scholarly journals ShcA Mediates the Dominant Pathway to Extracellular Signal-Regulated Kinase Activation during Early Thymic Development

2006 ◽  
Vol 26 (23) ◽  
pp. 9035-9044 ◽  
Author(s):  
Paul Trampont ◽  
Li Zhang ◽  
Kodi S. Ravichandran
Keyword(s):  
Ex Vivo ◽  
Dominant Role ◽  
Cell Receptor ◽  
Thymocyte Development ◽  
Erk Activation ◽  
Thymic Development ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Phosphorylation ◽  
Extracellular Signal

ABSTRACT During thymic development, the β selection checkpoint is regulated by pre-T-cell receptor-initiated signals. Progression through this checkpoint is influenced by phosphorylation and activation of the serine/threonine kinases extracellular signal-regulated kinase 1 (ERK1) and ERK2, but the in vivo relevance of specific upstream players leading to ERK activation is not known. Here, using mice with a conditional loss of the shc1 gene or expressing mutants of ShcA, we demonstrate that the adapter protein ShcA is responsible for up to 70% of ERK activation in double-negative (DN) thymocytes in vivo and ex vivo. We also identify two specific tyrosines on ShcA that promote ERK phosphorylation in vivo, and mice expressing ShcA with mutations of these tyrosines show impaired DN thymocyte development. This work provides the first in vivo demonstration of the relative requirement of upstream adapters in controlling ERK activation during β selection and suggests a dominant role for ShcA.

scholarly journals Oxytocin antagonism prevents pregnancy-associated aortic dissection in a mouse model of Marfan syndrome

2019 ◽  
Vol 11 (490) ◽  
pp. eaat4822 ◽  
Author(s):  
Jennifer Pardo Habashi ◽  
Elena Gallo MacFarlane ◽  
Rustam Bagirzadeh ◽  
Caitlin Bowen ◽  
Nicholas Huso ◽  
...  
Keyword(s):  
Aortic Dissection ◽  
Mouse Model ◽  
Marfan Syndrome ◽  
Uterine Contraction ◽  
Aortic Wall ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Erk Kinase

Women with Marfan syndrome (MFS) are at high risk for pregnancy-associated aortic dissection. Pathogenic models that singularly invoke hemodynamic stress are difficult to reconcile with predominant postnatal occurrence of aortic tear, often occurring weeks to months after delivery. In consideration of events that peak at term, are sustained after delivery, and might synergize with previously defined signaling pathways implicated in aneurysm progression, we examined the hormone oxytocin, which initiates uterine contraction and milk letdown for the duration of lactation through phosphorylation of extracellular signal–regulated kinase (ERK). In a mouse model of MFS that shows highly penetrant postnatal aortic dissection, risk was strongly attenuated by preventing lactation or use of an oxytocin receptor antagonist. Survival correlated inversely with the extent of ERK activation in the aortic wall, and strong protection was observed upon attenuation of ERK phosphorylation using an inhibitor of ERK kinase (MEK) or the U.S. Food and Drug Administration–approved medication hydralazine, offering potential therapeutic strategies for pregnancy-associated vascular catastrophe in the setting of MFS.

scholarly journals Influence of ERK activation on decreased chemotaxis of mature human cord blood monocyte–derived dendritic cells to CCL19 and CXCL12

Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3173-3176 ◽  
Author(s):  
Geling Li ◽  
Sunanda Basu ◽  
Myung-Kwan Han ◽  
Young-June Kim ◽  
Hal E. Broxmeyer
Keyword(s):  
Dendritic Cells ◽  
Cord Blood ◽  
Human Cord Blood ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Graft Versus Host ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Insight Into ◽  
Dc Maturation

