5′-AMP-activated protein kinase activity and subunit expression in exercise-trained human skeletal muscle

2003 ◽  
Vol 94 (2) ◽  
pp. 631-641 ◽  
Author(s):  
Jakob N. Nielsen ◽  
Kirsty J. W. Mustard ◽  
Drew A. Graham ◽  
Haiyan Yu ◽  
Christopher S. MacDonald ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Exercise Training ◽  
Human Skeletal Muscle ◽  
Protein Kinase Activity ◽  
Trained Subjects ◽  
Protein Levels ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase ◽  
Sedentary Subjects

5′-AMP-activated protein kinase (AMPK) has been proposed to be a pivotal factor in cellular responses to both acute exercise and exercise training. To investigate whether protein levels and gene expression of catalytic (α1, α2) and regulatory (β1, β2, γ1, γ2, γ3) AMPK subunits and exercise-induced AMPK activity are influenced by exercise training status, muscle biopsies were obtained from seven endurance exercise-trained and seven sedentary young healthy men. The α1- and α2-AMPK mRNA contents in trained subjects were both 117 ± 2% of that in sedentary subjects (not significant), whereas mRNA for γ3 was 61 ± 1% of that in sedentary subjects (not significant). The level of α1-AMPK protein in trained subjects was 185 ± 34% of that in sedentary subjects ( P < 0.05), whereas the levels of the remaining subunits (α2, β1, β2, γ1, γ2, γ3) were similar in trained and sedentary subjects. At the end of 20 min of cycle exercise at 80% of peak O2 uptake, the increase in phosphorylation of α-AMPK (Thr172) was blunted in the trained group (138 ± 38% above rest) compared with the sedentary group (353 ± 63% above rest) ( P < 0.05). Acetyl CoA-carboxylase β-phosphorylation (Ser221), which is a marker for in vivo AMPK activity, was increased by exercise in both groups but to a lower level in trained subjects (32 ± 5 arbitrary units) than in sedentary controls (45 ± 1 arbitrary units) ( P < 0.01). In conclusion, trained human skeletal muscle has increased α1-AMPK protein levels and blunted AMPK activation during exercise.

5′-AMP-activated protein kinase activity and protein expression are regulated by endurance training in human skeletal muscle

2004 ◽  
Vol 286 (3) ◽  
pp. E411-E417 ◽  
Author(s):  
Christian Frøsig ◽  
Sebastian B. Jørgensen ◽  
D. Grahame Hardie ◽  
Erik A. Richter ◽  
Jørgen F. P. Wojtaszewski
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Exercise Training ◽  
Protein Content ◽  
Endurance Training ◽  
Human Skeletal Muscle ◽  
Protein Kinase Activity ◽  
Local Contraction ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The 5′-AMP-activated protein kinase (AMPK) is proposed to be involved in signaling pathways leading to adaptations in skeletal muscle in response to both a single exercise bout and exercise training. This study investigated the effect of endurance training on protein content of catalytic (α1, α2) and regulatory (β1, β2 and γ1, γ2, γ3) subunit isoforms of AMPK as well as on basal AMPK activity in human skeletal muscle. Eight healthy young men performed supervised one-legged knee extensor endurance training for 3 wk. Muscle biopsies were obtained before and 15 h after training in both legs. In response to training the protein content of α1, β2 and γ1 increased in the trained leg by 41, 34, and 26%, respectively (α1 and β2 P < 0.005, γ1 P < 0.05). In contrast, the protein content of the regulatory γ3-isoform decreased by 62% in the trained leg ( P = 0.01), whereas no effect of training was seen for α2, β1, and γ2. AMPK activity associated with the α1- and the α2-isoforms increased in the trained leg by 94 and 49%, respectively (both P < 0.005). In agreement with these observations, phosphorylation of α-AMPK-(Thr172) and of the AMPK target acetyl-CoA carboxylase-β(Ser221) increased by 74 and 180%, respectively (both P < 0.001). Essentially similar results were obtained in four additional subjects studied 55 h after training. This study demonstrates that protein content and basal AMPK activity in human skeletal muscle are highly susceptible to endurance exercise training. Except for the increase in γ1 protein, all observed adaptations to training could be ascribed to local contraction-induced mechanisms, since they did not occur in the contralateral untrained muscle.

