scholarly journals Differential Activation of Mitogen-Activated Protein Kinases in Experimental Mesangioproliferative Glomerulonephritis

2000 ◽  
Vol 11 (2) ◽  
pp. 232-240
Author(s):  
DIRK BOKEMEYER ◽  
TAMMO OSTENDORF ◽  
UTA KUNTER ◽  
MARION LINDEMANN ◽  
HERBERT J. KRAMER ◽  
...  
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
Cellular Proliferation ◽  
Kinase Activity ◽  
P38 Map Kinase ◽  
Cellular Growth ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Maximal Increase

Abstract. Multiple extracellular mitogens are involved in the pathogenesis of proliferative forms of glomerulonephritis (GN). In vitro studies demonstrate the pivotal role of mitogenactivated protein (MAP) kinases in the regulation of cellular proliferation. This study was conducted to examine whether these kinases, as a convergence point of mitogenic stimuli, are activated in mesangioproliferative GN in vivo. Therefore, anti-Thy1 GN was induced in rats using a monoclonal anti-Thy1.1 antibody (OX-7). Whole cortical tissue as well as isolated glomeruli were examined at different time points using kinase activity assays and Western blot analysis. A maximal increase in the number of glomerular mitotic figures (9.7-fold) was demonstrated 6 d after injection of the anti-Thy1.1 antibody. In parallel with this finding, a significant increase in cortical, and more dramatically glomerular, activity of extracellular signal-regulated kinase (ERK) was detected. Maximal activation of ERK was detectable on day 6. This activation of ERK was accompanied by an increase in the expression of MEK (MAP kinase/ERK kinase), the ERK-activating kinase. A marked induction of glomerular apoptosis at 2 h after injection of the anti-Thy1.1 antibody, which subsided subsequently, was demonstrated using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay as well as staining for single-stranded DNA. However, no significant activation of stress-activated protein kinase or p38 MAP kinase, both MAP kinases that are suggested to induce apoptosis and to inhibit cellular growth, was detectable at this early time point. Rather, on day 6 a dramatic decrease in the activity of p38 MAP kinase, which might have contributed to the overshooting glomerular cellular proliferation, was observed. Treatment of rats with heparin blunted glomerular proliferation as well as ERK activation and restored p38 MAP kinase activity. These observations point to ERK and p38 MAP kinase as putative mediators of the proliferative response in mesangioproliferative GN and suggest that upregulation of MEK is involved in the long-term regulation of ERK in vivo.

Evidence for modulation of smooth muscle force by the p38 MAP kinase/HSP27 pathway

2000 ◽  
Vol 278 (6) ◽  
pp. H1899-H1907 ◽  
Author(s):  
Ilia A. Yamboliev ◽  
Jason C. Hedges ◽  
Jack L.-M. Mutnick ◽  
Leonard P. Adam ◽  
William T. Gerthoffer
Keyword(s):  
Smooth Muscle ◽  
Muscle Contraction ◽  
Map Kinase ◽  
Map Kinases ◽  
Contractile Response ◽  
P38 Map Kinase ◽  
Hsp27 Phosphorylation ◽  
Sb 203580

Mitogen-activated protein (MAP) kinases signal to proteins that could modify smooth muscle contraction. Caldesmon is a substrate for extracellular signal-related kinases (ERK) and p38 MAP kinases in vitro and has been suggested to modulate actin-myosin interaction and contraction. Heat shock protein 27 (HSP27) is downstream of p38 MAP kinases presumably participating in the sustained phase of muscle contraction. We tested the role of caldesmon and HSP27 phosphorylation in the contractile response of vascular smooth muscle by using inhibitors of both MAP kinase pathways. In intact smooth muscle, PD-098059 abolished endothelin-1 (ET-1)-stimulated phosphorylation of ERK MAP kinases and caldesmon, but p38 MAP kinase activation and contractile response remained unaffected. SB-203580 reduced muscle contraction and inhibited p38 MAP kinase and HSP27 phosphorylation but had no effect on ERK MAP kinase and caldesmon phosphorylation. In permeabilized muscle fibers, SB-203580 and a polyclonal anti-HSP27 antibody attenuated ET-1-dependent contraction, whereas PD-098059 had no effect. These results suggest that ERK MAP kinases phosphorylate caldesmon in vivo but that activation of this pathway is unnecessary for force development. The generation of maximal force may be modulated by the p38 MAP kinase/HSP27 pathway.