Abstract Dendritic cells (DCs) are important regulators in graft-versus-host disease (GVHD). To gain insight into cord blood (CB) DC immunology, we compared chemotactic responses of mature monocyte-derived DCs and maturation agent lipopolysaccharide (LPS)–induced signaling between CB and adult blood (AB). Mature CB DCs expressed reduced CCR7, but increased CXCR4. This was associated with reduced migratory efficiency toward both CCR7 ligand CCL19 and CXCR4 ligand CXCL12. LPS induced higher extracellular signal-regulated kinase (ERK) phosphorylation in CB than in AB DCs. Specific inhibition of ERK during CB DC maturation enhanced LPS-induced up-regulation of CCR7 and CXCR4 on CB DCs and their chemotaxis toward CCL19 and CXCL12, to a level similar to that of mature AB DCs. Overall, monocyte-derived CB DCs responded to LPS with stronger and sustained ERK activation, which negatively correlated with LPS-induced up-regulation of CCR7 and CXCR4 on CB DCs and their migratory responses. These findings may have potential relevance to better understanding DC function in CB transplantation.

scholarly journals Endogenous galectin-1 enforces class I–restricted TCR functional fate decisions in thymocytes

Blood ◽  
2008 ◽  
Vol 112 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Scot D. Liu ◽  
Chan C. Whiting ◽  
Tamar Tomassian ◽  
Mabel Pang ◽  
Stephanie J. Bissel ◽  
...  
Keyword(s):  
Positive Selection ◽  
Negative Selection ◽  
Partial Agonist ◽  
Cell Receptor ◽  
Intraepithelial Lymphocytes ◽  
Class I ◽  
Thymocyte Development ◽  
Erk Activation ◽  
Extracellular Signal ◽  
Erk Activity

Abstract During thymocyte development, the T-cell receptor (TCR) can discriminate major histocompatibility complex (MHC)/peptide ligands over a narrow range of affinities and translate subtle differences into functional fate decisions. How small differences in TCR input are translated into absolute differences in functional output is unclear. We examined the effects of galectin-1 ablation in the context of class-I–restricted thymocyte development. Galectin-1 expression opposed TCR partial agonist-driven positive selection, but promoted TCR agonist-driven negative selection of conventional CD8+ T cells. Galectin-1 expression also promoted TCR agonist-driven CD8αα intestinal intraepithelial lymphocytes (IEL) development. Recombinant galectin-1 enhanced TCR binding to agonist/MHC complexes and promoted a negative-selection-signaling signature, reflected in intensified rapid and transient extracellular signal-regulated kinase (ERK) activation. In contrast, galectin-1 expression antagonized ERK activity in thymocytes undergoing positive selection. We propose that galectin-1 aids in discriminating TCR-directed fate decisions by promoting TCR binding to agonist/MHC complexes and enforcing agonist-driven signals, while opposing partial-agonist signals. In this way, galectin-1 widens the distinction between TCR-directed functional fate cues.

scholarly journals The Extracellular Signal-regulated Kinase–Mitogen-activated Protein Kinase Pathway Phosphorylates and Targets Cdc25A for SCFβ-TrCP-dependent Degradation for Cell Cycle Arrest

2009 ◽  
Vol 20 (8) ◽  
pp. 2186-2195 ◽  
Author(s):  
Michitaka Isoda ◽  
Yoshinori Kanemori ◽  
Nobushige Nakajo ◽  
Sanae Uchida ◽  
Katsumi Yamashita ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Genotoxic Stress ◽  
Mitogen Activated Protein Kinase ◽  
Erk Pathway ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Cycle Arrest ◽  
Erk Phosphorylation ◽  
Extracellular Signal

