AMP-activated protein kinase regulates gene expression by direct phosphorylation of nuclear proteins

2003 ◽  
Vol 31 (1) ◽  
pp. 224-227 ◽  
Author(s):  
T. Leff
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Protein Kinase ◽  
Gene Transcription ◽  
Metabolic Pathways ◽  
Energy Charge ◽  
Nuclear Proteins ◽  
Cellular Energy ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

One of the primary functions of AMP-activated protein kinase (AMPK) is to regulate the metabolic pathways in response to reduced cellular energy charge. Most of the known targets of the kinase are cytoplasmic enzymes involved in both catabolic and anabolic metabolism. In addition, activation of AMPK in many cells results in changes in the pattern of gene expression. Although some of these effects are undoubtedly secondary responses to modified cellular metabolism, it is possible that in addition to its well-characterized function in the cytoplasm, AMPK also directly phosphorylates and regulates proteins involved in gene transcription. There are now several examples of transcription factors, cofactors and components of the transcriptional core machinery that are directly phosphorylated and regulated by AMPK. Here I review these examples and discuss the significance of AMPK activity in the nucleus.

scholarly journals Characterization of the Role of AMP-Activated Protein Kinase in the Regulation of Glucose-Activated Gene Expression Using Constitutively Active and Dominant Negative Forms of the Kinase

2000 ◽  
Vol 20 (18) ◽  
pp. 6704-6711 ◽  
Author(s):  
Angela Woods ◽  
Dalila Azzout-Marniche ◽  
Marc Foretz ◽  
Silvie C. Stein ◽  
Patricia Lemarchand ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Fatty Acid Synthase ◽  
Physiological Role ◽  
Rat Hepatocytes ◽  
Dominant Negative ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase ◽  
Constitutively Active

ABSTRACT In the liver, glucose induces the expression of a number of genes involved in glucose and lipid metabolism, e.g., those encoding L-type pyruvate kinase and fatty acid synthase. Recent evidence has indicated a role for the AMP-activated protein kinase (AMPK) in the inhibition of glucose-activated gene expression in hepatocytes. It remains unclear, however, whether AMPK is involved in the glucose induction of these genes. In order to study further the role of AMPK in regulating gene expression, we have generated two mutant forms of AMPK. One of these (α1312) acts as a constitutively active kinase, while the other (α1DN) acts as a dominant negative inhibitor of endogenous AMPK. We have used adenovirus-mediated gene transfer to express these mutants in primary rat hepatocytes in culture in order to determine their effect on AMPK activity and the transcription of glucose-activated genes. Expression of α1312 increased AMPK activity in hepatocytes and blocked completely the induction of a number of glucose-activated genes in response to 25 mM glucose. This effect is similar to that observed following activation of AMPK by 5-amino-imidazolecarboxamide riboside. Expression of α1DN markedly inhibited both basal and stimulated activity of endogenous AMPK but had no effect on the transcription of glucose-activated genes. Our results suggest that AMPK is involved in the inhibition of glucose-activated gene expression but not in the induction pathway. This study demonstrates that the two mutants we have described will provide valuable tools for studying the wider physiological role of AMPK.

scholarly journals AMP-activated protein kinase: an ultrasensitive system for monitoring cellular energy charge

1999 ◽  
Vol 338 (3) ◽  
pp. 717 ◽  
Author(s):  
D. Grahame HARDIE ◽  
Ian P. SALT ◽  
Simon A. HAWLEY ◽  
Stephen P. DAVIES
Keyword(s):  
Protein Kinase ◽  
Energy Charge ◽  
Cellular Energy ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase regulation and action in skeletal muscle during exercise

2003 ◽  
Vol 31 (1) ◽  
pp. 191-195 ◽  
Author(s):  
N. Musi ◽  
H. Yu ◽  
L.J. Goodyear
Keyword(s):  
Protein Kinase ◽  
Exercise Training ◽  
Metabolic Pathways ◽  
Acute Exercise ◽  
Glycogen Content ◽  
Glycogen Metabolism ◽  
Acid Oxidation ◽  
Ampk Activity ◽  
Energy Sensing ◽  
Amp Activated Protein Kinase

