Differential regulation of MAP kinase, p70S6K, and Akt by contraction and insulin in rat skeletal muscle

1999 ◽  
Vol 276 (5) ◽  
pp. E870-E878 ◽  
Author(s):  
Daniel J. Sherwood ◽  
Scott D. Dufresne ◽  
Jeffrey F. Markuns ◽  
Bentley Cheatham ◽  
David E. Moller ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Map Kinase ◽  
Contractile Activity ◽  
Kinase Signaling ◽  
Rat Skeletal Muscle ◽  
S6 Kinase ◽  
Map Kinase Signaling ◽  
Map Kinase Pathway ◽  
Kinase Pathway ◽  
Stimulation Of

To study the effects of contractile activity on mitogen-activated protein kinase (MAP kinase), p70 S6 kinase (p70S6K), and Akt kinase signaling in rat skeletal muscle, hindlimb muscles were contracted by electrical stimulation of the sciatic nerve for periods of 15 s to 60 min. Contraction resulted in a rapid and transient activation of Raf-1 and MAP kinase kinase 1, a rapid and more sustained activation of MAP kinase and the 90-kDa ribosomal S6 kinase 2, and a dramatic increase in c- fos mRNA expression. Contraction also resulted in an apparent increase in the association of Raf-1 with p21Ras, although stimulation of MAP kinase signaling occurred independent of Shc, IRS1, and IRS2 tyrosine phosphorylation or the formation of Shc/Grb2 or IRS1/Grb2 complexes. Insulin was considerably less effective than contraction in stimulating the MAP kinase pathway. However, insulin, but not contraction, increased p70S6K and Akt activities in the muscle. These results demonstrate that contraction-induced activation of the MAP kinase pathway is independent of proximal steps in insulin and/or growth factor-mediated signaling, and that contraction and insulin have discordant effects with respect to the activation of the MAP kinase pathway vs. p70S6K and Akt. Of the numerous stimulators of MAP kinase in skeletal muscle, contractile activity emerges as a potent and physiologically relevant activator of MAP kinase signaling, and thus activation of this pathway is likely to be an important molecular mechanism by which skeletal muscle cells transduce mechanical and/or biochemical signals into downstream biological responses.

scholarly journals The inhibition of glycogen synthase kinase-3 by insulin or insulin-like growth factor 1 in the rat skeletal muscle cell line L6 is blocked by wortmannin, but not by rapamycin: evidence that wortmannin blocks activation of the mitogen-activated protein kinase pathway in L6 cells between Ras and Raf

1994 ◽  
Vol 303 (1) ◽  
pp. 21-26 ◽  
Author(s):  
D A E Cross ◽  
D R Alessi ◽  
J R Vandenheede ◽  
H E McDowell ◽  
H S Hundal ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Map Kinase ◽  
Protein Phosphatase ◽  
Glycogen Synthase ◽  
Glycogen Synthase Kinase 3 ◽  
Rat Skeletal Muscle ◽  
S6 Kinase ◽  
P70 S6 Kinase ◽  
Skeletal Muscle Cell Line ◽  
Stimulation Of

Glycogen synthase kinase-3 (GSK3) is inactivated in vitro by p70 S6 kinase or MAP kinase-activated protein kinase-1 beta (MAPKAP kinase-1 beta; also known as Rsk-2). Here we show that GSK3 isoforms are inhibited by 40% within minutes after stimulation of the rat skeletal-muscle cell line L6 with insulin-like growth factor-1 (IGF-1) or insulin. GSK3 was similarly inhibited in rabbit skeletal muscle after an intravenous injection of insulin. Inhibition resulted from increased phosphorylation of GSK3, probably at a serine/threonine residue(s), because it was reversed by incubation with protein phosphatase-2A. Rapamycin blocked the activation of p70 S6 kinase by IGF-1 in L6 cells, but had no effect on the inhibition of GSK3 or the activation of MAPKAP kinase-1 beta. In contrast, wortmannin, a potent inhibitor of PtdIns 3-kinase, prevented the inactivation of GSK3 and the activation of MAPKAP kinase-1 beta and p70 S6 kinase by IGF-1 or insulin. Wortmannin also blocked the activation of p74raf-1. MAP kinase kinase and p42 MAP kinase, but not the formation of GTP-Ras by IGF-1. The results suggest that the stimulation of glycogen synthase by insulin/IGF-1 in skeletal muscle involves the MAP-KAP kinase-1-catalysed inhibition of GSK3, as well as the previously described activation of the glycogen-associated form of protein phosphatase-1.

