Long-chain acyl-CoA esters inhibit phosphorylation of AMP-activated protein kinase at threonine-172 by LKB1/STRAD/MO25

2005 ◽  
Vol 288 (6) ◽  
pp. E1055-E1061 ◽  
Author(s):  
E. B. Taylor ◽  
W. J. Ellingson ◽  
J. D. Lamb ◽  
D. G. Chesser ◽  
W. W. Winder
Keyword(s):  
Protein Kinase ◽  
Kinase Activity ◽  
Energy Charge ◽  
Dependent Manner ◽  
Peptide Substrate ◽  
Concentration Dependent Manner ◽  
Ampk Signaling ◽  
Chain Acyl ◽  
Amp Activated Protein Kinase ◽  
Long Chain

Activation of the AMP-activated protein kinase (AMPK) results in acute changes in cellular metabolism and transcriptional events that make the cell more robust when encountering an energy challenge. AMPK is thought to be inhibited by glycogen, the major storage form of intracellular carbohydrate. We hypothesized that long-chain acyl-CoA esters (LCACEs) might also inhibit AMPK signaling. Cytosolic LCACEs are available for immediate transport and oxidation within the mitochondria and accordingly may be representative of the lipid energy charge of the cell. We found that LCACEs inhibited phosphorylation of AMPK by the recombinant AMPK kinase (AMPKK) LKB1/STRAD/MO25 in a concentration-dependent manner. Palmitoyl-CoA (PCoA) did not affect the activity of phosphothreonine-172 AMPK. PCoA potently inhibited AMPKK purified from liver. Conversely, PCoA stimulated the kinase activity of LKB1/STRAD/MO25 toward the peptide substrate LKB1tide. Octanoyl-CoA, palmitate, and palmitoylcarnitine did not inhibit AMPKK activity. Removal of AMP from the reaction mixture resulted in reduced AMPKK activity in the presence of PCoA. In conclusion, these results demonstrate that the AMPKK activity of LKB1/STRAD/MO25 is substrate specific and distinct from the kinase activity of LKB1/STRAD/MO25 toward the peptide substrate LKB1tide. They also demonstrate that LCACEs inhibit the AMPKK activity of LKB1/STRAD/MO25 in a specific manner with a dependence on both a long fatty chain and a CoA moiety. These results suggest that the AMPK signaling cascade may directly sense and respond to the lipid energy charge of the cell.

scholarly journals Complex effects of kinase localization revealed by compartment-specific regulation of protein kinase A activity

2021 ◽  
Author(s):  
Rebecca LaCroix ◽  
Benjamin Lin ◽  
Andre Levchenko
Keyword(s):  
Cell Migration ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Kinase Activity ◽  
Single Cells ◽  
Regulatory Subunit ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Specific Regulation ◽  
Kinase A

SummaryKinase activity in signaling networks frequently depends on regulatory subunits that can both inhibit activity by interacting with the catalytic subunits and target the kinase to distinct molecular partners and subcellular compartments. Here, using a new synthetic molecular interaction system, we show that translocation of a regulatory subunit of the protein kinase A (PKA-R) to the plasma membrane has a paradoxical effect on the membrane kinase activity. It can both enhance it at lower translocation levels, even in the absence of signaling inputs, and inhibit it at higher translocation levels, suggesting its role as a linker that can both couple and decouple signaling processes in a concentration-dependent manner. We further demonstrate that superposition of gradients of PKA-R abundance across single cells can control the directionality of cell migration, reversing it at high enough input levels. Thus complex in vivo patterns of PKA-R localization can drive complex phenotypes, including cell migration.

A Pharmacological Activator of AMP-Activated Protein Kinase Protects Hypoxic Neurons in a Concentration-Dependent Manner

2010 ◽  
Vol 35 (8) ◽  
pp. 1281-1289 ◽  
Author(s):  
Xiaolu Zhang ◽  
Rongkun Gao ◽  
Juan Li ◽  
Yanfei Qi ◽  
Xiuling Song ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Amp Activated Protein Kinase

scholarly journals Adenine Inhibits the Growth of Colon Cancer Cells via AMP-Activated Protein Kinase Mediated Autophagy