Physical exercise increases muscle glucose uptake, enhances insulin sensitivity and leads to fatty acid oxidation in muscle. The AMP-activated protein kinase (AMPK) is an energy-sensing enzyme that is strongly activated during muscle contraction due to acute decreases in ATP/AMP and phosphocreatine/creatine ratios. Accumulating evidence suggests that AMPK plays an important role in mediating these metabolic processes. Furthermore, AMPK has been implicated in regulating gene transcription and therefore may play a role in some of the cellular adaptations to training exercise. There is also evidence that changes in AMPK activity result in altered cellular glycogen content, suggesting that this enzyme regulates glycogen metabolism. Recent studies have shown that the magnitude of AMPK activation and associated metabolic responses are affected by factors such as glycogen content, exercise training and fibre type. In summary, AMPK regulates several metabolic pathways during acute exercise and modifies the expression of many genes involved in the adaptive changes to exercise training.

scholarly journals AMP-activated protein kinase: an ultrasensitive system for monitoring cellular energy charge

1999 ◽  
Vol 338 (3) ◽  
pp. 717-722 ◽  
Author(s):  
D. Grahame HARDIE ◽  
Ian P. SALT ◽  
Simon A. HAWLEY ◽  
Stephen P. DAVIES
Keyword(s):  
Protein Kinase ◽  
Energy Charge ◽  
Fold Increase ◽  
Maximal Activity ◽  
Hill Coefficient ◽  
Intact Cells ◽  
Cellular Energy ◽  
Critical Range ◽  
Kinase Cascade ◽  
Amp Activated Protein Kinase

The AMP-activated protein kinase cascade is activated by elevation of AMP and depression of ATP when cellular energy charge is compromised, leading to inhibition of anabolic pathways and activation of catabolic pathways. Here we show that the system responds in intact cells in an ultrasensitive manner over a critical range of nucleotide concentrations, in that only a 6-fold increase in activating nucleotide is required in order for the maximal activity of the kinase to progress from 10% to 90%, equivalent to a co-operative system with a Hill coefficient (h) of 2.5. Modelling suggests that this sensitivity arises from two features of the system: (i) AMP acts at multiple steps in the cascade (multistep sensitivity); and (ii) the upstream kinase is initially saturated with the downstream kinase (zero-order ultrasensitivity).

Metformin and phenformin activate AMP-activated protein kinase in the heart by increasing cytosolic AMP concentration

2007 ◽  
Vol 293 (1) ◽  
pp. H457-H466 ◽  
Author(s):  
Li Zhang ◽  
Huamei He ◽  
James A. Balschi
Keyword(s):  
Protein Kinase ◽  
Isolated Heart ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Cellular Energy ◽  
Rat Hearts ◽  
Energy Sensor ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase ◽  
Krebs Henseleit Buffer

AMP-activated protein kinase (AMPK) acts as a cellular energy sensor: it responds to an increase in AMP concentration ([AMP]) or the AMP-to-ATP ratio (AMP/ATP). Metformin and phenformin, which are biguanides, have been reported to increase AMPK activity without increasing AMP/ATP. This study tests the hypothesis that these biguanides increase AMPK activity in the heart by increasing cytosolic [AMP]. Groups of isolated rat hearts ( n = 5–7 each) were perfused with Krebs-Henseleit buffer with or without 0.2 mM phenformin or 10 mM metformin, and 31P-NMR-measured phosphocreatine, ATP, and intracellular pH were used to calculate cytosolic [AMP]. At various times, hearts were freeze-clamped and assayed for AMPK activity, phosphorylation of Thr172 on AMPK-α, and phosphorylation of Ser79 on acetyl-CoA carboxylase, an AMPK target. In hearts treated with phenformin for 18 min and then perfused for 20 min with Krebs-Henseleit buffer, [AMP] began to increase at 26 min and AMPK activity was elevated at 36 min. In hearts treated with metformin, [AMP] was increased at 50 min and AMPK activity, phosphorylated AMPK, and phosphorylated acetyl-CoA carboxylase were elevated at 61 min. In metformin-treated hearts, HPLC-measured total AMP content and total AMP/ATP did not increase. In summary, phenformin and metformin increase AMPK activity and phosphorylation in the isolated heart. The increase in AMPK activity was always preceded by and correlated with increased cytosolic [AMP]. Total AMP content and total AMP/ATP did not change. Cytosolic [AMP] reported metabolically active AMP, which triggered increased AMPK activity, but measures of total AMP did not.

scholarly journals Sumoylation of AMPKβ2 subunit enhances AMP-activated protein kinase activity