Extracellular-regulated protein kinase cascades are activated in response to injury in human skeletal muscle

1998 ◽  
Vol 275 (2) ◽  
pp. C555-C561 ◽  
Author(s):  
Doron Aronson ◽  
Jørgen F. P. Wojtaszewski ◽  
Anders Thorell ◽  
Jonas Nygren ◽  
David Zangen ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Map Kinase ◽  
Muscle Injury ◽  
Human Skeletal Muscle ◽  
Signaling Cascades ◽  
Vastus Lateralis Muscle ◽  
Kinase Signaling ◽  
Transcriptional Responses ◽  
Map Kinase Signaling ◽  
Stimulation Of

The mitogen-activated protein (MAP) kinase signaling pathways are believed to act as critical signal transducers between stress stimuli and transcriptional responses in mammalian cells. However, it is not known whether these signaling cascades also participate in the response to injury in human tissues. To determine whether injury to the vastus lateralis muscle activates MAP kinase signaling in human subjects, two needle biopsies or open muscle biopsies were taken from the same incision site 30–60 min apart. The muscle biopsy procedures resulted in striking increases in dual phosphorylation of the extracellular-regulated kinases (ERK1 and ERK2) and in activity of the downstream substrate, the p90 ribosomal S6 kinase. Raf-1 kinase and MAP kinase kinase, upstream activators of ERK, were also markedly stimulated in all subjects. In addition, c-Jun NH2-terminal kinase and p38 kinase, components of two parallel MAP kinase pathways, were activated following muscle injury. The stimulation of the three MAP kinase cascades was present only in the immediate vicinity of the injury, a finding consistent with a local rather than systemic activation of these signaling cascades in response to injury. These data demonstrate that muscle injury induces the stimulation of the three MAP kinase cascades in human skeletal muscle, suggesting a physiological relevance of these protein kinases in the immediate response to tissue injury and possibly in the initiation of wound healing.

Tie2Cre B-Raf flox/flox Mice Reveal a Role for B-Raf in Tpo-Mediated Thrombopoiesis and Survival of Mature Megakaryocytes in Adult Hematopoiesis.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 200-200
Author(s):  
Tamihiro Kamata ◽  
Jing Kang ◽  
Alcino Silva ◽  
Rong Wang ◽  
Andrew D. Leavitt
Keyword(s):  
Bone Marrow ◽  
Map Kinase ◽  
Chimeric Mouse ◽  
Kinase Signaling ◽  
Western Blots ◽  
Map Kinase Signaling ◽  
Map Kinase Pathway ◽  
Kinase Pathway

