AMP-activated protein kinase and adenylate kinase prevent the ATP catastrophe and cytotoxic protein aggregation

2019 ◽  
Author(s):  
Masak Takaine ◽  
Hiromi Imamura ◽  
Satoshi Yoshida
Keyword(s):  
Protein Kinase ◽  
Protein Aggregation ◽  
Adenylate Kinase ◽  
Cytotoxic Protein ◽  
Atp Levels ◽  
Stochastic Fluctuations ◽  
Physiological Relevance ◽  
Endogenous Proteins ◽  
Amp Activated Protein Kinase ◽  
Yeast Mutants

ABSTRACTATP is the main source of chemical energy in all life and is maintained at several millimolar in eukaryotic cells. However, the mechanisms responsible for and physiological relevance of this high and stable concentration of ATP remain unclear. We herein demonstrate that AMP-activated protein kinase (AMPK) and adenylate kinase (ADK) cooperate to maintain cellular ATP levels regardless of glucose concentrations. Single cell imaging of ATP-reduced yeast mutants revealed that ATP concentrations in these mutants underwent stochastic and transient depletion of ATP repeatedly, which induced the cytotoxic aggregation of endogenous proteins and pathogenic proteins, such as huntingtin and α-synuclein. Moreover, pharmacological elevations in ATP levels in an ATP-reduced mutant prevented the accumulation of α-synuclein aggregates and its cytotoxicity. The removal of cytotoxic aggregates depended on proteasomes, and proteasomal activity cooperated with AMPK or ADK to resist proteotoxic stresses. The present results provide the first evidence to show that cellular ATP homeostasis ensures proteostasis and revealed that stochastic fluctuations in cellular ATP concentrations contribute to cytotoxic protein aggregation, implying that AMPK and ADK are important factors that prevent proteinopathies, such as neurodegenerative diseases.

AMPK activation with AICAR provokes an acute fall in plasma [K+]

2008 ◽  
Vol 294 (1) ◽  
pp. C126-C135 ◽  
Author(s):  
Dan Zheng ◽  
Anjana Perianayagam ◽  
Donna H. Lee ◽  
M. Douglas Brannan ◽  
Li E. Yang ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Infusion Rate ◽  
Extracellular Fluid ◽  
Ampk Activation ◽  
Conscious Rats ◽  
Significant Fall ◽  
Ampk Phosphorylation ◽  
Atp Levels ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK), activated by an increase in intracellular AMP-to-ATP ratio, stimulates pathways that can restore ATP levels. We tested the hypothesis that AMPK activation influences extracellular fluid (ECF) K+ homeostasis. In conscious rats, AMPK was activated with 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) infusion: 38.4 mg/kg bolus then 4 mg·kg−1·min−1 infusion. Plasma [K+] and [glucose] both dropped at 1 h of AICAR infusion and [K+] dropped to 3.3 ± 0.04 mM by 3 h, linearly related to the increase in muscle AMPK phosphorylation. AICAR treatment did not increase urinary K+ excretion. AICAR lowered [K+] whether plasma [K+] was chronically elevated or lowered. The K+ infusion rate needed to maintain baseline plasma [K+] reached 15.7 ± 1.3 μmol K+·kg−1·min−1 between 120 and 180 min AICAR infusion. In mice expressing a dominant inhibitory form of AMPK in the muscle (Tg-KD1), baseline [K+] was not different from controls (4.2 ± 0.1 mM), but the fall in plasma [K+] in response to AICAR (0.25 g/kg) was blunted: [K+] fell to 3.6 ± 0.1 in controls and to 3.9 ± 0.1 mM in Tg-KD1, suggesting that ECF K+ redistributes, at least in part, to muscle ICF. In summary, these findings illustrate that activation of AMPK activity with AICAR provokes a significant fall in plasma [K+] and suggest a novel mechanism for redistributing K+ from ECF to ICF.

Physiological modulation of CFTR activity by AMP-activated protein kinase in polarized T84 cells

2003 ◽  
Vol 284 (5) ◽  
pp. C1297-C1308 ◽  
Author(s):  
Kenneth R. Hallows ◽  
Gary P. Kobinger ◽  
James M. Wilson ◽  
Lee A. Witters ◽  
J. Kevin Foskett
Keyword(s):  
Protein Kinase ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Physiological Role ◽  
Dominant Negative ◽  
T84 Cells ◽  
Physiological Relevance ◽  
Polarized Epithelia ◽  
Ampk Activity ◽  
Amp Activated Protein Kinase