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Hsin-Wu Lai ◽  
James Cheng-Chung Wei ◽  
Hung-Chang Hung ◽  
Chun-Che Lin
Keyword(s):  
Colon Cancer ◽  
Protein Kinase ◽  
Cancer Cells ◽  
Underlying Mechanism ◽  
Dependent Manner ◽  
Colon Cancer Cells ◽  
Ampk Signaling ◽  
Anticancer Effects ◽  
Expression Of Genes ◽  
Amp Activated Protein Kinase

Background. Adenine is involved in a variety of cell biological processes and has been explored for pharmacological uses. Its therapeutic use for managing cancer is of great interest. In the present study, we investigated the anticancer effects of adenine and the underlying mechanism in colon cancer cells. Methods. Cell viability was measured using the MTT assay. Levels of phosphorylation and protein expression were determined using western blotting. qPCR was carried out to determine the changes in mRNA expression of genes of interest. Results. Adenine significantly inhibited the viability of colon cancer cells, HT29 and Caco-2 cells, in a dose-dependent manner. Adenine induced significant apoptosis in HT29 cells, whereas Caco-2 cells exhibited less apoptotic responses. The data showed that adenine activated AMP-activated protein kinase (AMPK) signaling contributing to autophagic cell death through mTOR in both colon cancer cell lines. Conclusions. Our findings suggest that adenine inhibits the growth of colon cancer cells. Anticancer activity of adenine in colon cancer cells is attributable to the activation of apoptotic signaling and in turn the AMPK/mTOR pathway. Adenine represents a natural compound with anticancer potency.

Characterization and partial purification of rat submandibular gland protein kinase C

1988 ◽  
Vol 66 (7) ◽  
pp. 683-690
Author(s):  
D. J. Pon ◽  
S. P. Lintlop ◽  
A. K. Sen
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Submandibular Gland ◽  
Kinase Activity ◽  
Partial Purification ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Kinase C ◽  
Membrane Bound ◽  
Rat Submandibular Gland

Membrane-bound protein kinase C of rat submandibular gland was characterized and the cytosolic kinase C of the tissue was partially purified. The membrane-bound kinase could be activated by Triton X-100 but not EGTA in the presence of both Ca2+ and phosphatidylserine (PS). The Km values for Ca2+ and PS were 150 μM and 5 μg, respectively. Addition of 10−6 M diacylglycerol resulted in an increased affinity of the kinase for Ca2+ (Km = 10 μM). Phorbol 12,13-dibutyrate activated the kinase in the absence of exogenous Ca2+ and PS, suggesting that adequate amounts of each activator are present in the membrane itself. Polymyxin B inhibited the stimulated kinase C activity in a concentration-dependent manner. This inhibition could be overcome by addition of PS. The cytosolic kinase was partially purified 133-fold by chromatography on columns of DEAE-Sephacel and S-300 Sephacryl. The total kinase activity increased with respect to the kinase activity measured in the starting material with column chromatography, suggesting that an inhibitor is present in the cytosolic fraction of the tissue.

scholarly journals 5′-AMP-activated protein kinase activity is elevated early during primary brain tumor development in the rat

2010 ◽  
Vol 128 (9) ◽  
pp. 2230-2239 ◽  
Author(s):  
Taichang Jang ◽  
Joy M. Calaoagan ◽  
Eunice Kwon ◽  
Steven Samuelsson ◽  
Lawrence Recht ◽  
...  
Keyword(s):  
Brain Tumor ◽  
Protein Kinase ◽  
Kinase Activity ◽  
Tumor Development ◽  
Primary Brain Tumor ◽  
Protein Kinase Activity ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase activity and glucose uptake in rat skeletal muscle

2001 ◽  
Vol 280 (5) ◽  
pp. E677-E684 ◽  
Author(s):  
Nicolas Musi ◽  
Tatsuya Hayashi ◽  
Nobuharu Fujii ◽  
Michael F. Hirshman ◽  
Lee A. Witters ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Muscle Contractions ◽  
Treadmill Running ◽  
Dependent Manner ◽  
Rat Skeletal Muscle ◽  
Amp Activated Protein Kinase ◽  
Dose Dependent

