scholarly journals The regulation and function of the NUAK family

2013 ◽  
Vol 51 (2) ◽  
pp. R15-R22 ◽  
Author(s):  
Xianglan Sun ◽  
Ling Gao ◽  
Hung-Yu Chien ◽  
Wan-Chun Li ◽  
Jiajun Zhao
Keyword(s):  
Protein Kinase ◽  
Structural Organization ◽  
Energy Homeostasis ◽  
Catalytic Domain ◽  
Whole Body ◽  
Upstream Kinase ◽  
Liver Kinase B1 ◽  
And Function ◽  
Amp Activated Protein Kinase ◽  
Body Energy

AMP-activated protein kinase (AMPK) is a critical regulator of cellular and whole-body energy homeostasis. Twelve AMPK-related kinases (ARKs; BRSK1, BRSK2, NUAK1, NUAK2, QIK, QSK, SIK, MARK1, MARK2, MARK3, MARK4, and MELK) have been identified recently. These kinases show a similar structural organization, including an N-terminal catalytic domain, followed by a ubiquitin-associated domain and a C-terminal spacer sequence, which in some cases also contains a kinase-associated domain 1. Eleven of the ARKs are phosphorylated and activated by the master upstream kinase liver kinase B1. However, most of these ARKs are largely unknown, and the NUAK family seems to have different regulations and functions. This review contains a brief discussion of the NUAK family including the specific characteristics of NUAK1 and NUAK2.

Exercise and MEF2–HDAC interactions

2007 ◽  
Vol 32 (5) ◽  
pp. 852-856 ◽  
Author(s):  
Sean L. McGee
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Nuclear Export ◽  
Energy Homeostasis ◽  
Whole Body ◽  
Positive Health ◽  
Exercise Induced ◽  
Amp Activated Protein Kinase ◽  
Body Energy ◽  
Skeletal Muscle Adaptations

Exercise increases the metabolic capacity of skeletal muscle, which improves whole-body energy homeostasis and contributes to the positive health benefits of exercise. This is, in part, mediated by increases in the expression of a number of metabolic enzymes, regulated largely at the level of transcription. At a molecular level, many of these genes are regulated by the class II histone deacetylase (HDAC) family of transcriptional repressors, in particular HDAC5, through their interaction with myocyte enhancer factor 2 transcription factors. HDAC5 kinases, including 5′-AMP-activated protein kinase and protein kinase D, appear to regulate skeletal muscle metabolic gene transcription by inactivating HDAC5 and inducing HDAC5 nuclear export. These mechanisms appear to participate in exercise-induced gene expression and could be important for skeletal muscle adaptations to exercise.

scholarly journals Skeletal muscle AMP-activated protein kinase γ1H151R overexpression enhances whole body energy homeostasis and insulin sensitivity

2015 ◽  
Vol 309 (7) ◽  
pp. E679-E690 ◽  
Author(s):  
Milena Schönke ◽  
Martin G. Myers ◽  
Juleen R. Zierath ◽  
Marie Björnholm
Keyword(s):  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Protein Kinase ◽  
Transgenic Mice ◽  
Energy Homeostasis ◽  
Whole Body ◽  
Α Subunit ◽  
Peripheral Tissues ◽  
Amp Activated Protein Kinase ◽  
Body Energy

AMP-activated protein kinase (AMPK) is a major sensor of energy homeostasis and stimulates ATP-generating processes such as lipid oxidation and glycolysis in peripheral tissues. The heterotrimeric enzyme consists of a catalytic α-subunit, a β-subunit that is important for enzyme activity, and a noncatalytic γ-subunit that binds AMP and activates the AMPK complex. We generated a skeletal muscle Cre-inducible transgenic mouse model expressing a mutant γ1-subunit (AMPKγ1H151R), resulting in chronic AMPK activation. The expression of the predominant AMPKγ3 isoform in skeletal muscle was reduced in extensor digitorum longus (EDL) muscle (81–83%) of AMPKγ1H151R transgenic mice, whereas the abundance and phosphorylation of the AMPK target acetyl-CoA carboxylase was increased in tibialis anterior muscle. Glycogen content was increased 10-fold in gastrocnemius muscle. Whole body carbohydrate oxidation was increased by 11%, and whereas glucose tolerance was unaffected, insulin sensitivity was increased in AMPKγ1H151R transgenic mice. Furthermore, perigonadal white adipose tissue mass and serum leptin were reduced in female AMPKγ1H151R transgenic mice by 38 and 51% respectively. Conversely, in male AMPKγ1H151R transgenic mice, food intake was increased (14%), but body weight and body composition were unaltered, presumably because of increased energy expenditure. In conclusion, transgenic activation of skeletal muscle AMPKγ1 in this model plays an important sex-specific role in skeletal muscle metabolism and whole body energy homeostasis.