In vitro and in vivo regulation of hepatic mitogen-activated protein kinases in fetal rats

1994 ◽  
Vol 267 (6) ◽  
pp. G1078-G1086 ◽  
Author(s):  
J. M. Boylan ◽  
P. A. Gruppuso
Keyword(s):  
Growth Factor ◽  
Map Kinase ◽  
Map Kinases ◽  
Kinase Activity ◽  
Fetal Hepatocytes ◽  
Mitogen Activated Protein ◽  
Fetal Hepatocyte ◽  
Hepatocyte Growth

We have studied the role of mitogen-activated protein (MAP) kinases in fetal hepatocyte growth in vitro and in vivo. With myelin basic protein (MBP) as the phosphate acceptor, kinase activity in cultured fetal hepatocyte lysates increased fourfold after exposure to transforming growth factor-alpha (TGF-alpha) for 10 min. This TGF-alpha-responsive MBP kinase activity was accounted for by five distinct MAP kinase isoforms detected by Western immunoblotting. All had negligible activity in cultured fetal hepatocytes under basal conditions. Treatment of fetal hepatocytes with hepatocyte growth factor led to activation of the predominant isoforms, relative molecular weight (M(r)) = 42,000 and 44,000 in a manner indistinguishable from TGF-alpha, whereas insulin had no effect. All five of the immunoreactive MAP kinases were present in both fetal and adult liver homogenates. The M(r) = 42,000 and 44,000 isoforms were only minimally activated in vivo. We conclude that the mitogen-independent growth exhibited by fetal hepatocytes in primary culture is not associated with tonic activation of the MAP kinase system. Our data support the possibility that fetal hepatic growth may be, in part, independent of the action of growth factors as mediated via the MAP kinase system.

Phosphorylation of caldesmon by ERK MAP kinases in smooth muscle

2000 ◽  
Vol 278 (4) ◽  
pp. C718-C726 ◽  
Author(s):  
Jason C. Hedges ◽  
Brian C. Oxhorn ◽  
Michael Carty ◽  
Leonard P. Adam ◽  
Ilia A. Yamboliev ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Map Kinase ◽  
Map Kinases ◽  
Isometric Force ◽  
Phosphorylation Site ◽  
Smooth Muscle Contraction ◽  
Tracheal Smooth Muscle ◽  
Muscarinic Agonists

Phosphorylation of h-caldesmon has been proposed to regulate airway smooth muscle contraction. Both extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases phosphorylate h-caldesmon in vitro. To determine whether both enzymes phosphorylate caldesmon in vivo, phosphorylation-site-selective antibodies were used to assay phosphorylation of MAP kinase consensus sites. Stimulation of cultured tracheal smooth muscle cells with ACh or platelet-derived growth factor increased caldesmon phosphorylation at Ser789 by about twofold. Inhibiting ERK MAP kinase activation with 50 μM PD-98059 blocked agonist-induced caldesmon phosphorylation completely. Inhibiting p38 MAP kinases with 25 μM SB-203580 had no effect on ACh-induced caldesmon phosphorylation. Carbachol stimulation increased caldesmon phosphorylation at Ser789 in intact tracheal smooth muscle, which was blocked by the M2 antagonist AF-DX 116 (1 μM). AF-DX 116 inhibited carbachol-induced isometric contraction by 15 ± 1.4%, thus dissociating caldesmon phosphorylation from contraction. Activation of M2 receptors leads to activation of ERK MAP kinases and phosphorylation of caldesmon with little or no functional effect on isometric force. P38 MAP kinases are also activated by muscarinic agonists, but they do not phosphorylate caldesmon in vivo.

Coupling of M2 muscarinic receptors to ERK MAP kinases and caldesmon phosphorylation in colonic smooth muscle

2000 ◽  
Vol 278 (3) ◽  
pp. G429-G437 ◽  
Author(s):  
Amy K. Cook ◽  
Michael Carty ◽  
Cherie A. Singer ◽  
Ilia A. Yamboliev ◽  
William T. Gerthoffer
Keyword(s):  
Smooth Muscle ◽  
Map Kinase ◽  
Muscarinic Receptors ◽  
Map Kinases ◽  
Kinase Inhibitor ◽  
Receptor Activation ◽  
Inhibitory Effect ◽  
Subsequent Treatment ◽  
P38 Map Kinase