The extracellular signal-regulated kinase (ERK) pathway is generally mitogenic, but, upon strong activation, it causes cell cycle arrest by a not-yet fully understood mechanism. In response to genotoxic stress, Chk1 hyperphosphorylates Cdc25A, a positive cell cycle regulator, and targets it for Skp1/Cullin1/F-box protein (SCF)β-TrCP ubiquitin ligase-dependent degradation, thereby leading to cell cycle arrest. Here, we show that strong ERK activation can also phosphorylate and target Cdc25A for SCFβ-TrCP-dependent degradation. When strongly activated in Xenopus eggs, the ERK pathway induces prominent phosphorylation and SCFβ-TrCP-dependent degradation of Cdc25A. p90rsk, the kinase downstream of ERK, directly phosphorylates Cdc25A on multiple sites, which, interestingly, overlap with Chk1 phosphorylation sites. Furthermore, ERK itself phosphorylates Cdc25A on multiple sites, a major site of which apparently is phosphorylated by cyclin-dependent kinase (Cdk) in Chk1-induced degradation. p90rsk phosphorylation and ERK phosphorylation contribute, roughly equally and additively, to the degradation of Cdc25A, and such Cdc25A degradation occurs during oocyte maturation in which the endogenous ERK pathway is fully activated. Finally, and importantly, ERK-induced Cdc25A degradation can elicit cell cycle arrest in early embryos. These results suggest that strong ERK activation can target Cdc25A for degradation in a manner similar to, but independent of, Chk1 for cell cycle arrest.

scholarly journals Intercellular propagation of extracellular signal-regulated kinase activation revealed by in vivo imaging of mouse skin

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Toru Hiratsuka ◽  
Yoshihisa Fujita ◽  
Honda Naoki ◽  
Kazuhiro Aoki ◽  
Yuji Kamioka ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Mouse Skin ◽  
Egf Receptors ◽  
M Cell ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Erk Activity

Extracellular signal-regulated kinase (ERK) is a key effector of many growth signalling pathways. In this study, we visualise epidermal ERK activity in living mice using an ERK FRET biosensor. Under steady-state conditions, the epidermis occasionally revealed bursts of ERK activation patterns where ERK activity radially propagated from cell to cell. The frequency of this spatial propagation of radial ERK activity distribution (SPREAD) correlated with the rate of epidermal cell division. SPREADs and proliferation were stimulated by 12-O-tetradecanoylphorbol 13-acetate (TPA) in a manner dependent on EGF receptors and their cognate ligands. At the wounded skin, ERK activation propagated as trigger wave in parallel to the wound edge, suggesting that ERK activation propagation can be superimposed. Furthermore, by visualising the cell cycle, we found that SPREADs were associated with G2/M cell cycle progression. Our results provide new insights into how cell proliferation and transient ERK activity are synchronised in a living tissue.

Ribosomal S6 kinase-1 modulates interleukin-1β-induced persistent activation of NF-κB through phosphorylation of IκBβ

2006 ◽  
Vol 291 (6) ◽  
pp. C1336-C1345 ◽  
Author(s):  
Shanqin Xu ◽  
Hossein Bayat ◽  
Xiuyun Hou ◽  
Bingbing Jiang
Keyword(s):  
Nuclear Translocation ◽  
Erk Signaling ◽  
Signaling Cascade ◽  
S6 Kinase ◽  
Small Interference Rna ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Ribosomal S6 Kinase

Activation of NF-κB requires the phosphorylation and degradation of its associated inhibitory proteins, IκB. Previously, we reported that the extracellular signal-regulated kinase (ERK) is required for IL-1β to induce persistent activation of NF-κB in cultured rat vascular smooth muscle cells (VSMCs). The present study examined the mechanism by which the ERK signaling cascade modulates the duration of NF-κB activation. In cultured rat VSMCs, IL-1β activated ERK and induced degradation of both IκBα and IκBβ, which was associated with nuclear translocation of both ribosomal S6 kinase (RSK)1 and NF-κB p65. RSK1, a downstream kinase of ERK, was associated with an IκBβ/NF-κB complex, which was independent of the phosphorylation status of RSK1. Treatment of VSMCs with IL-1β decreased IκBβ in the RSK1/IκBβ/NF-κB complex, an effect that was attenuated by inhibition of ERK activation. Knockdown of RSK1 by small interference RNA attenuated the IL-1β-induced IκBβ decrease without influencing ether ERK phosphorylation or the earlier IκBα degradation. By using recombinant wild-type and mutant IκBβ proteins, both active ERK2 and RSK1 were found to directly phosphorylate IκBβ, but only active RSK1 phosphorylated IκBβ on Ser19 and Ser23, two sites known to mediate the subsequent ubiquitination and degradation. In conclusion, in the ERK signaling cascade, RSK1 is a key component that directly phosphorylates IκBβ and contributes to the persistent activation of NF-κB by IL-1β.