Abstract Thrombopoietin (Tpo) is the primary cytokine regulator of megakaryocytopoiesis. Tpo engagement of its receptor, Mpl, activates the classic MAP kinase (Raf/MEK/ERK) pathway, but the biological role of MAP kinase signaling in megakaryocytopoiesis remains poorly defined. Raf family kinases control signal flow through the classic MAP kinase pathway from activated cytokine receptors. We therefore undertook a genetic approach to understand the role of MAP kinase signaling and to identify which Raf family member is important for megakaryocytopoiesis. Using data from in vitro B-raf-/- ES cell cultures, fetal liver hematopoietic cells from mid-gestation B-raf-/- embryos, and B-raf-/- chimeric mice, we recently reported that B-Raf acts in a cell autonomous manner to quantitatively affect megakaryocytopoiesis. However, limitations of the chimeric mouse model, and mid-gestation lethality of B-raf-/- embryos precluded a detailed mechanistic understanding of B-Raf activity or the evaluation of B-Raf in adult megakaryocytopoiesis. We therefore generated tissue-restricted B-Raf deficient mice by crossing B-rafflox/flox mice with mice expressing Cre recombinase controlled by the Tie2 promoter/enhancer. The Tie2Cre+/B-rafflox/flox mice were born with normal Mendelian genetics and without gross abnormalities. Circulating leukocytes demonstrated complete recombination of the floxed B-Raf allele, and western blots showed undetectable B-Raf expression in platelet, spleen, and thymus lysates, consistent with complete hematopoietic Cre-mediated recombination. Steady state platelet counts were not altered in the B-Raf deficient animals at baseline: Tie2Cre+/B-rafflox/flox mice = 788 +/−57 x 103/mm3; Tie2Cre-/B-rafflox/flox mice 800 +/−40 x 103/mm3 (p=0.76, n=4). However, Tie2Cre+/B-rafflox/flox mice had a markedly impaired platelet count rise following Tpo injection, with peak counts of 3,375 +/−752 x 103/mm3 compared with 5,320 +/−606 x 103/mm3 for Tie2Cre-/B-rafflox/flox mice (p=0.0147, n=4) at 6 days post injection. In vitro expansion of CD41+ cells from Tie2Cre+/B-rafflox/flox bone marrow was only a third that of control mice, suggesting that the impaired in vivo platelet rise following Tpo reflects, at least in part, a decreased expansion of megakaryocyte lineage cells. Day 4 Tie2Cre+/B-rafflox/flox bone marrow cultures also yielded decreased low (2N-8N) and high (>32N) ploidy CD41+ cells compared with marrow from Tie2Cre-/B-rafflox/flox mice, while intermediate (16N-32N) ploidy CD41+ megakaryocytes were relatively preserved. TUNEL analysis revealed increased apoptotic death of the high ploidy (>32N) cells, a second possible mechanism contributing to the impaired platelet rise following Tpo injection. Together, our data demonstrate that the B-Raf/MAP kinase pathway is required for normal adult Tpo-induced thrombopoiesis through its effect on megakaryocyte lineage expansion and apoptotic cell death of mature megakaryocytes. Additional analysis is now underway to more fully define the role of B-Raf in megakaryocytopoiesis, including detailed biochemical studies to determine how the absence of B-Raf impacts intracellular signaling during this complex developmental process.

Effects of exercise and insulin on mitogen-activated protein kinase signaling pathways in rat skeletal muscle

1996 ◽  
Vol 271 (2) ◽  
pp. E403-E408 ◽  
Author(s):  
L. J. Goodyear ◽  
P. Y. Chang ◽  
D. J. Sherwood ◽  
S. D. Dufresne ◽  
D. E. Moller
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Map Kinase ◽  
Signaling Pathways ◽  
Mammalian Cells ◽  
Mitogen Activated Protein Kinase ◽  
Kinase Signaling ◽  
Rat Skeletal Muscle ◽  
Map Kinase Signaling ◽  
Mitogen Activated Protein