Exercise Induces Isoform-Specific Increase in 5′AMP-Activated Protein Kinase Activity in Human Skeletal Muscle

2000 ◽  
Vol 273 (3) ◽  
pp. 1150-1155 ◽  
Author(s):  
Nobuharu Fujii ◽  
Tatsuya Hayashi ◽  
Michael F. Hirshman ◽  
Jeremy T. Smith ◽  
Susan A. Habinowski ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Human Skeletal Muscle ◽  
Kinase Activity ◽  
Protein Kinase Activity ◽  
Specific Increase ◽  
Amp Activated Protein Kinase

scholarly journals ADP is the dominant controller of AMP-activated protein kinase activity dynamics in skeletal muscle during exercise

2019 ◽  
Author(s):  
Ian F. Coccimiglio ◽  
David C. Clarke
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Adenine Nucleotides ◽  
Protein Kinase Activity ◽  
Global Parameter ◽  
Cellular Energy ◽  
Direct Binding ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase ◽  
Activity Dynamics

AbstractExercise training elicits profound metabolic adaptations in skeletal muscle cells. A key molecule in coordinating these adaptations is AMP-activated protein kinase (AMPK), whose activity increases in response to cellular energy demand. AMPK activity dynamics are primarily controlled by the adenine nucleotides ADP and AMP, but how each contributes to its control in skeletal muscle during exercise is unclear. We developed and validated a mathematical model of AMPK signaling dynamics, and then applied global parameter sensitivity analyses with data-informed constraints to predict that AMPK activity dynamics are determined principally by ADP and not AMP. We then used the model to predict the effects of two additional direct-binding activators of AMPK, ZMP and Compound 991, further validating the model and demonstrating its applicability to understanding AMPK pharmacology. The relative effects of direct-binding activators can be understood in terms of four properties, namely their concentrations, binding affinities for AMPK, abilities to enhance AMPK phosphorylation, and the magnitudes of their allosteric activation of AMPK. Despite AMP’s favorable values in three of these four properties, ADP is the dominant controller of AMPK activity dynamics in skeletal muscle during exercise by virtue of its higher concentration.Author SummaryDuring exercise, the enzyme “AMP-activated protein kinase” (AMPK) detects the disrupted cellular energy state by binding to the adenine nucleotides ATP, ADP, and AMP, which are the major chemical energy carriers of the cell. How the adenine nucleotides interact to control AMPK activity is poorly understood. In this study, we used mathematical modeling to investigate the control of AMPK activity by the adenine nucleotides in skeletal muscle during exercise. We simulated the model many times with randomly generated parameter sets. Ultimately the parameters affect four key properties of an AMPK activator, namely its concentration, the tightness with which it binds to AMPK, its ability to activate AMPK by promoting its phosphorylation, and its ability to activate AMPK through allostery. We found that ADP is the dominant controller of AMPK activity, instead of AMP, due to its high concentration relative to that of AMP. We also modeled AMPK activity in response to drugs that activate it, which further demonstrated the validity and applicability of the model. Overall, our research enhances understanding of AMPK action during exercise and could inform the development of drugs that target AMPK.

Regulation of 5′AMP-activated protein kinase activity and substrate utilization in exercising human skeletal muscle

2003 ◽  
Vol 284 (4) ◽  
pp. E813-E822 ◽  
Author(s):  
Jørgen F. P. Wojtaszewski ◽  
Christopher MacDonald ◽  
Jakob N. Nielsen ◽  
Ylva Hellsten ◽  
D. Grahame Hardie ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
High Energy ◽  
Protein Kinase Activity ◽  
High Energy Phosphates ◽  
Humoral Factors ◽  
Glycogen Concentration ◽  
Loaded State ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The metabolic role of 5′AMP-activated protein kinase (AMPK) in regulation of skeletal muscle metabolism in humans is unresolved. We measured isoform-specific AMPK activity and β-acetyl-CoA carboxylase (ACCβ) Ser221 phosphorylation and substrate balance in skeletal muscle of eight athletes at rest, during cycling exercise for 1 h at 70% peak oxygen consumption, and 1 h into recovery. The experiment was performed twice, once in a glycogen-loaded (glycogen concentration ∼900 mmol/kg dry wt) and once in a glycogen-depleted (glycogen concentration ∼160 mmol/kg dry wt) state. At rest, plasma long-chain fatty acids (FA) were twofold higher in the glycogen-depleted than in the loaded state, and muscle α1 AMPK (160%) and α2 AMPK (145%) activities and ACCβ Ser221phosphorylation (137%) were also significantly higher in the glycogen-depleted state. During exercise, α2 AMPK activity, ACCβ Ser221 phosphorylation, plasma catecholamines, and leg glucose and net FA uptake were significantly higher in the glycogen-depleted than in the glycogen-loaded state without apparent differences in muscle high-energy phosphates. Thus exercise in the glycogen-depleted state elicits an enhanced uptake of circulating fuels that might be associated with elevated muscle AMPK activation. It is concluded that muscle AMPK activity and ACCβ Ser221phosphorylation at rest and during exercise are sensitive to the fuel status of the muscle. During exercise, this dependence may in part be mediated by humoral factors.