scholarly journals Extracellular Signal–Regulated Kinase (Erk) Activation by the Pre-T Cell Receptor in Developing Thymocytes in Vivo

1999 ◽  
Vol 190 (11) ◽  
pp. 1647-1656 ◽  
Author(s):  
Alison M. Michie ◽  
Sébastien Trop ◽  
David L. Wiest ◽  
Juan Carlos Zúñiga-Pflücker
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Experimental System ◽  
Cell Receptor ◽  
Tcr Signaling ◽  
Erk Activation ◽  
Downstream Signaling ◽  
Extracellular Signal ◽  
Signaling Components

The first checkpoint in T cell development occurs between the CD4−CD8− and CD4+CD8+ stages and is associated with formation of the pre-T cell receptor (TCR). The signaling mechanisms that drive this progression remain largely unknown. Here, we show that extracellular signal–regulated kinases (ERKs)-1/2 are activated upon engagement of the pre-TCR. Using a novel experimental system, we demonstrate that expression of the pre-TCR by developing thymocytes induces ERK-1/2 activation within the thymus. In addition, the activation of this pre-TCR signaling cascade is mediated through Lck. These findings directly link pre-TCR complex formation with specific downstream signaling components in vivo.

scholarly journals Gonadotropin-Releasing Hormone Pulse Frequency-Dependent Activation of Extracellular Signal-Regulated Kinase Pathways in Perifused LβT2 Cells

Endocrinology ◽  
2005 ◽  
Vol 146 (12) ◽  
pp. 5503-5513 ◽  
Author(s):  
Haruhiko Kanasaki ◽  
Gregoy Y. Bedecarrats ◽  
Kyung-Yoon Kam ◽  
Shuyun Xu ◽  
Ursula B. Kaiser
Keyword(s):  
Pulse Frequency ◽  
Frequency Dependent ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Gnrh Release ◽  
The Difference ◽  
Stimulation Of

The pattern of GnRH release is associated with differential synthesis and release of LH and FSH. Using a perifusion system, we previously reported that stimulation of the LβT2 cell line with varying GnRH pulse frequencies resulted in differential stimulation of LHβ and FSHβ gene transcription, analogous to previous observations in primary gonadotropes. In the present study, we investigated the patterns of MAPK activation by GnRH and the role of MAPK in mediating the frequency-dependent effects. In static culture, ERK activation in LβT2 cells stimulated with continuous GnRH (10 nm) was maximal by 10 min and persisted for up to 6 h, with a return to basal levels by 20 h. In contrast, stimulation with continuous GnRH (10 nm) in perifused cells resulted in a more sustained activation of ERK. To investigate the effects of GnRH pulse frequency on ERK activation, perifused LβT2 cells were stimulated with pulsatile GnRH at a frequency of one pulse every 30 min or one pulse every 2 h for 20 h (10 nm, 5 min/pulse). After the final GnRH pulse, cells were lysed at frequent intervals and levels of ERK phosphorylation were measured. Under high-frequency conditions, ERK activation was maximal 10 min after the GnRH pulse and returned to baseline levels by 20 min. In contrast, under lower GnRH pulse frequency conditions, ERK activation occurred more rapidly and activation was more sustained, with a slower rate of ERK dephosphorylation. These changes resulted in different levels of nuclear phosphorylated ERK. Blockade of ERK activation abolished GnRH-dependent activation of LHβ and FSHβ transcription at both high and low pulse frequencies. These results demonstrate that in perifused LβT2 cells, distinct patterns of ERK activation/inactivation are regulated by GnRH pulse frequency, and the difference in ERK activation may be important for GnRH pulse frequency-dependent differential stimulation of LHβ and FSHβ gene expression.