Studies in mammalian cells have established the existence of at least three distinct mitogen-activated protein kinase (MAP kinase) signaling pathways that are activated by a variety of growth factors and/or environmental stressors. We determined whether physical exercise, a physiological stressor, and insulin, a metabolic stimulator and growth factor, activate the c-jun NH2-terminus kinase (JNK), the p38 kinase, and/or the extracellular regulatory kinases (ERK; p42MAPK and p44MAPK) signaling pathways in rat skeletal muscle. Animals were studied immediately after running on a motorized treadmill for 10-60 min (20 m/min, 10% grade) or 5-30 min after an intraperitoneal injection of insulin (20 U/rat). Exercise increased skeletal muscle JNK activity by two- to threefold throughout the time course studied, whereas insulin did not significantly increase JNK activity. The p38 activity was slightly stimulated by exercise and not by insulin. The ERK kinase pathway, as assessed by ribosomal S6 kinase-2 activity assays and phosphospecific p42MAPK/p4NAPK immunoblotting, was stimulated by both exercise and insulin. These data are the first demonstration of exercise stimulating multiple intracellular signaling pathways in skeletal muscle. Activation of these MAP kinase signaling pathways may mediate changes in skeletal muscle growth and metabolism that occur in response to exercise.

Skeletal muscle contractile activity in vitro stimulates mitogen-activated protein kinase signaling

1999 ◽  
Vol 277 (4) ◽  
pp. C701-C707 ◽  
Author(s):  
Tatsuya Hayashi ◽  
Michael F. Hirshman ◽  
Scott D. Dufresne ◽  
Laurie J. Goodyear
Keyword(s):  
Skeletal Muscle ◽  
Map Kinase ◽  
Neurotransmitter Release ◽  
Contractile Activity ◽  
Kinase Signaling ◽  
Map Kinase Signaling ◽  
Mitogen Activated Protein ◽  
Kinase Phosphorylation ◽  
Muscle Contractile

Physical exercise is a potent stimulator of mitogen-activated protein (MAP) kinase signaling. To determine if this activation is secondary to systemic responses to exercise or due to muscle contractile activity per se, an isolated muscle preparation was developed. Contractile activity in vitro significantly increased p44MAPK and p42MAPK phosphorylation by 2.9- and 2.4-fold, respectively. Contraction-stimulated MAP kinase phosphorylation was not decreased in the presence ofd-tubocurarine or calphostin C, suggesting that neither neurotransmitter release nor diacylglycerol-sensitive protein kinase C mediates the contraction-induced activation of this signaling cascade. However, PD-98059, an inhibitor of MAP kinase kinase (MEK), inhibited the contraction-induced increases in MAP kinase phosphorylation. PD-98059 did not alter contraction-induced increases in glucose uptake or glycogen synthase activity, demonstrating that MAP kinase signaling is not necessary for these important metabolic effects of contractile activity in skeletal muscle. These data suggest that contractile activity of the skeletal muscle fibers per se, and not responses to neurotransmitter release, hormones, or other systemic factors, is responsible for the stimulation of MAP kinase signaling with physical exercise.

Bradykinin-stimulated protein synthesis by myocytes is dependent on the MAP kinase pathway and p70S6K

1999 ◽  
Vol 276 (4) ◽  
pp. H1393-H1398 ◽  
Author(s):  
Rebecca H. Ritchie ◽  
James D. Marsh ◽  
Rick J. Schiebinger
Keyword(s):  
Protein Synthesis ◽  
Map Kinase ◽  
Mrna Translation ◽  
S6 Kinase ◽  
Mitogen Activated Protein ◽  
Map Kinase Pathway ◽  
Ribosomal S6 Kinase ◽  
Pathway Inhibition ◽  
Kinase Pathway ◽  
Stimulation Of