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-activated, ATP-gated Cl− channel and cellular conductance regulator, but the detailed mechanisms of CFTR regulation and its regulation of other transport proteins remain obscure. We previously identified the metabolic sensor AMP-activated protein kinase (AMPK) as a novel protein interacting with CFTR and found that AMPK phosphorylated CFTR and inhibited CFTR-dependent whole cell conductances when coexpressed with CFTR in Xenopus oocytes. To address the physiological relevance of the CFTR-AMPK interaction, we have now studied polarized epithelia and have evaluated the localization of endogenous AMPK and CFTR and measured CFTR activity with modulation of AMPK activity. By immunofluorescent imaging, AMPK and CFTR share an overlapping apical distribution in several rat epithelial tissues, including nasopharynx, submandibular gland, pancreas, and ileum. CFTR-dependent short-circuit currents ( Isc ) were measured in polarized T84 cells grown on permeable supports, and several independent methods were used to modulate endogenous AMPK activity. Activation of endogenous AMPK with the cell-permeant adenosine analog 5-amino-4-imidazolecarboxamide-1-β-d-ribofuranoside (AICAR) inhibited forskolin-stimulated CFTR-dependent I sc in nonpermeabilized monolayers and monolayers with nystatin permeabilization of the basolateral membrane. Raising intracellular AMP concentration in monolayers with basolateral membranes permeabilized with α-toxin also inhibited CFTR, an effect that was unrelated to adenosine receptors. Finally, overexpression of a kinase-dead mutant AMPK-α1 subunit (α1-K45R) enhanced forskolin-stimulated I sc in polarized T84 monolayers, consistent with a dominant-negative reduction in the inhibition of CFTR by endogenous AMPK. These results indicate that AMPK plays a physiological role in modulating CFTR activity in polarized epithelia and suggest a novel paradigm for the coupling of ion transport to cellular metabolism.

Activity of LKB1 and AMPK-related kinases in skeletal muscle: effects of contraction, phenformin, and AICAR

2004 ◽  
Vol 287 (2) ◽  
pp. E310-E317 ◽  
Author(s):  
Kei Sakamoto ◽  
Olga Göransson ◽  
D. Grahame Hardie ◽  
Dario R. Alessi
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Muscle Contraction ◽  
Cultured Cells ◽  
Muscle Fiber Types ◽  
Fiber Types ◽  
Physiological Relevance ◽  
Lkb1 Tumor Suppressor ◽  
Sciatic Nerve Stimulation ◽  
Amp Activated Protein Kinase

Activation of AMP-activated protein kinase (AMPK) by exercise and metformin is beneficial for the treatment of type 2 diabetes. We recently found that, in cultured cells, the LKB1 tumor suppressor protein kinase activates AMPK in response to the metformin analog phenformin and the AMP mimetic drug 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside (AICAR). We have also reported that LKB1 activates 11 other AMPK-related kinases. The activity of LKB1 or the AMPK-related kinases has not previously been studied in a tissue with physiological relevance to diabetes. In this study, we have investigated whether contraction, phenformin, and AICAR influence LKB1 and AMPK-related kinase activity in rat skeletal muscle. Contraction in situ, induced via sciatic nerve stimulation, significantly increased AMPKα2 activity and phosphorylation in multiple muscle fiber types without affecting LKB1 activity. Treatment of isolated skeletal muscle with phenformin or AICAR stimulated the phosphorylation and activation of AMPKα1 and AMPKα2 without altering LKB1 activity. Contraction, phenformin, or AICAR did not significantly increase activities or expression of the AMPK-related kinases QSK, QIK, MARK2/3, and MARK4 in skeletal muscle. The results of this study suggest that muscle contraction, phenformin, or AICAR activates AMPK by a mechanism that does not involve direct activation of LKB1. They also suggest that the effects of excercise, phenformin, and AICAR on metabolic processes in muscle may be mediated through activation of AMPK rather than activation of LKB1 or the AMPK-related kinases.

A molecular approach to the concerted action of kinases involved in energy homoeostasis

2003 ◽  
Vol 31 (1) ◽  
pp. 169-174 ◽  
Author(s):  
D. Neumann ◽  
U. Schlattner ◽  
T. Wallimann
Keyword(s):  
Protein Kinase ◽  
Adenylate Kinase ◽  
Energy Production ◽  
Molecular Level ◽  
Concerted Action ◽  
A Cell ◽  
Response To Stress ◽  
Downstream Processes ◽  
Amp Activated Protein Kinase

One of the most important duties of a cell is energy homoeostasis. Several kinases, including AMP-activated protein kinase (AMPK), creatine kinase and adenylate kinase, are involved in the immediate response to stress, resulting in energy depletion. Here, we present our view of events preceding the downstream processes mediated by AMPK and leading to reduced energy expenditure and increased energy production. Unfortunately, AMPK is very poorly defined at the molecular level. Thus a procedure for production of AMPK in milligram amounts is presented which will greatly facilitate the functional and structural characterization of this protein kinase.

