scholarly journals Regulation of ERK phosphorylation in differentiated arterial muscle of rabbits

2001 ◽  
Vol 281 (1) ◽  
pp. H114-H123 ◽  
Author(s):  
Paul H. Ratz
Keyword(s):  
Adrenergic Receptor ◽  
Map Kinases ◽  
Mek Inhibitor ◽  
Erk Activation ◽  
Differentiated Cells ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Isolated Arteries

Extracellular signal-regulated kinases (ERK) and mitogen-activated protein (MAP) kinases participate in cell signaling, regulating cell growth. In differentiated cells, the role ERK plays is less well known. This study quantified the degree of basal and stimulated ERK phosphorylation and contraction in freshly isolated arteries. The level of basal ERK phosphorylation was identical in preloaded and slack arteries, was greater in media than in the whole artery, and was reduced by the MAP or ERK kinase (MEK) inhibitor PD-98059. Chemical denudation using 1 H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one did not elevate basal ERK phosphorylation. PD-98059 reduced maximum phenylephrine (PE)-stimulated ERK phosphorylation but not force. Pervanadate elevated ERK phosphorylation without causing contraction. Contractions produced by PE and relaxations produced by PE washout preceded the ERK phosphorylation. K+ depolarization, muscle stretch, and angiotensin II elevated ERK phosphorylation transiently, whereas PE maintained ERK phosphorylation for 30 min. The α1A-adrenergic receptor antagonist WB-4101 reduced PE-stimulated force by 70% and abolished PE-induced ERK phosphorylation. Afterloaded and zero-load contractions produced by K+ depolarization displayed identical increases in ERK phosphorylation. These data indicate that ERK was active basally in the differentiated artery but regulated by the endothelium and that ERK phosphorylation was not load dependent. A strong correlation between PE-induced force and ERK phosphorylation supports the hypothesis that ERK activation may reflect a signal “notifying” the cell of the degree of α1-adrenergic receptor-induced contraction.

Regulation of polymorphonuclear leukocyte phagocytosis by myosin light chain kinase after activation of mitogen-activated protein kinase

Blood ◽  
2000 ◽  
Vol 95 (7) ◽  
pp. 2407-2412 ◽  
Author(s):  
Pamela J. Mansfield ◽  
James A. Shayman ◽  
Laurence A. Boxer
Keyword(s):  
Map Kinase ◽  
Light Chain ◽  
Polymorphonuclear Leukocyte ◽  
Myosin Light Chain Kinase ◽  
Myosin Light Chain ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
Erk Activation ◽  
Extracellular Signal ◽  
Mitogen Activated Protein

Abstract Polymorphonuclear leukocyte (PMNL) phagocytosis mediated by FcγRII proceeds in concert with activation of the mitogen-activated protein (MAP) kinase, extracellular signal-regulated kinase ERK2. We hypothesized that myosin light chain kinase (MLCK) could be phosphorylated and activated by ERK, thereby linking the MAP kinase pathway to the activation of cytoskeletal components required for pseudopod formation. To explore this potential linkage, PMNLs were challenged with antibody-coated erythrocytes (EIgG). Peak MLCK activity, 3-fold increased over controls, occurred at 4 to 6 minutes, corresponding with the peak rate of target ingestion and ERK2 activity. The MLCK inhibitor ML-7 (10 μmol/L) inhibited both phagocytosis and MLCK activity to basal values, thereby providing further support for the linkage between the functional response and the requirement for MLCK activation. The MAPK kinase (MEK) inhibitor PD098059 inhibited phagocytosis, MLCK activity, and ERK2 activity by 80% to 90%. To directly link ERK activation to MLCK activation, ERK2 was immunoprecipitated from PMNLs after EIgG ingestion. The isolated ERK2 was incubated with PMNL cytosol as a source of unactivated MLCK and with MLCK substrate; under these conditions ERK2 activated MLCK, resulting in phosphorylation of the MLCK substrate or of the myosin light chain itself. Because MLCK activates myosin, we evaluated the effect of directly inhibiting myosin adenosine triphosphatase using 2,3-butanedione monoxime (BDM) and found that phagocytosis was inhibited by more than 90% but MLCK activity remained unaffected. These results are consistent with the interpretation that MEK activates ERK, ERK2 then activates MLCK, and MLCK activates myosin. MLCK activation is a critical step in the cytoskeletal changes resulting in pseudopod formation.

scholarly journals A Novel Regulatory Mechanism of Map Kinases Activation and Nuclear Translocation Mediated by Pka and the Ptp-Sl Tyrosine Phosphatase