The AMP-activated protein kinase (AMPK) has been hypothesized to mediate contraction and 5-aminoimidazole-4-carboxamide 1-β-d-ribonucleoside (AICAR)-induced increases in glucose uptake in skeletal muscle. The purpose of the current study was to determine whether treadmill exercise and isolated muscle contractions in rat skeletal muscle increase the activity of the AMPKα1 and AMPKα2 catalytic subunits in a dose-dependent manner and to evaluate the effects of the putative AMPK inhibitors adenine 9-β-d-arabinofuranoside (ara-A), 8-bromo-AMP, and iodotubercidin on AMPK activity and 3- O-methyl-d-glucose (3-MG) uptake. There were dose-dependent increases in AMPKα2 activity and 3-MG uptake in rat epitrochlearis muscles with treadmill running exercise but no effect of exercise on AMPKα1 activity. Tetanic contractions of isolated epitrochlearis muscles in vitro significantly increased the activity of both AMPK isoforms in a dose-dependent manner and at a similar rate compared with increases in 3-MG uptake. In isolated muscles, the putative AMPK inhibitors ara-A, 8-bromo-AMP, and iodotubercidin fully inhibited AICAR-stimulated AMPKα2 activity and 3-MG uptake but had little effect on AMPKα1 activity. In contrast, these compounds had absent or minimal effects on contraction-stimulated AMPKα1 and -α2 activity and 3-MG uptake. Although the AMPKα1 and -α2 isoforms are activated during tetanic muscle contractions in vitro, in fast-glycolytic fibers, the activation of AMPKα2-containing complexes may be more important in regulating exercise-mediated skeletal muscle metabolism in vivo. Development of new compounds will be required to study contraction regulation of AMPK by pharmacological inhibition.

scholarly journals Myeloid deletion and therapeutic activation of AMP-activated protein kinase (AMPK) do not alter atherosclerosis in male or female mice

2020 ◽  
Author(s):  
Nicholas D. LeBlond ◽  
Peyman Ghorbani ◽  
Conor O’Dwyer ◽  
Nia Ambursley ◽  
Julia R. C. Nunes ◽  
...  
Keyword(s):  
Protein Kinase ◽  
First Generation ◽  
Western Diet ◽  
Daily Injection ◽  
Catalytic Subunits ◽  
Male And Female ◽  
Ampk Signaling ◽  
Female Mice ◽  
Amp Activated Protein Kinase ◽  
Progression Of Atherosclerosis

AbstractObjectiveThe dysregulation of myeloid-derived cell metabolism can drive atherosclerosis. AMP-activated protein kinase (AMPK) controls various aspects of macrophage dynamics and lipid homeostasis, which are important during atherogenesis.Approach and ResultsWe aimed to clarify the role of myeloid-specific AMPK signaling by using LysM-Cre to drive the deletion of both the α1 and α2 catalytic subunits (MacKO), in male and female mice made acutely atherosclerotic by PCSK9-AAV and Western diet-feeding. After 6 weeks of Western diet feeding, half received daily injection of either the AMPK activator, A-769662 or a vehicle control for a further 6 weeks. After 12 weeks, myeloid cell populations were not different between genotype or sex. Similarly, aortic sinus plaque size, lipid staining and necrotic area were not different in male and female MacKO mice compared to their littermate floxed controls. Moreover, therapeutic intervention with A-769662 had no effect. There were no differences in the amount of circulating total cholesterol or triglyceride, and only minor differences in the levels of inflammatory cytokines between groups. Finally, CD68+ area or markers of autophagy showed no effect of either lacking AMPK signaling or systemic AMPK activation.ConclusionsOur data suggest that while defined roles for each catalytic AMPK subunit have been identified, global deletion of myeloid AMPK signaling does not significantly impact atherosclerosis. Moreover, we show that intervention with the first-generation AMPK activator, A-769662, was not able to stem the progression of atherosclerosis.Highlights- The deletion of both catalytic subunits of AMPK in myeloid cells has no significant effect on the progression of atherosclerosis in either male or female mice- Therapeutic delivery of a first-generation AMPK activator (A-769662) for the last 6 weeks of 12-week study had no beneficial effect in either male or female mice- Studying total AMPK deletion may mask specific effects of each isoform and highlights the need for targeted disruption of AMPK phosphorylation sites via knock-in mutations, rather than the traditional “sledgehammer” knockout approach

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