Hypothalamic AMP-activated protein kinase as a mediator of whole body energy balance

2011 ◽  
Vol 12 (3) ◽  
pp. 127-140 ◽  
Author(s):  
Pablo Blanco Martínez de Morentin ◽  
Carmen R. González ◽  
Asisk K. Saha ◽  
Luís Martins ◽  
Carlos Diéguez ◽  
...  
Keyword(s):  
Energy Balance ◽  
Protein Kinase ◽  
Whole Body ◽  
Amp Activated Protein Kinase ◽  
Body Energy

scholarly journals AMPK: Regulating Energy Balance at the Cellular and Whole Body Levels

Physiology ◽  
2014 ◽  
Vol 29 (2) ◽  
pp. 99-107 ◽  
Author(s):  
D. Grahame Hardie ◽  
Michael L. J. Ashford
Keyword(s):  
Energy Balance ◽  
Protein Kinase ◽  
Energy Homeostasis ◽  
Adenine Nucleotide ◽  
Cellular Level ◽  
Whole Body ◽  
Balancing Energy ◽  
Body Level ◽  
Multicellular Organisms ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase appears to have evolved in single-celled eukaryotes as an adenine nucleotide sensor that maintains energy homeostasis at the cellular level. However, during evolution of more complex multicellular organisms, the system has adapted to interact with hormones so that it also plays a key role in balancing energy intake and expenditure at the whole body level.

Allosteric regulation of AMP-activated protein kinase by adenylate nucleotides and small-molecule drugs

2019 ◽  
Vol 47 (2) ◽  
pp. 733-741 ◽  
Author(s):  
Ana Laura de Souza Almeida Matos ◽  
Jonathan S. Oakhill ◽  
José Moreira ◽  
Kim Loh ◽  
Sandra Galic ◽  
...  
Keyword(s):  
Energy Balance ◽  
Protein Kinase ◽  
Small Molecule ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Cellular Level ◽  
Whole Body ◽  
Allosteric Activation ◽  
Small Molecule Drugs ◽  
Body Energy

Abstract The AMP (adenosine 5′-monophosphate)-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis that co-ordinates metabolic processes to ensure energy supply meets demand. At the cellular level, AMPK is activated by metabolic stresses that increase AMP or adenosine 5′-diphosphate (ADP) coupled with falling adenosine 5′-triphosphate (ATP) and acts to restore energy balance by choreographing a shift in metabolism in favour of energy-producing catabolic pathways while inhibiting non-essential anabolic processes. AMPK also regulates systemic energy balance and is activated by hormones and nutritional signals in the hypothalamus to control appetite and body weight. Failure to maintain energy balance plays an important role in chronic diseases such as obesity, type 2 diabetes and inflammatory disorders, which has prompted a major drive to develop pharmacological activators of AMPK. An array of small-molecule allosteric activators has now been developed, several of which can activate AMPK by direct allosteric activation, independently of Thr172 phosphorylation, which was previously regarded as indispensable for AMPK activity. In this review, we summarise the state-of-the-art regarding our understanding of the molecular mechanisms that govern direct allosteric activation of AMPK by adenylate nucleotides and small-molecule drugs.

scholarly journals The relevance of AMP-activated protein kinase in insulin-secreting β cells: a potential target for improving β cell function?

2019 ◽  
Vol 75 (4) ◽  
pp. 423-432 ◽  
Author(s):  
Tomasz Szkudelski ◽  
Katarzyna Szkudelska
Keyword(s):  
Protein Kinase ◽  
Energy Homeostasis ◽  
Cell Function ◽  
Islet Cells ◽  
Regulation Of Gene Expression ◽  
Glucose Deprivation ◽  
Whole Body ◽  
Β Cells ◽  
Amp Activated Protein Kinase

Abstract AMP-activated protein kinase (AMPK) is present in different kinds of metabolically active cells. AMPK is an important intracellular energy sensor and plays a relevant role in whole-body energy homeostasis. AMPK is activated, among others, in response to glucose deprivation, caloric restriction and increased physical activity. Upon activation, AMPK affects metabolic pathways leading to increased formation of ATP and simultaneously reducing ATP-consuming processes. AMPK is also expressed in pancreatic β cells and is largely regulated by glucose, which is the main physiological stimulator of insulin secretion. Results of in vitro studies clearly show that glucose-induced insulin release is associated with a concomitant inhibition of AMPK in β cells. However, pharmacological activation of AMPK significantly potentiates the insulin-secretory response of β cells to glucose and to some other stimuli. This effect is primarily due to increased intracellular calcium concentrations. AMPK is also involved in the regulation of gene expression and may protect β cells against glucolipotoxic conditions. It was shown that in pancreatic islets of humans with type 2 diabetes, AMPK is downregulated. Moreover, studies with animal models demonstrated impaired link between glucose and AMPK activity in pancreatic islet cells. These data suggest that AMPK may be a target for compounds improving the functionality of β cells. However, more studies are required to better elucidate the relevance of AMPK in the (patho)physiology of the insulin-secreting cells.