1999 ◽  
Vol 147 (6) ◽  
pp. 1129-1136 ◽  
Author(s):  
Carmen Blanco-Aparicio ◽  
Josema Torres ◽  
Rafael Pulido
Keyword(s):  
Map Kinases ◽  
Nuclear Translocation ◽  
Tyrosine Phosphatase ◽  
Phosphorylation Site ◽  
Extracellular Signal Regulated Kinase ◽  
Inactive Form ◽  
Extracellular Signal ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Dependent Protein

Protein tyrosine phosphatase PTP-SL retains mitogen-activated protein (MAP) kinases in the cytoplasm in an inactive form by association through a kinase interaction motif (KIM) and tyrosine dephosphorylation. The related tyrosine phosphatases PTP-SL and STEP were phosphorylated by the cAMP-dependent protein kinase A (PKA). The PKA phosphorylation site on PTP-SL was identified as the Ser231 residue, located within the KIM. Upon phosphorylation of Ser231, PTP-SL binding and tyrosine dephosphorylation of the MAP kinases extracellular signal–regulated kinase (ERK)1/2 and p38α were impaired. Furthermore, treatment of COS-7 cells with PKA activators, or overexpression of the Cα catalytic subunit of PKA, inhibited the cytoplasmic retention of ERK2 and p38α by wild-type PTP-SL, but not by a PTP-SL S231A mutant. These findings support the existence of a novel mechanism by which PKA may regulate the activation and translocation to the nucleus of MAP kinases.

Phosphatidylinositol 3-kinases regulate ERK and p38 MAP kinases in canine colonic smooth muscle

2000 ◽  
Vol 279 (2) ◽  
pp. C352-C360 ◽  
Author(s):  
Ilia A. Yamboliev ◽  
Kevin M. Wiesmann ◽  
Cherie A. Singer ◽  
Jason C. Hedges ◽  
William T. Gerthoffer
Keyword(s):  
Protein Kinase ◽  
Map Kinase ◽  
Map Kinases ◽  
Calf Serum ◽  
Specific Effect ◽  
Kinase C ◽  
Extracellular Signal ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Intact Muscle

In canine colon, M2/M3 muscarinic receptors are coupled to extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases. We tested the hypothesis that this coupling is mediated by enzymes of the phosphatidylinositol (PI) 3-kinase family. RT-PCR and Western blotting demonstrated expression of two isoforms, PI 3-kinase-α and PI 3-kinase-γ. Muscarinic stimulation of intact muscle strips (10 μM ACh) activated PI 3-kinase-γ, ERK and p38 MAP kinases, and MAP kinase-activated protein kinase-2, whereas PI 3-kinase-α activation was not detected. Wortmannin (25 μM) abolished the activation of PI 3-kinase-γ, ERK, and p38 MAP kinases. MAP kinase inhibition was a PI 3-kinase-γ-specific effect, since wortmannin did not inhibit recombinant activated murine ERK2 MAP kinase, protein kinase C, Raf-1, or MAP kinase kinase. In cultured muscle cells, newborn calf serum (3%) activated PI 3-kinase-α and PI 3-kinase-γ isoforms, ERK and p38 MAP kinases, and stimulated chemotactic cell migration. Using wortmannin and LY-294002 to inhibit PI 3-kinase activity and PD-098059 and SB-203580 to inhibit ERK and p38 MAP kinases, we established that these enzymes are functionally important for regulation of chemotactic migration of colonic myocytes.

scholarly journals Analysis of Mitogen-Activated Protein Kinases in Bone and Cartilage of Patients with Rheumatoid Arthritis Treated with Abatacept

2016 ◽  
Vol 9 ◽  
pp. CMAMD.S34424 ◽  
Author(s):  
Katsuaki Kanbe ◽  
Koei Oh ◽  
Junji Chiba ◽  
Yasuo Inoue ◽  
Masashi Taguchi ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Map Kinases ◽  
Histological Changes ◽  
Extracellular Signal ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Hematoxylin And Eosin ◽  
Factor Α ◽  
Necrosis Factor ◽  
And Cartilage

The aim of this study was to analyze the histological changes related to mitogen-activated protein (MAP) kinases in bone and cartilage treated with abatacept for rheumatoid arthritis (RA). A total of 20 patients of bone and cartilage were assessed: 10 abatacept with methotrexate (MTX)-treated RA patients were compared with 10 MTX-treated RA patients (control). The histology of bone and cartilage was observed by staining with hematoxylin and eosin and analyzed immunohistochemically for the expression of tumor necrosis factor-α, interleukin-6, CD4 (T cell), CD68 (macrophage), receptor activator of nuclear kappa-B ligand, osteoprotegerin, osteopontin, CD29 (β-1 integrin), phospho-p38 MAPK (Tyr180/Tyr182), phospho-p44/42 MAPK (extracellular signal-regulated kinase, ERK1/ERK2), and phosphor-c-Jun N-terminal kinase. The expressions of CD29 known as mechanoreceptor and ERK known as mechanotransduction signal protein in MAP kinases in the bone and cartilage of patients treated with abatacept were significantly different from those of control. These findings suggest that increases in CD29 and ERK in MAP kinases may change the metabolism of bone and cartilage in RA patients treated with abatacept.