2013 ◽  
Vol 24 (11) ◽  
pp. 1801-1811 ◽  
Author(s):  
Teresa Rubio ◽  
Santiago Vernia ◽  
Pascual Sanz
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Catalytic Domain ◽  
Protein Kinase Activity ◽  
Energy Status ◽  
Regulatory Subunits ◽  
Cellular Energy ◽  
Sumo Ligase ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) is a sensor of cellular energy status. It is a heterotrimer composed of a catalytic α and two regulatory subunits (β and γ). AMPK activity is regulated allosterically by AMP and by the phosphorylation of residue Thr-172 within the catalytic domain of the AMPKα subunit by upstream kinases. We present evidence that the AMPKβ2 subunit may be posttranslationally modified by sumoylation. This process is carried out by the E3-small ubiquitin-like modifier (SUMO) ligase protein inhibitor of activated STAT PIASy, which modifies the AMPKβ2 subunit by the attachment of SUMO2 but not SUMO1 moieties. Of interest, AMPKβ1 is not a substrate for this modification. We also demonstrate that sumoylation of AMPKβ2 enhances the activity of the trimeric α2β2γ1 AMPK complex. In addition, our results indicate that sumoylation is antagonist and competes with the ubiquitination of the AMPKβ2 subunit. This adds a new layer of complexity to the regulation of the activity of the AMPK complex, since conditions that promote ubiquitination result in inactivation, whereas those that promote sumoylation result in the activation of the AMPK complex.

scholarly journals Role for AMP-activated protein kinase in glucose-stimulated insulin secretion and preproinsulin gene expression

2003 ◽  
Vol 371 (3) ◽  
pp. 761-774 ◽  
Author(s):  
Gabriela da SILVA XAVIER ◽  
Isabelle LECLERC ◽  
Aniko VARADI ◽  
Takashi TSUBOI ◽  
S. Kelly MOULE ◽  
...  
Keyword(s):  
Gene Expression ◽  
Insulin Secretion ◽  
Protein Kinase ◽  
Active Form ◽  
Dominant Negative ◽  
Β Cells ◽  
Dominant Negative Form ◽  
Ampk Activity ◽  
Glucose Stimulated Insulin Secretion ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) has recently been implicated in the control of preproinsulin gene expression in pancreatic islet β-cells [da Silva Xavier, Leclerc, Salt, Doiron, Hardie, Kahn and Rutter (2000) Proc. Natl. Acad. Sci. U.S.A. 97, 4023–4028]. Using pharmacological and molecular strategies to regulate AMPK activity in rat islets and clonal MIN6 β-cells, we show here that the effects of AMPK are exerted largely upstream of insulin release. Thus forced increases in AMPK activity achieved pharmacologically with 5-amino-4-imidazolecarboxamide riboside (AICAR), or by adenoviral overexpression of a truncated, constitutively active form of the enzyme (AMPKα1.T172D), blocked glucose-stimulated insulin secretion. In MIN6 cells, activation of AMPK suppressed glucose metabolism, as assessed by changes in total, cytosolic or mitochondrial [ATP] and NAD(P)H, and reduced increases in intracellular [Ca2+] caused by either glucose or tolbutamide. By contrast, inactivation of AMPK by expression of a dominant-negative form of the enzyme mutated in the catalytic site (AMPKα1.D157A) did not affect glucose-stimulated increases in [ATP], NAD(P)H or intracellular [Ca2+], but led to the unregulated release of insulin. These results indicate that inhibition of AMPK by glucose is essential for the activation of insulin secretion by the sugar, and may contribute to the transcriptional stimulation of the preproinsulin gene. Modulation of AMPK activity in the β-cell may thus represent a novel therapeutic strategy for the treatment of type 2 diabetes mellitus.

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.

AMP-activated protein kinase, super metabolic regulator

2003 ◽  
Vol 31 (1) ◽  
pp. 162-168 ◽  
Author(s):  
B.E. Kemp ◽  
D. Stapleton ◽  
D.J. Campbell ◽  
Z.-P. Chen ◽  
S. Murthy ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase ◽  
Metabolic Pathways ◽  
Energy Demand ◽  
Metabolic Stress ◽  
Demand And Supply ◽  
Stress Sensing ◽  
Amp Activated Protein Kinase ◽  
Rate Limiting

The AMP-activated protein kinase (AMPK) is a metabolic-stress-sensing protein kinase that regulates metabolism in response to energy demand and supply by directly phosphorylating rate-limiting enzymes in metabolic pathways as well as controlling gene expression.

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