Coupling of M2 and M3 muscarinic receptors to activation of mitogen-activated protein (MAP) kinases and phosphorylation of caldesmon was studied in canine colonic smooth muscle strips in which M3 receptors were selectively inactivated by N, N-dimethyl-4-piperidinyl diphenylacetate (4-DAMP) mustard (40 nM). ACh elicited activation of extracellular signal-regulated kinase (ERK) 1, ERK2, and p38 MAP kinases in control muscles and increased phosphorylation of caldesmon (Ser789), a putative downstream target of MAP kinases. Alkylation of M3 receptors with 4-DAMP had only a modest inhibitory effect on ERK activation, p38 MAP kinase activation, and caldesmon phosphorylation. Subsequent treatment with 1 μM AF-DX 116 completely prevented activation of ERK and p38 MAP kinase and prevented caldesmon phosphorylation. Caldesmon phosphorylation was blocked by the MAP kinase/ERK kinase inhibitor PD-98509 but not by the p38 MAP kinase inhibitor SB-203580. These results indicate that colonic smooth muscle M2 receptors are coupled to ERK and p38 MAP kinases. Activation of ERK, but not p38 MAP kinases, results in phosphorylation of caldesmon in vivo, which is a novel function for M2receptor activation in smooth muscle.

scholarly journals Activation of MAP kinase-activated protein kinase 2 in human neutrophils after phorbol ester or fMLP peptide stimulation

Blood ◽  
1996 ◽  
Vol 87 (12) ◽  
pp. 5287-5296 ◽  
Author(s):  
YL Zu ◽  
Y Ai ◽  
A Gilchrist ◽  
ME Labadia ◽  
RI Sha'afi ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Enzymatic Activity ◽  
Map Kinase ◽  
Phorbol Ester ◽  
Map Kinases ◽  
Phosphorylation Site ◽  
Human Neutrophils ◽  
Inhibitory Peptide

In response to extracellular stimulation, one of the earliest events in human neutrophils is protein phosphorylation, which mediates signal transduction and leads to the regulation of cellular functions. Mitogen- activated protein (MAP) kinases are rapidly activated by a variety of mitogens, cytokines, and stresses. The activated MAP kinases in turn regulate their substrate molecules by phosphorylation. MAP kinase- activated protein (MAPKAP) kinase 2, a Ser/Thr kinase, has been shown to be phosphorylated by p38 MAP kinase both in vivo and in vitro. Phosphorylation of the Thr-334 site of MAPKAP kinase 2 results in a conformational change with subsequent activation of the enzyme. To better define the role of MAPKAP kinase 2 in the activation of human neutrophils, its enzymatic activity was measured after stimulation by either a phorbol ester (phorbol myristate acetate [PMA]), a potent protein kinase C activator, or the tripeptide fMLP, which is a chemotactic factor. The in vitro kinase assays indicate that both PMA and fMLP stimulated a transient increase in the enzymatic activity of cellular MAPKAP kinase 2. The induced kinase activation was concentration-dependent and reached a maximum at 5 minutes for PMA and 1 minute for fMLP. To identify potential substrate molecules for MAPKAP kinase 2, a highly active kinase mutant was generated by mutating the MAP kinase phosphorylation site in the C-terminal region. The replacement of threonine 334 with alanine resulted in a marked augmentation of catalytic activity. Analysis of in vitro protein phosphorylation in the presence of the active kinase indicates that a 60-kD cytosolic protein (p60) was markedly phosphorylated and served as the major substrate for MAPKAP kinase 2 in human neutrophils. Based on the MAPKAP kinase 2 phosphorylation site of Hsp27, a competitive inhibitory peptide was synthesized. This competitive inhibitory peptide specifically inhibited MAPKAP kinase 2 enzymatic activity, as well as the in vitro and in vivo kinase-induced p60 phosphorylation. To assess the contribution of MAPKAP kinase 2 in neutrophil function, the oxidative burst response after manipulation of endogenous kinase activity was measured. Intracellular delivery of the competitive inhibitory peptide into human neutrophils reduced both PMA- and fMLP- stimulated superoxide anion production. Thus, the results strongly suggest that MAPKAP kinase 2 is involved in the activation of human neutrophils.

scholarly journals c-Jun N-terminal phosphorylation correlates with activation of the JNK subgroup but not the ERK subgroup of mitogen-activated protein kinases.

