◽  
C. Peter DOWNES
Keyword(s):  
Protein Kinase ◽  
Fusion Proteins ◽  
Protein Kinase B ◽  
Pleckstrin Homology ◽  
3T3 Cells ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Swiss 3T3

We have tested the binding specificities of the pleckstrin homology (PH) domains of protein kinase B (PKB) and GRP1 (general receptor for phosphoinositides-1), expressed as green fluorescent protein (GFP) fusion proteins [PH(PKB)GFP and PH(GRP1)GFP respectively] in HEK 293 cells and Swiss 3T3 cells, using confocal microscopy. Stimulation of HEK 293 cells with insulin caused a small, but sustained, increase in PtdIns(3,4,5)P3 levels, detected using a radioligand displacement assay, which was mirrored by the translocation of PH(PKB)GFP and PH(GRP1)GFP from the cytosol to the plasma membrane of live, transfected cells. Similar results were obtained using Swiss 3T3 cells stimulated with platelet-derived growth factor (PDGF) and expressing either PH(PKB)GFP or PH(GRP1)GFP. Biochemical analyses confirmed the accumulation of both PtdIns(3,4,5)P3 and PtdIns(3,4)P2 in response to PDGF, but only the latter was present at increased levels in Swiss 3T3 cells 30 min after an oxidative stress (1 mM H2O2). Concomitantly, only PH(PKB)GFP, and not PH(GRP1)GFP, was localized at plasma membranes after 30 min of treatment with H2O2. The fusion proteins appear accurately to report the spatial and temporal distribution of PtdIns(3,4,5)P3 and PtdIns(3,4)P2 in intact cells. These results establish the lipid selectivity of these PH domains in vivo, and further emphasize the overlapping, but distinct, second messenger roles of PtdIns(3,4,5)P3 and PtdIns(3,4)P2.

scholarly journals Calcitonin stimulates expression of the rat 25-hydroxyvitamin D3-24-hydroxylase (CYP24) promoter in HEK-293 cells expressing calcitonin receptor: identification of signaling pathways

2004 ◽  
Vol 32 (1) ◽  
pp. 87-98 ◽  
Author(s):  
XH Gao ◽  
PP Dwivedi ◽  
JL Omdahl ◽  
HA Morris ◽  
BK May
Keyword(s):  
Protein Kinase ◽  
Signaling Pathways ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Basal Expression ◽  
293 Cells ◽  
Gc Box

Regulation of the gene for renal 25-hydroxyvitamin D-24-hydroxylase (CYP24) is important for controlling the level of circulating 1,25-dihydroxyvitamin D3 (1,25(OH)2D3). We report here for the first time that the peptide hormone calcitonin significantly stimulates expression of a rat CYP24 promoter-luciferase construct in both transiently and stably transfected kidney HEK-293 cells. A GC box at -114/-101 and a CCAAT box at -62/-51 have been identified that underlie both basal expression of the CYP24 promoter and the calcitonin inductive response. Data from overexpression studies suggested that Sp1 and NF-Y are the proteins that function through the GC and CCAAT boxes respectively. ERK1/2 signaling pathways were not involved in the calcitonin-mediated response, since stimulation of the promoter was unaffected by the pharmacological ERK1/2 inhibitor PD98059 and by a dominant negative mutant of ERK1/2 (ERK1K71R). In contrast, calcitonin induction but not basal expression was dependent on protein kinase A and protein kinase C (PKC) activities with the inhibitors H89 and calphostin C lowering induction by 50-60%. The atypical PKC, PKCzeta contributes to calcitonin induction, but not to basal expression of the CYP24 promoter, since overexpression of a dominant negative clone PKCzetaK281 M lowered induction by 50%. Cotransfection of a dominant negative form of Ras resulted in calcitonin-mediated induction being reduced also by about 50%. A Ras-PKCzeta signaling pathway for calcitonin action is proposed, which acts through the GC box. The findings have been extrapolated to the in vivo situation where we suggest that induction of renal CYP24 by calcitonin could be important under hypercalcemic conditions thus contributing to the lowering of circulating 1,25(OH)2D3 levels.

scholarly journals A role for the actin cytoskeleton in the hormonal and growth-factor-mediated activation of protein kinase B