scholarly journals Glucose regulates AMP-activated protein kinase activity and gene expression in clonal, hypothalamic neurons expressing proopiomelanocortin: additive effects of leptin or insulin

2007 ◽  
Vol 192 (3) ◽  
pp. 605-614 ◽  
Author(s):  
Fang Cai ◽  
Armen V Gyulkhandanyan ◽  
Michael B Wheeler ◽  
Denise D Belsham
Keyword(s):  
Protein Kinase ◽  
Energy Homeostasis ◽  
Cell Model ◽  
Neuronal Cell ◽  
Cell Types ◽  
Glucose Sensing ◽  
Protein Kinase Activity ◽  
Energy Status ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The mammalian hypothalamus comprises an array of phenotypically distinct cell types that interpret peripheral signals of energy status and, in turn, elicits an appropriate response to maintain energy homeostasis. We used a clonal representative hypothalamic cell model expressing proopiomelanocortin (POMC; N-43/5) to study changes in AMP-activated protein kinase (AMPK) activity and glucose responsiveness. We have demonstrated the presence of cellular machinery responsible for glucose sensing in the cell line, including glucokinase, glucose transporters, and appropriate ion channels. ATP-sensitive potassium channels were functional and responded to glucose. The N-43/5 POMC neurons may therefore be an appropriate cell model to study glucose-sensing mechanisms in the hypothalamus. In N-43/5 POMC neurons, increasing glucose concentrations decreased phospho-AMPK activity. As a relevant downstream effect, we found that POMC transcription increased with 2.8 and 16.7 mM glucose. Upon addition of leptin, with either no glucose or with 5 mM glucose, we found that leptin decreased AMPK activity in N-43/5 POMC neurons, but had no significant effect at 25 mM glucose, whereas insulin decreased AMPK activity at only 5 mM glucose. These results demonstrate that individual hypothalamic neuronal cell types, such as the POMC neuron, can have distinct responses to peripheral signals that relay energy status to the brain, and will therefore be activated uniquely to control neuroendocrine function.

scholarly journals Adrenaline is a critical mediator of acute exercise-induced AMP-activated protein kinase activation in adipocytes

2007 ◽  
Vol 403 (3) ◽  
pp. 473-481 ◽  
Author(s):  
Ho-Jin Koh ◽  
Michael F. Hirshman ◽  
Huamei He ◽  
Yangfeng Li ◽  
Yasuko Manabe ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein Kinase Activity ◽  
Chronic Exercise ◽  
Rat Adipocytes ◽  
Compound C ◽  
Isolated Adipocytes ◽  
Ampk Activity ◽  
Exercise Induced ◽  
Amp Activated Protein Kinase

Exercise increases AMPK (AMP-activated protein kinase) activity in human and rat adipocytes, but the underlying molecular mechanisms and functional consequences of this activation are not known. Since adrenaline (epinephrine) concentrations increase with exercise, in the present study we hypothesized that adrenaline activates AMPK in adipocytes. We show that a single bout of exercise increases AMPKα1 and α2 activities and ACC (acetyl-CoA carboxylase) Ser79 phosphorylation in rat adipocytes. Similarly to exercise, adrenaline treatment in vivo increased AMPK activities and ACC phosphorylation. Pre-treatment of rats with the β-blocker propranolol fully blocked exercise-induced AMPK activation. Increased AMPK activity with exercise and adrenaline treatment in vivo was accompanied by an increased AMP/ATP ratio. Adrenaline incubation of isolated adipocytes also increased the AMP/ATP ratio and AMPK activities, an effect blocked by propranolol. Adrenaline incubation increased lipolysis in isolated adipocytes, and Compound C, an AMPK inhibitor, attenuated this effect. Finally, a potential role for AMPK in the decreased adiposity associated with chronic exercise was suggested by marked increases in AMPKα1 and α2 activities in adipocytes from rats trained for 6 weeks. In conclusion, both acute and chronic exercise are significant regulators of AMPK activity in rat adipocytes. Our findings suggest that adrenaline plays a critical role in exercise-stimulated AMPKα1 and α2 activities in adipocytes, and that AMPK can function in the regulation of lipolysis.