Activation of glucose transport and AMP-activated protein kinase during muscle contraction in adenylate kinase-1 knockout mice

2008 ◽  
Vol 192 (3) ◽  
pp. 413-420 ◽  
Author(s):  
S. -J. Zhang ◽  
M. E. Sandström ◽  
J. Aydin ◽  
H. Westerblad ◽  
B. Wieringa ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Muscle Contraction ◽  
Glucose Transport ◽  
Knockout Mice ◽  
Adenylate Kinase ◽  
Amp Activated Protein Kinase ◽  
Adenylate Kinase 1

scholarly journals Metabolic and hormonal interactions between muscle and adipose tissue

2004 ◽  
Vol 63 (2) ◽  
pp. 381-385 ◽  
Author(s):  
Eva Tomas ◽  
Meghan Kelly ◽  
Xiaoqin Xiang ◽  
Tsu-Shuen Tsao ◽  
Charlotte Keller ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Adipose Tissue ◽  
Protein Kinase ◽  
Leptin Receptor ◽  
Acid Oxidation ◽  
Peripheral Tissues ◽  
Endocrine Organ ◽  
Energy Needs ◽  
Physiological Relevance ◽  
Amp Activated Protein Kinase

From the perspective of a muscle physiologist, adipose tissue has long been perceived predominantly as a fuel reservoir that provides muscle and other tissues with NEFA when exogenous nutrients are insufficient for their energy needs. Recently, studies have established that adipose tissue is also an endocrine organ. Among the hormones it releases are adiponectin and leptin, both of which can activate AMP-activated protein kinase and increase fatty acid oxidation in skeletal muscle and probably other tissues. Deficiencies of leptin or leptin receptor, adiponectin and IL-6 are associated with obesity, insulin resistance and a propensity to type 2 diabetes. In addition, a lack of adiponectin has been linked to atherosclerosis. Whether this pathology reflects a deficient activation of AMP-activated protein kinase in peripheral tissues remains to be determined. Finally, recent studies have suggested that skeletal muscle may also function as an endocrine organ when it releases the cytokine IL-6 into the circulation during sustained exercise. Interestingly, one of the apparent effects of IL-6 is to stimulate lipolysis, causing the release of NEFA from the adipocyte. Thus, hormonal communications exist between the adipocyte and muscle that could enable them to talk to each other. The physiological relevance of this cross talk clearly warrants further study.

Abstract 458: Novel Interactions With AMP-activated Protein Kinase Identified by Promiscuous Biotin Ligase Assay

2016 ◽  
Vol 119 (suppl_1) ◽  
Author(s):  
Yulia Lipovka ◽  
John P Konhilas
Keyword(s):  
Protein Kinase ◽  
Estrogen Receptors ◽  
Catalytic Subunit ◽  
Neonatal Rat ◽  
Energy Regulation ◽  
Rat Cardiomyocytes ◽  
Biotin Ligase ◽  
Upstream Kinase ◽  
Endogenous Proteins ◽  
Amp Activated Protein Kinase

Estrogen is positioned to play a unique role in cardiovascular disease (CVD) since it can respond to environmental, genetic and non-genetic cues to impact gene expression and cellular signaling. Recently AMP-activated protein kinase (AMPK) has been identified as an important modulator of CVD. We propose that AMPK represents a nodal point for estrogen-dependent modulation of CVD. Our preliminary studies in a non-muscle cell line demonstrate that estrogen (E2) regulates AMPK activity predominantly through Estrogen Receptor alpha (ERα). In addition, both classical estrogen receptors (ERα and ERβ) bind to the α-catalytic subunit of AMPK, and the upstream kinase complex LKB1 is required for AMPK activation after E2 stimulation. The next step is to translate these findings into the cardiac system. In order to do that, we validated a novel technology to screen for interactions based on a promiscuous biotin ligase from E. coli . We created vectors containing our protein of interest, AMPK and/or the upstream kinase complex, LKB1, fused to the biotin ligase. After infecting Neonatal Rat Cardiomyocytes (NRCM) with viruses expressing those constructs, we added biotin to the cells, allowing biotinylation of proximal endogenous proteins; following biotin-affinity capture and western blot analysis. We show that estrogen receptors bind both to the α-catalytic subunit of AMPK, and the upstream kinase complex LKB1 in NRCM. Co-immunoprecipitation of endogenous proteins confirmed those interactions. In addition, we characterized a novel interaction between AMPK and the cytoskeletal protein, vinculin. Previous studies in our lab showed that AMPK is a modulator of myofilament function, and that the estrogen receptors associate with myofilament proteins. These, along with the findings detailed above open a new perspective on cardiac energy regulation.

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