scholarly journals Autocrine Extracellular Signal-regulated Kinase (ERK) Activation in Normal Human Keratinocytes: Metalloproteinase-mediated Release of Amphiregulin Triggers Signaling from ErbB1 to ERK

2004 ◽  
Vol 15 (9) ◽  
pp. 4299-4309 ◽  
Author(s):  
Sanjay Kansra ◽  
Stefan W. Stoll ◽  
Jessica L. Johnson ◽  
James T. Elder
Keyword(s):  
Growth Factor ◽  
Neutralizing Antibodies ◽  
Human Keratinocytes ◽  
Erk Activation ◽  
Extracellular Signal Regulated Kinase ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Normal Human Keratinocytes ◽  
Metalloproteinase Inhibitors ◽  
Normal Human

ErbB signaling through extracellular signal-regulated kinase (ERK) has been implicated in regulating the expression of ErbB ligands in hyperproliferative skin disorders and wound healing. Here, we characterize the process of autocrine ERK activation in cultured normal human keratinocytes (NHKs) subjected to growth factor (GF) deprivation. Basal ERK phosphorylation was lower after 48 h than after 24 h of GF deprivation, and lowest at 30–60 min after an additional medium change. ERK phosphorylation was markedly increased by low concentrations of epidermal growth factor (EGF) (0.2–1 ng/ml) that provoked only a limited increase in ErbB1 tyrosine phosphorylation and internalization. Basal ErbB tyrosine phosphorylation and ERK phosphorylation were inhibited by two different ErbB receptor tyrosine kinase inhibitors, by the ErbB1-specific neutralizing monoclonal antibody 225 IgG, by two different metalloproteinase inhibitors, and by neutralizing antibodies against amphiregulin (AR). In contrast, these responses were unaffected by neutralizing antibodies against other ErbB1 ligands or the ErbB2 inhibitors geldanamycin and AG825. The time course of autocrine ERK phosphorylation correlated with the appearance of soluble AR, and two different metalloproteinase inhibitors blocked AR release. These results define an amphiregulin- and ErbB1-dependent mechanism by which autocrine ERK activation is maintained in NHKs, even when ErbB1 autophosphorylation and internalization are limited.

scholarly journals Single-cell RNA sequencing reveals ex vivo signatures of SARS-CoV-2-reactive T cells through ‘reverse phenotyping’

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
David S. Fischer ◽  
Meshal Ansari ◽  
Karolin I. Wagner ◽  
Sebastian Jarosch ◽  
Yiqi Huang ◽  
...  
Keyword(s):  
T Cells ◽  
Single Cell ◽  
Rna Sequencing ◽  
Ex Vivo ◽  
Severe Disease ◽  
Human Leukocyte ◽  
Cell Receptor ◽  
Single Cell Rna Sequencing

AbstractThe in vivo phenotypic profile of T cells reactive to severe acute respiratory syndrome (SARS)-CoV-2 antigens remains poorly understood. Conventional methods to detect antigen-reactive T cells require in vitro antigenic re-stimulation or highly individualized peptide-human leukocyte antigen (pHLA) multimers. Here, we use single-cell RNA sequencing to identify and profile SARS-CoV-2-reactive T cells from Coronavirus Disease 2019 (COVID-19) patients. To do so, we induce transcriptional shifts by antigenic stimulation in vitro and take advantage of natural T cell receptor (TCR) sequences of clonally expanded T cells as barcodes for ‘reverse phenotyping’. This allows identification of SARS-CoV-2-reactive TCRs and reveals phenotypic effects introduced by antigen-specific stimulation. We characterize transcriptional signatures of currently and previously activated SARS-CoV-2-reactive T cells, and show correspondence with phenotypes of T cells from the respiratory tract of patients with severe disease in the presence or absence of virus in independent cohorts. Reverse phenotyping is a powerful tool to provide an integrated insight into cellular states of SARS-CoV-2-reactive T cells across tissues and activation states.

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