AMP-activated protein kinase and the metabolic syndrome

2005 ◽  
Vol 33 (2) ◽  
pp. 362-366 ◽  
Author(s):  
L.G.D. Fryer ◽  
D. Carling
Keyword(s):  
Protein Kinase ◽  
Glycogen Metabolism ◽  
Energy Utilization ◽  
Whole Body ◽  
Acid Oxidation ◽  
Type Ii ◽  
Glucose Levels ◽  
The Metabolic Syndrome ◽  
Amp Activated Protein Kinase ◽  
Body Energy

The occurrence of Type II (non-insulin-dependent) diabetes and obesity and their associated morbidities continue to increase and they are rapidly reaching epidemic proportions. AMPK (AMP-activated protein kinase) was initially thought of as an intracellular ‘fuel gauge’ responding to a decrease in the level of ATP by increasing energy production and decreasing energy utilization. Recent studies have shown that AMPK plays a role in controlling the whole body energy homoeostasis, including the regulation of plasma glucose levels, fatty acid oxidation and glycogen metabolism. In addition to its effects on the periphery, AMPK has been found to play a key role in the control of food intake through its regulation by hormones, including leptin, within the hypothalamus. The control of AMPK activity, therefore, provides an attractive target for therapeutic intervention in metabolic disorders such as obesity and Type II diabetes. Indeed, a number of physiological and pharmacological factors that are beneficial in these disorders have been shown to act, at least in part, through the activation of AMPK.

scholarly journals Is TAK1 a Direct Upstream Kinase of AMPK?

2018 ◽  
Vol 19 (8) ◽  
pp. 2412 ◽  
Author(s):  
Dietbert Neumann
Keyword(s):  
Protein Kinase ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Dependent Protein Kinase ◽  
Open Questions ◽  
Upstream Kinase ◽  
Liver Kinase B1 ◽  
Dependent Protein ◽  
Amp Activated Protein Kinase ◽  
Protein Kinase Kinase

Alongside Liver kinase B1 (LKB1) and Ca2+/Calmodulin-dependent protein kinase kinase 2 (CaMKK2), Transforming growth factor-β (TGF-β)-activated kinase 1 (TAK1) has been suggested as a direct upstream kinase of AMP-activated protein kinase (AMPK). Several subsequent studies have reported on the TAK1-AMPK relationship, but the interpretation of the respective data has led to conflicting views. Therefore, to date the acceptance of TAK1 as a genuine AMPK kinase is lagging behind. This review provides with argumentation, whether or not TAK1 functions as a direct upstream kinase of AMPK. Several specific open questions that may have precluded the consensus are discussed based on available data. In brief, TAK1 can function as direct AMPK upstream kinase in specific contexts and in response to a subset of TAK1 activating stimuli. Further research is needed to define the intricate signals that are conditional for TAK1 to phosphorylate and activate AMPKα at T172.

scholarly journals A-769662 inhibits adipocyte glucose uptake in an AMPK-independent manner

2021 ◽  
Vol 478 (3) ◽  
pp. 633-646
Author(s):  
Franziska Kopietz ◽  
Yazeed Alshuweishi ◽  
Silvia Bijland ◽  
Fatmah Alghamdi ◽  
Eva Degerman ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Energy Homeostasis ◽  
Inhibitory Effect ◽  
Whole Body ◽  
Ampk Activation ◽  
Independent Manner ◽  
Amp Activated Protein Kinase ◽  
Body Energy ◽  
Site Binding

Activation of AMP-activated protein kinase (AMPK) is considered a valid strategy for the treatment of type 2 diabetes. However, despite the importance of adipose tissue for whole-body energy homeostasis, the effect of AMPK activation in adipocytes has only been studied to a limited extent and mainly with the AMP-mimetic 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR), which has limited specificity. The aim of this study was to evaluate the effect of the allosteric AMPK activators A-769662 and 991 on glucose uptake in adipocytes. For this purpose, primary rat or human adipocytes, and cultured 3T3-L1 adipocytes, were treated with either of the allosteric activators, or AICAR, and basal and insulin-stimulated glucose uptake was assessed. Additionally, the effect of AMPK activators on insulin-stimulated phosphorylation of Akt and Akt substrate of 160 kDa was assessed. Furthermore, primary adipocytes from ADaM site binding drug-resistant AMPKβ1 S108A knock-in mice were employed to investigate the specificity of the drugs for the observed effects. Our results show that insulin-stimulated adipocyte glucose uptake was significantly reduced by A-769662 but not 991, yet neither activator had any clear effects on basal or insulin-stimulated Akt/AS160 signaling. The use of AMPKβ1 S108A mutant-expressing adipocytes revealed that the observed inhibition of glucose uptake by A-769662 is most likely AMPK-independent, a finding which is supported by the rapid inhibitory effect A-769662 exerts on glucose uptake in 3T3-L1 adipocytes. These data suggest that AMPK activation per se does not inhibit glucose uptake in adipocytes and that the effects of AICAR and A-769662 are AMPK-independent.

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