2000 ◽  
Vol 352 (3) ◽  
pp. 617-622 ◽  
Author(s):  
Karine PEYROLLIER ◽  
Eric HAJDUCH ◽  
Alexander GRAY ◽  
Gary J. LITHERLAND ◽  
Alan R. PRESCOTT ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Growth Factor ◽  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
Fluorescent Protein ◽  
Protein Kinase B ◽  
Cytochalasin D ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells

We show here that cytochalasin D-induced depolymerization of actin filaments markedly reduces the stimulus-dependent activation of protein kinase B (PKB) in four different cell types (HEK-293 cells, L6 myotubes, 3T3-L1 adipocytes and U87MG cells). HEK-293 cells expressing the pleckstrin homology (PH) domains of PKB and general receptor for phosphoinositides-1 (GRP1) fused to green fluorescent protein (GFP) were used to monitor production of 3-phosphoinositides in the plasma membrane. Disassembly of the actin cytoskeleton significantly reduced the insulin-mediated translocation of both PKB-PHŐGFP and GRP1-PHŐGFP to the plasma membrane, consistent with diminished synthesis of 3-phosphoinositides. Actin depolymerization did not affect the hormonal activation of phosphoinositide 3-kinase (PI 3-kinase), and since cytochalasin D treatment also led to reduced platelet-derived growth factor (PDGF)-induced phosphorylation of PKB in U87MG cells, a PTEN (phosphatase and tensin homologue deleted on chromosome 10) null cell line, lipid phosphatase activity was unlikely to account for any reduction in cellular 3-phosphoinositides. Withdrawal of cytochalasin D from the extracellular medium induced actin filament repolymerization, and reinstated both the recruitment of PHŐGFP fusion proteins to the plasma membrane and PKB activation in response to insulin and PDGF. Our findings indicate that an intact actin network is a crucial requirement for PI 3-kinase-mediated production of 3-phosphoinositides and, therefore, for the activation of PKB.

scholarly journals Insulin-induced phospholipase D1 and phospholipase D2 activity in human embryonic kidney-293 cells mediated by the phospholipase Cγ and protein kinase Cα signalling cascade

2000 ◽  
Vol 351 (3) ◽  
pp. 613-619 ◽  
Author(s):  
Rita SLAABY ◽  
Guangwei DU ◽  
Yelena M. ALTSHULLER ◽  
Michael A. FROHMAN ◽  
Klaus SEEDORF
Keyword(s):  
Protein Kinase ◽  
Cell Types ◽  
Dependent Manner ◽  
Human Embryonic Kidney ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Phospholipase D1

Phospholipase D (PLD)1 is quiescent in vitro and in vivo until stimulated by classical protein kinase C (PKC) isoforms, ADP-ribosylation factor or Rho family members. By contrast, PLD2 has high basal activity, and the mechanisms involved in agonist-induced activation of PLD2 are poorly understood. Using transiently transfected human embryonic kidney (HEK)-293 cells as a model system, we report in the present study that PLD2 overexpressed in HEK-293 cells exhibits regulatory properties similar to PLD1 when stimulated in response to insulin and phorbol ester. Co-expression of PLD1 or PLD2 with PKCα results in constitutive activation of both PLD isoforms, which cannot be further stimulated by insulin. Co-expression of PLD1 with phospholipase C (PLC)γ has the same effect, while co-expression of PLD2 with PLCγ allows PLD2 activity to be stimulated in an insulin-dependent manner. The PKC-specific inhibitors bisindolylmaleimide and Gö 6976 abolish insulin-induced PLD2 activation in HEK-293 cells co-expressing the insulin receptor, PLCγ and PLD2, confirming that not only PLD1, but PLD2 as well, is regulated in a PKC-dependent manner. Finally, we provide evidence that PKCα is constitutively associated with PLD2. In summary, we demonstrate that insulin treatment results in activation of both PLD1 and PLD2 in appropriate cell types when the appropriate upstream intermediate signalling components, i.e. PKCα and PLCγ, are expressed at sufficient levels.