Oral glucose ingestion attenuates exercise-induced activation of 5′-AMP-activated protein kinase in human skeletal muscle

2006 ◽  
Vol 342 (3) ◽  
pp. 949-955 ◽  
Author(s):  
Thorbjorn C.A. Akerstrom ◽  
Jesper B. Birk ◽  
Ditte K. Klein ◽  
Christian Erikstrup ◽  
Peter Plomgaard ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Human Skeletal Muscle ◽  
Oral Glucose ◽  
Glucose Ingestion ◽  
Exercise Induced ◽  
Amp Activated Protein Kinase

Hypoxia and AMP independently regulate AMP-activated protein kinase activity in heart

2005 ◽  
Vol 288 (5) ◽  
pp. H2412-H2421 ◽  
Author(s):  
Markus Frederich ◽  
Li Zhang ◽  
James A. Balschi
Keyword(s):  
Protein Kinase ◽  
Metabolic Inhibitors ◽  
Protein Kinase Activity ◽  
Α Subunit ◽  
Rat Hearts ◽  
Upstream Kinase ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The hypothesis was tested that hypoxia increases AMP-activated protein kinase (AMPK) activity independently of AMP concentration ([AMP]) in heart. In isolated perfused rat hearts, cytosolic [AMP] was changed from 0.2 to 16 μM using metabolic inhibitors during both normal oxygenation (95% O2-5% CO2, normoxia) and limited oxygenation (95% N2-5% CO2, hypoxia). Total AMPK activity measured in vitro ranged from 2 to 40 pmol·min−1·mg protein−1 in normoxic hearts and from 5 to 55 pmol·min−1·mg protein−1 in hypoxic hearts. The dependence of the in vitro total AMPK activity on the in vivo cytosolic [AMP] was determined by fitting the measurements from individual hearts to a hyperbolic equation. The [AMP] resulting in half-maximal total AMPK activity ( A0.5) was 3 ± 1 μM for hypoxic hearts and 28 ± 13 μM for normoxic hearts. The A0.5 for α2-isoform AMPK activity was 2 ± 1 μM for hypoxic hearts and 13 ± 8 μM for normoxic hearts. Total AMPK activity correlated with the phosphorylation of the Thr172 residue of the AMPK α-subunit. In potassium-arrested hearts perfused with variable O2 content, α-subunit Thr172 phosphorylation increased at O2 ≤ 21% even though [AMP] was <0.3 μM. Thus hypoxia or O2 ≤ 21% increased AMPK phosphorylation and activity independently of cytosolic [AMP]. The hypoxic increase in AMPK activity may result from either direct phosphorylation of Thr172 by an upstream kinase or reduction in the A0.5 for [AMP].

Skeletal muscle basal AMP-activated protein kinase activity is chronically elevated in alloxan-diabetic dogs: impact of exercise

2003 ◽  
Vol 95 (4) ◽  
pp. 1523-1530 ◽  
Author(s):  
Michael J. Christopher ◽  
Zhi-Ping Chen ◽  
Christian Rantzau ◽  
Bruce E. Kemp ◽  
Frank P. Alford
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Vastus Lateralis ◽  
Glucose Disposal ◽  
Protein Kinase Activity ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Peripheral Tissues ◽  
Diabetic Dogs ◽  
Amp Activated Protein Kinase

The effect of diabetes and exercise on skeletal muscle (SkM) AMP-activated protein kinase (AMPK)α1 and -α2 activities and site-specific phosphorylation of acetyl-CoA carboxylase was examined in the same six dogs before alloxan (35 mg/kg)-induced diabetes (C) and after 4-5 wk of suboptimally controlled hyperglycemic and hypoinsulinemic diabetes (DHG) in the presence and absence of 300-min phlorizin (50 μg·kg-1·min-1)-induced “normoglycemia” (DNG). In each study, the dog underwent a 150-min [3-3H]glucose infusion period, followed by a 30-min treadmill exercise test (60-70% maximal oxygen capacity) to measure the rate of glucose disposal into peripheral tissues (Rdtissue). SkM biopsies were taken from the thigh (vastus lateralis) before and immediately after exercise. In the C and DHG states, the rise in plasma free fatty acids (FFA) with exercise (∼40%) was similar. In the DNG group, preexercise FFA were significantly higher, but the absolute rise in FFA with exercise was similar. However, the exercise-induced increment in Rdtissue was significantly blunted (by ∼40-50%) in the DNG group compared with the other states. In SkM, preexercise AMPKα1 and -α2 activities were significantly elevated (by ∼60-125%) in both diabetic states, but unlike the C group these activities did not rise further with exercise. Additionally, preexercise acetyl-CoA carboxylase phosphorylation in both diabetic states was elevated by ∼70-80%, but the increases with exercise were similar to the C group. Preexercise AMPKα1 and -α2 activities were negatively correlated with Rdtissue during exercise for the combined groups (both P < 0.02). In conclusion, the elevated preexercise SkM AMPKα1 and -α2 activities contribute to the ongoing basal supply of glucose and fatty acid metabolism in suboptimally controlled hypoinsulinemic diabetic dogs; but whether they also play a permissive role in the metabolic stress response to exercise remains uncertain.

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