1994 ◽  
Vol 14 (10) ◽  
pp. 6683-6688 ◽  
Author(s):  
A Minden ◽  
A Lin ◽  
T Smeal ◽  
B Dérijard ◽  
M Cobb ◽  
...  
Keyword(s):  
Map Kinase ◽  
Map Kinases ◽  
New Members ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
Extracellular Stimuli ◽  
Terminal Site ◽  
Stimulation Of

c-Jun transcriptional activity is stimulated by phosphorylation at two N-terminal sites: Ser-63 and -73. Phosphorylation of these sites is enhanced in response to a variety of extracellular stimuli, including growth factors, cytokines, and UV irradiation. New members of the mitogen-activated protein (MAP) kinase group of signal-transducing enzymes, termed JNKs, bind to the activation domain of c-Jun and specifically phosphorylate these sites. However, the N-terminal sites of c-Jun were also suggested to be phosphorylated by two other MAP kinases, ERK1 and ERK2. Despite these reports, we find that unlike the JNKs, ERK1 and ERK2 do not phosphorylate the N-terminal sites of c-Jun in vitro; instead they phosphorylate an inhibitory C-terminal site. Furthermore, the phosphorylation of c-Jun in vivo at the N-terminal sites correlates with activation of the JNKs but not the ERKs. The ERKs are probably involved in the induction of c-fos expression and thereby contribute to the stimulation of AP-1 activity. Our study suggests that two different branches of the MAP kinase group are involved in the stimulation of AP-1 activity through two different mechanisms.

scholarly journals SRC family kinase (SFK) inhibition reduces rhabdomyosarcoma cell growth in vitro and in vivo and triggers p38 MAP kinase-mediated differentiation

Oncotarget ◽  
2015 ◽  
Vol 6 (14) ◽  
pp. 12421-12435 ◽  
Author(s):  
Nadia Casini ◽  
Iris Maria Forte ◽  
Gianmarco Mastrogiovanni ◽  
Francesca Pentimalli ◽  
Adriano Angelucci ◽  
...  
Keyword(s):  
Cell Growth ◽  
Map Kinase ◽  
P38 Map Kinase ◽  
Src Family Kinase ◽  
Rhabdomyosarcoma Cell

Abstract 68: p38 MAP Kinase Regulates Chamber Specific Postnatal Remodelling of Cardiac Ventricles

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Tomohiro Yokota ◽  
Jin Li ◽  
Qing Zhang ◽  
Yichen Ding ◽  
Kevin Sung ◽  
...  
Keyword(s):  
Map Kinase ◽  
Kinase Activity ◽  
P38 Map Kinase ◽  
Mouse Heart ◽  
Neonatal Lethality ◽  
Cardiac Ventricles ◽  
Inner Diameter ◽  
Apoptotic Activity ◽  
Myocyte Proliferation

Background: Left ventricle (LV) and right ventricle (RV) in mouse heart undergo dramatically different chamber-specific remodeling after birth, leading to rapid increase in LV vs. RV chamber size. However, the underlying regulatory mechanism mediating chamber specific remodeling process remains enigmatic. Results and Methods: In neonatal mouse heart, p38 MAP kinase activity is dynamically activated in a chamber specific manner. p38 activity is specifically elevated in RV comparing to LV at E18.5, postnatal day 3 (P3) and P7 stages whereas p38 activity is lower in both ventricles at P0 and P1. In mouse heart with cardiomyocyte specific-knockout of p38α and β (p38ab-cdKO), total p38 activity was diminished in both chambers. The p38ab-cdKO mice had significant neonatal lethality associated with RV specific chamber enlargement and significant increase in both RV wall thickness (RVW) and inner diameter of RV (RVID) as early as P3. Interestingly, p38 inactivation suppressed myocyte apoptotic activity specifically in RV while increased RV myocyte proliferation and hypertrophy during neonatal period. Unexpectedly, RNA-seq results implicated Xbp1 mediated transcriptional regulation significantly contributing to p38 dependent transcriptome reprogramming in RV. Indeed, IRE1α expression in neonatal cardiomyocyte is sufficient to induce proliferation in vitro. Furthermore, knockdown of Xbp1 blunted p38 inhibition-induced myocyte proliferation, suggesting that IRE1a/Xbp1 mediate p38 signaling in neonatal myocyte proliferation. Conclusion: Chamber-specific remodeling in neonatal heart involves temporally regulated and RV specific p38 MAP kinase activity. RV specific myocyte proliferation and hypertrophy concurrent with RV specific programmed myocyte death is orchestrated by two innate stress-response pathways, p38 and Xbp1.

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