In Vivo Induction and Delivery of Nerve Growth Factor, Using HEK-293 Cells

2004 ◽  
Vol 10 (9-10) ◽  
pp. 1492-1501 ◽  
Author(s):  
Michael P. McConnell ◽  
Sanjay Dhar ◽  
Sanjay Naran ◽  
Thang Nguyen ◽  
Ralph A. Bradshaw ◽  
...  
Keyword(s):  
Nerve Growth Factor ◽  
Growth Factor ◽  
Nerve Growth ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
In Vivo Induction

scholarly journals Specific targeting of the IL-23 receptor, using a novel small peptide noncompetitive antagonist, decreases the inflammatory response

2014 ◽  
Vol 307 (10) ◽  
pp. R1216-R1230 ◽  
Author(s):  
Christiane Quiniou ◽  
Maria Domínguez-Punaro ◽  
Frank Cloutier ◽  
Atefeh Erfani ◽  
Jamila Ennaciri ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Inflammatory Diseases ◽  
Jurkat Cells ◽  
Small Peptide ◽  
Proinflammatory Response ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells ◽  
Stat3 Phosphorylation

IL-23 is part of the IL-12 family of cytokines and is composed of the p19 subunit specific to IL-23 and the p40 subunit shared with IL-12. IL-23 specifically contributes to the inflammatory process of multiple chronic inflammatory autoimmune disorders, including psoriasis, multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis. So far, one antibody targeting the shared p40 subunit of IL-12 and IL-23, Ustekinumab, is approved clinically to treat psoriasis. However, there are no treatments inhibiting specifically the IL-23 proinflammatory response. We have developed small IL-23R-specific antagonists by designing all D-peptides arising from flexible regions of IL-23R. Of these peptides, we selected 2305 (teeeqqly), since in addition to its soluble properties, it inhibited IL-23-induced STAT3 phosphorylation in spleen cells. Peptide 2305 specifically binds to IL-23R/IL-12Rβ1-expressing HEK-293 cells and not to cells devoid of the receptor. Peptide 2305 showed functional selectivity by modulating IL-23-induced gene expression in IL-23R/IL-12Rβ1-expressing cells and in Jurkat cells; 2305 does not inhibit IL-12-induced cytokine expression in IL-12Rβ-IL-12Rβ2-HEK-293 cells. Finally, compared with anti-p40 treatment, 2305 effectively and selectively inhibits IL-23-induced inflammation in three in vivo mouse models: IL-23-induced ear inflammation, anti-CD40-induced systemic inflammatory response, and collagen-induced arthritis. We, hereby, describe the discovery and characterization of a potent IL-23R small-peptide modulator, 2305 (teeeqqly), that is effective in vivo. 2305 may be more convenient, less cumbersome, less costly, and most importantly, more specific than current biologics for the treatment of inflammatory conditions, and conceivably complement the actual therapies for these chronic and debilitating inflammatory diseases.

scholarly journals Protein kinase C-mediated Ca2+ entry in HEK 293 cells transiently expressing human TRPV4

2003 ◽  
Vol 140 (2) ◽  
pp. 413-421 ◽  
Author(s):  
Feng Xu ◽  
Eisaku Satoh ◽  
Toshihiko Iijima
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
Kinase C ◽  
293 Cells

scholarly journals In vitro and In vivo Activity of Novel Small-Molecule Inhibitors Targeting the Pleckstrin Homology Domain of Protein Kinase B/AKT

2009 ◽  
Vol 69 (12) ◽  
pp. 5073-5081 ◽  
Author(s):  
Sylvestor A. Moses ◽  
M. Ahad Ali ◽  
Song Zuohe ◽  
Lei Du-Cuny ◽  
Li Li Zhou ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Small Molecule ◽  
Small Molecule Inhibitors ◽  
Protein Kinase B ◽  
Pleckstrin Homology Domain ◽  
Pleckstrin Homology

scholarly journals Characterization of the reversible phosphorylation and activation of ERK8

2006 ◽  
Vol 394 (1) ◽  
pp. 365-373 ◽  
Author(s):  
Iva V. Klevernic ◽  
Margaret J. Stafford ◽  
Nicholas Morrice ◽  
Mark Peggie ◽  
Simon Morton ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Growth Factor ◽  
Protein Kinase ◽  
Insect Cells ◽  
Osmotic Shock ◽  
Tyrosine Phosphatase ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
293 Cells