Bradykinin (BK) has a direct hypertrophic effect on rat ventricular cardiomyocytes (VCM) as defined by an increase in protein synthesis and an increase in atrial natriuretic peptide mRNA and secretion. In the current study, we have examined the dependence of BK-induced protein synthesis on activation of 90-kDa ribosomal S6 kinase (p90rsk) and 70-kDa S6 kinase (p70S6K). Both of these kinases possess the ability to phosphorylate the ribosomal protein S6, which plays an important role in initiating mRNA translation. Stimulation of adult VCM with 10 μM BK increased p90rsk activity by 2.5 ± 0.3-fold and increased p70S6Kactivity by 2.0 ± 0.3-fold. p90rsk is a terminal kinase in the mitogen-activated protein (MAP) kinase pathway. Inhibition of MAP kinase kinase activation by Raf in the MAP kinase pathway with PD-098059 (25 μM) blocked BK-stimulated activation of p90rsk by 70% and unexpectedly blocked p70S6K by 72%. Rapamycin inhibited BK-stimulated p70S6Kactivity by 93% but had no effect on p90rsk activation by BK. Inhibition of the MAP kinase pathway and p70S6K with PD-098059 was paralleled by changes in protein synthesis. BK (10 μM) increased [3H]phenylalanine incorporation by 27 ± 3 and 39 ± 6% in cultured adult and neonatal VCM, respectively. Treatment with PD-098059 or rapamycin abolished the increase in protein synthesis stimulated by BK. These results suggest that 1) BK activates p70S6K and p90rsk; 2) although both p70S6K and p90rsk have the potential to phosphorylate the ribosomal S6 protein, p70S6K and not p90rsk is the predominant kinase involved in increasing protein synthesis by BK; and 3) p70S6K activation is dependent on stimulation of the MAP kinase pathway at a point distal to Raf.

scholarly journals Dual-specificity phosphatase 4 is upregulated during skeletal muscle atrophy and modulates extracellular signal-regulated kinase activity

2019 ◽  
Vol 316 (4) ◽  
pp. C567-C581 ◽  
Author(s):  
Ashley N. Haddock ◽  
Sydney A. Labuzan ◽  
Amy E. Haynes ◽  
Caleb S. Hayes ◽  
Karina M. Kakareka ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Cell Differentiation ◽  
Map Kinase ◽  
Reporter Gene ◽  
Muscle Cell ◽  
Muscle Cells ◽  
Skeletal Muscle Atrophy ◽  
Kinase Signaling ◽  
Muscle Cell Differentiation ◽  
Map Kinase Signaling

Skeletal muscle atrophy results from disparate physiological conditions, including denervation, corticosteroid treatment, and aging. The purpose of this study was to describe and characterize the function of dual-specificity phosphatase 4 (Dusp4) in skeletal muscle after it was found to be induced in response to neurogenic atrophy. Quantitative PCR and Western blot analysis revealed that Dusp4 is expressed during myoblast proliferation but rapidly disappears as muscle cells differentiate. The Dusp4 regulatory region was cloned and found to contain a conserved E-box element that negatively regulates Dusp4 reporter gene activity in response to myogenic regulatory factor expression. In addition, the proximal 3′-untranslated region of Dusp4 acts in an inhibitory manner to repress reporter gene activity as muscle cells progress through the differentiation process. To determine potential function, Dusp4 was fused with green fluorescent protein, expressed in C2C12 cells, and found to localize to the nucleus of proliferating myoblasts. Furthermore, Dusp4 overexpression delayed C2C12 muscle cell differentiation and resulted in repression of a MAP kinase signaling pathway reporter gene. Ectopic expression of a Dusp4 dominant negative mutant blocked muscle cell differentiation and attenuated MAP kinase signaling by preferentially targeting the ERK1/2 branch, but not the p38 branch, of the MAP kinase signaling cascade in skeletal muscle cells. The findings presented in this study provide the first description of Dusp4 in skeletal muscle and suggest that Dusp4 may play an important role in the regulation of muscle cell differentiation by regulating MAP kinase signaling.