scholarly journals The Arf GAP AGAP2 interacts with β-arrestin2 and regulates β2-adrenergic receptor recycling and ERK activation

2013 ◽  
Vol 452 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Yuanjun Wu ◽  
Yu Zhao ◽  
Xiaojie Ma ◽  
Yunjuan Zhu ◽  
Jaimin Patel ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Receptor Activation ◽  
Recycling Endosomes ◽  
Erk Activation ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Β2 Adrenergic Receptor ◽  
Adp Ribosylation Factor

AGAP2 [Arf (ADP-ribosylation factor) GAP (GTPase-activating protein) with GTP-binding-protein-like, ankyrin repeat and PH (pleckstrin homology) domains] is a multidomain Arf GAP that was shown to promote the fast recycling of transferrin receptors. In the present study we tested the hypothesis that AGAP2 regulates the trafficking of β2-adrenergic receptors. We found that AGAP2 formed a complex with β-arrestin1 and β-arrestin2, proteins that are known to regulate β2-adrenergic receptor signalling and trafficking. AGAP2 co-localized with β-arrestin2 on the plasma membrane, and knockdown of AGAP2 expression reduced plasma membrane association of β-arrestin2 upon β2-adrenergic receptor activation. AGAP2 also co-localized with internalized β2-adrenergic receptors on endosomes, and overexpression of AGAP2 slowed accumulation of β2-adrenergic receptor in the perinuclear recycling endosomes. In contrast, knockdown of AGAP2 expression prevented the recycling of the β2-adrenergic receptor back to the plasma membrane. In addition, AGAP2 formed a complex with endogenous ERK (extracellular-signal-regulated kinase) and overexpression of AGAP2 potentiated ERK phosphorylation induced by β2-adrenergic receptors. Taken together, these results support the hypothesis that AGAP2 plays a role in the signalling and recycling of β2-adrenergic receptors.

scholarly journals The Tumor Suppressor p53 Inhibits Net, an Effector of Ras/Extracellular Signal-Regulated Kinase Signaling

2004 ◽  
Vol 24 (3) ◽  
pp. 1132-1142 ◽  
Author(s):  
Koji Nakade ◽  
Hong Zheng ◽  
Gitali Ganguli ◽  
Gilles Buchwalter ◽  
Christian Gross ◽  
...  
Keyword(s):  
Gene Expression ◽  
Tumor Suppressor ◽  
Map Kinases ◽  
Specific Gene ◽  
Tumor Suppressor P53 ◽  
Extracellular Signal ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway

ABSTRACT The tumor suppressor function of p53 is linked to its ability to repress gene expression, but the mechanisms of specific gene repression are poorly understood. We report that wild-type p53 inhibits an effector of the Ras oncogene/mitogen-activated protein (MAP) kinase pathway, the transcription factor Net. Tumor-associated mutant p53s are less efficient inhibitors. p53 inhibits by preventing phosphorylation of Net by MAP kinases. Loss of p53 in vivo leads to increased Net phosphorylation in response to wound healing and UV irradiation of skin. Our results show that p53 can repress specific gene expression by inhibiting Net, a factor implicated in cell cycle entry.

scholarly journals Transactivation of Fra-1 and Consequent Activation of AP-1 Occur Extracellular Signal-Regulated Kinase Dependently

2002 ◽  
Vol 22 (2) ◽  
pp. 587-598 ◽  
Author(s):  
Matthew R. Young ◽  
Rajalakshmi Nair ◽  
Natalie Bucheimer ◽  
Preety Tulsian ◽  
Nicole Brown ◽  
...  
Keyword(s):  
Map Kinases ◽  
Phosphorylation Site ◽  
Activator Protein 1 ◽  
Transactivation Domain ◽  
Resistant Variant ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Shift Analysis ◽  
Expression Construct ◽  
Mitogen Activated Protein