ERK8 (extracellular-signal-regulated protein kinase 8) expressed in Escherichia coli or insect cells was catalytically active and phosphorylated at both residues of the Thr-Glu-Tyr motif. Dephosphorylation of the threonine residue by PP2A (protein serine/threonine phosphatase 2A) decreased ERK8 activity by over 95% in vitro, whereas complete dephosphorylation of the tyrosine residue by PTP1B (protein tyrosine phosphatase 1B) decreased activity by only 15–20%. Wild-type ERK8 expressed in HEK-293 cells was over 100-fold less active than the enzyme expressed in bacteria or insect cells, but activity could be increased by exposure to hydrogen peroxide, by incubation with the protein serine/threonine phosphatase inhibitor okadaic acid, or more weakly by osmotic shock. In unstimulated cells, ERK8 was monophosphorylated at Tyr-177, and exposure to hydrogen peroxide induced the appearance of ERK8 that was dually phosphorylated at both Thr-175 and Tyr-177. IGF-1 (insulin-like growth factor 1), EGF (epidermal growth factor), PMA or anisomycin had little effect on activity. In HEK-293 cells, phosphorylation of the Thr-Glu-Tyr motif of ERK8 was prevented by Ro 318220, a potent inhibitor of ERK8 in vitro. The catalytically inactive mutants ERK8[D154A] and ERK8[K42A] were not phosphorylated in HEK-293 cells or E. coli, whether or not the cells had been incubated with protein phosphatase inhibitors or exposed to hydrogen peroxide. Our results suggest that the activity of ERK8 in transfected HEK-293 cells depends on the relative rates of ERK8 autophosphorylation and dephosphorylation by one or more members of the PPP family of protein serine/threonine phosphatases. The major residue in myelin basic protein phosphorylated by ERK8 (Ser-126) was distinct from that phosphorylated by ERK2 (Thr-97), demonstrating that, although ERK8 is a proline-directed protein kinase, its specificity is distinct from ERK1/ERK2.

scholarly journals Nephroprotective activity of Annona Squamosa leaves against paracetamol-induced nephrotoxicity in rats: in vitro and in vivo experiments

2020 ◽  
Vol 6 (1) ◽  
Author(s):  
S. Neelima ◽  
P. Dwarakanadha Reddy ◽  
Chandra Sekhar Kothapalli Bannoth
Keyword(s):  
Kidney Tissue ◽  
Ethanolic Extract ◽  
Tissue Homogenate ◽  
Annona Squamosa ◽  
Hek 293 ◽  
Hek 293 Cells ◽  
In Vivo Experiments ◽  
293 Cells

Abstract Background Paracetamol (PCM), being extensively adapted analgesic and anti-inflammatory drug all over the world, beyond therapeutic dosages, the oxidative stress-involved nephrotoxicity has been evidenced. However, herbal plants are the windfall for the humankind providing solution for most of the wellness breakdowns. Annona squamosa (AS) is one of such plants with enormous therapeutic and nutraceutical potencies. The main aspiration of the current investigation is to evaluate the nephroprotective ability of ethanolic extract of Annona squamosa (EEAS) leaves against paracetamol-induced nephrotoxicity using in vitro human embryonic kidney (HEK)-293 cells and in vivo experiments in Wistar rats through biochemical parameters, oxidative parameters, and histopathological findings. Results When HEK-293 cells were incubated with PCM, an increased cell death associated with alterations in the morphology of normal cells was observed. At variable concentrations, HEK-293 cells co-treated with PCM and EEAS extracts gave a significant improvement in cell growth on comparing with PCM treatment showing cytoprotective feature of EEAS with an IC50 28.75 μg/mL. In vivo nephroprotective property was assessed from the amount of blood urea nitrogen (BUN) along with creatinine and uric acid which were reduced (P < 0.001) within serum and compact levels of glutathione, catalase, and superoxide dismutase which were termed as GSH, CAT, and SOD, respectively, were increased (P < 0.001) in kidney tissue homogenate in the treated groups than the PCM alone group. Results were additionally supported by histopathological observations. Conclusion The results exhibited that EEAS has impending benefits against PCM-induced nephrotoxicity through in vitro and in vivo experiments.

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