Effects of phenylarsine oxide on stimulation of glucose transport in rat skeletal muscle

1990 ◽  
Vol 258 (4) ◽  
pp. C648-C653 ◽  
Author(s):  
E. J. Henriksen ◽  
J. O. Holloszy
Keyword(s):  
Skeletal Muscle ◽  
Glucose Transport ◽  
Cytochalasin B ◽  
Contractile Activity ◽  
Transport Activity ◽  
Rat Skeletal Muscle ◽  
Phenylarsine Oxide ◽  
Muscle Glucose Transport ◽  
Glucose Analogue ◽  
Stimulation Of

The trivalent arsenical phenylarsine oxide (PAO) inhibits insulin-stimulated glucose transport in adipocytes and skeletal muscle through direct interactions with vicinal sulfhydryls. In muscle, glucose transport is also activated by contractile activity and hypoxia. It was therefore the purpose of the present study to investigate whether vicinal sulfhydryls are involved in the stimulation of glucose transport activity in the isolated rat epitrochlearis muscle by hypoxia or contractions. PAO (greater than 5 microM) caused a twofold increase in rate of transport of the nonmetabolizable glucose analogue 3-O-methylglucose (3-MG) that was completely prevented by cytochalasin B, the vicinal dithiol dimercaptopropanol, dantrolene, or 9-aminoacridine, both inhibitors of sarcoplasmic reticulum Ca2+ release, or omission of extracellular Ca2+. Although PAO treatment (greater than or equal to 20 microM) prevented approximately 80% of the increase in 3-MG transport caused by insulin, it resulted in only a approximately 50% inhibition of the stimulation of 3-MG transport by either hypoxia or contractile activity. PAO treatment (40 microM) of muscles already maximally stimulated by insulin, contractile activity, or hypoxia did not reverse the enhanced rate of 3-MG transport. These data suggest that vicinal sulfhydryls play a greater role in the activation of glucose transport by insulin than by muscle contractions or hypoxia. The finding that PAO inhibits the stimulation of glucose transport, but does not affect glucose transport after it has been stimulated, provides evidence that vicinal sulfhydryls are involved in the pathways for glucose transport activation in muscle, but not in the glucose transport mechanism itself.

Induction of fetal hemoglobin expression by the histone deacetylase inhibitor apicidin

Blood ◽  
2003 ◽  
Vol 101 (5) ◽  
pp. 2001-2007 ◽  
Author(s):  
Olaf Witt ◽  
Sven Mönkemeyer ◽  
Gabi Rönndahl ◽  
Bernhard Erdlenbruch ◽  
Dirk Reinhardt ◽  
...  
Keyword(s):  
Map Kinase ◽  
Histone Deacetylase ◽  
Molecular Mechanisms ◽  
Trichostatin A ◽  
Hdac Inhibitors ◽  
Fetal Hemoglobin ◽  
Kinase Signaling ◽  
Potent Inducer ◽  
Map Kinase Signaling ◽  
Stimulation Of

Pharmacologic stimulation of fetal hemoglobin (HbF) expression may be a promising approach for the treatment of β-thalassemia. In this study, we have investigated the HbF-inducing activity and molecular mechanisms of specific histone deacetylase (HDAC) inhibitors in human K562 erythroleukemia cells. Apicidin was the most potent agent compared with other HDAC inhibitors (trichostatin A, MS-275, HC-toxin, suberoylanilide hydroxamic acid [SAHA]) and previously tested compounds (butyrate, phenylbutyrate, isobutyramide, hydroxyurea, 5-aza-cytidine), leading to a 10-fold stimulation of HbF expression at nanomolar to micromolar concentrations. Hyperacetylation of histones correlated with the ability of HDAC inhibitors to stimulate HbF synthesis. Furthermore, analysis of different mitogen-activated protein (MAP) kinase signaling pathways revealed that p38 signaling was activated following apicidin treatment of cells and that inhibition of this pathway abolished the HbF-inducing effect of apicidin. Additionally, activation of the Aγ-globin promoter by apicidin could be inhibited by p38 inhibitor SB203580. In summary, the novel HDAC inhibitor apicidin was found to be a potent inducer of HbF synthesis in K562 cells. The present data outline the role of histone hyperacetylation and p38 MAP kinase signaling as molecular targets for pharmacologic stimulation of HbF production in erythroid cells.

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