ABSTRACT Mitogen-activated protein (MAP) kinase, extracellular-signal-regulated kinases (ERKs) play an important role in activating AP-1-dependent transcription. Studies using the JB6 mouse epidermal model and a transgenic mouse model have established a requirement for AP-1-dependent transcription in tumor promotion. Tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor induce activator protein 1 (AP-1) activity and neoplastic transformation in JB6 transformation-sensitive (P+) cells, but not in transformation-resistant (P−) variants. The resistance in one of the P− variants can be attributed to the low levels of the MAP kinases, ERKs 1 and 2, and consequent nonresponsiveness to AP-1 activation. The resistant variant is not deficient in c-fos transcription. The purpose of these studies was to define the targets of activated ERK that lead to AP-1 transactivation. The results establish that the transactivation domain of Fra-1 can be activated, that activation of Fra-1 is ERK dependent, and that a putative ERK phosphorylation site must be intact for activation to occur. Fra-1 was activated by TPA in ERK-sufficient P+ cells but not in ERK-deficient P− cells. A similar activation pattern was seen for c-Fos but not for Fra-2. Gel shift analysis identified Fra-1 as distinguishing mitogen-activated (P+) from nonactivated (P−) AP-1 complexes. A second AP-1-nonresponsive P− variant that underexpresses Fra-1 gained AP-1 response upon introduction of a Fra-1 expression construct. These observations suggest that ERK-dependent activation of Fra-1 is required for AP-1 transactivation in JB6 cells.

ERK activation by urea in the renal inner medullary mIMCD3 cell line

1999 ◽  
Vol 277 (2) ◽  
pp. F176-F185 ◽  
Author(s):  
Xiao-Yan Yang ◽  
Zheng Zhang ◽  
David M. Cohen
Keyword(s):  
Mdck Cells ◽  
Collecting Duct ◽  
Mek Inhibitor ◽  
Erk Activation ◽  
Hypertonic Stress ◽  
Erk Phosphorylation ◽  
Extracellular Signal ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Renal Inner Medulla

Urea- and NaCl-inducible extracellular signal-regulated kinase (ERK) phosphorylation exhibited dissimilar kinetics. Among cell lines examined, the effect of urea was unique to mIMCD3 inner medullary collecting duct cells and MDCK cells. Urea-inducible ERK activation was ∼10-fold less sensitive to the MEK inhibitor, PD-98059, than was that of NaCl. This difference did not appear to be accounted for by differential activation of MEK isoforms. Interestingly, the inhibitor of p38 activation, SB-203580, abrogated the effect of both urea and NaCl upon both ERK and MEK activation; however, the former was much less sensitive to the inhibitor. Consistent with this observation, NaCl was much more effective than urea at inducing p38 phosphorylation. The effect of hypertonic stress (e.g., sorbitol 100 mM) could be blocked by appropriate medium dilution such that isotonicity was maintained. In marked contrast, the effect of hyperosmotic urea could not be blocked in this fashion, implying the absence of dependence upon cell volume. Together, these data suggest that cells of the renal inner medulla are potentially uniquely responsive to urea and that urea and hypertonic stressors induce ERK activation through distinct mechanisms.

scholarly journals Urea activates ribosomal S6 kinase (RSK) in a MEK-dependent fashion in renal mIMCD3 cells

1998 ◽  
Vol 274 (1) ◽  
pp. F73-F78 ◽  
Author(s):  
Zheng Zhang ◽  
David M. Cohen
Keyword(s):  
Nuclear Translocation ◽  
Collecting Duct ◽  
Renal Medulla ◽  
Mek Inhibitor ◽  
Mitogen Activated Protein Kinase ◽  
S6 Kinase ◽  
Erk Activation ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Ribosomal S6 Kinase

Urea activates a characteristic subset of signaling pathways in a tissue-specific fashion, including transcription of immediate early genes through activation of the mitogen-activated protein kinase (MAPK), ERK (extracellular signal-regulated kinase), and activation of its transcription factor substrate, Elk-1. The ability of urea to activate the ERK effector and pivotal regulatory kinase, ribosomal S6 kinase (RSK), was investigated in mIMCD3 renal inner medullary collecting duct cells. Urea upregulated RSK activity in a time-dependent fashion in serum-deprived mIMCD3 cells; the effect was maximal at 5 min. Activation by hypertonic NaCl, in contrast, was negligible at 5 min and peaked at 15 min. Both stimuli induced the nuclear translocation of cytosolic RSK, as determined via immunofluorescence. Importantly, activation of RSK by both solutes was MAPK/ERK kinase (MEK) dependent, as determined by the ability of the specific MEK inhibitor, PD-98059, to abrogate the response. Taken together, these data indicate that urea activates the ERK effector, RSK, in cells of the renal medulla in an ERK-dependent fashion, further emphasizing the functional significance of urea signaling through ERK activation in renal medullary cells.

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