scholarly journals Diurnal rhythm of phosphorylation of rat liver acetyl - CoA carboxylase by the AMP-activated protein kinase, demonstrated using freeze-clamping. Effects of high fat diets

1992 ◽  
Vol 203 (3) ◽  
pp. 615-623 ◽  
Author(s):  
Stephen P. DAVIES ◽  
David CARLING ◽  
Michael R. MUNDAY ◽  
D. Grahame HARDIE
Keyword(s):  
Protein Kinase ◽  
Rat Liver ◽  
Diurnal Rhythm ◽  
Acetyl Coa Carboxylase ◽  
High Fat ◽  
Acetyl Coa ◽  
High Fat Diets ◽  
Fat Diets ◽  
Amp Activated Protein Kinase

scholarly journals The short-term regulation of hepatic acetyl-CoA carboxylase during starvation and re-feeding in the rat

1991 ◽  
Vol 280 (3) ◽  
pp. 733-737 ◽  
Author(s):  
M R Munday ◽  
M R Milic ◽  
S Takhar ◽  
M J Holness ◽  
M C Sugden
Keyword(s):  
Protein Kinase ◽  
Rat Liver ◽  
Acetyl Coa Carboxylase ◽  
Short Term ◽  
Dependent Protein Kinase ◽  
Acetyl Coa ◽  
Plasma Insulin Concentration ◽  
Dependent Protein ◽  
Time Courses ◽  
Amp Activated Protein Kinase

Rapid inhibition of acetyl-CoA carboxylase (ACC) activity in rat liver in response to 6 h starvation and rapid re-activation in response to 2-6 h of re-feeding chow were shown to be due to changes in the expressed activity of existing enzyme. Decreases and increases in ACC concentration occurred at later stages of the transitions, i.e. 6-48 h starvation and 8-24 h re-feeding respectively. The decrease in expressed activity of ACC was due primarily to changes in its phosphorylation state, demonstrated by a significantly decreased Vmax. and significantly increased Ka for citrate of enzyme purified by avidin-Sepharose chromatography from 6 h- or 48 h-starved rats. These effects were totally reversed within 2-4 h of chow re-feeding. Changes in the activity of purified ACC closely correlated with reciprocal changes in the activity of AMP-activated protein kinase (AMP-PK) over the fed to starved to re-fed transition. Increases in the activity ratio of cyclic-AMP-dependent protein kinase in response to starvation lagged behind the increase in AMP-PK and the decrease in ACC activity. Changes in AMP-PK and ACC activities of rat liver closely correlated with changes in plasma insulin concentration in response to time courses of starvation and re-feeding.

Effect of phosphorylation by AMP-activated protein kinase on palmitoyl-CoA inhibition of skeletal muscle acetyl-CoA carboxylase

2005 ◽  
Vol 98 (4) ◽  
pp. 1221-1227 ◽  
Author(s):  
D. S. Rubink ◽  
W. W. Winder
Keyword(s):  
Skeletal Muscle ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Fatty Acid Oxidation ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Oxidation Rates ◽  
Malonyl Coa ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) has previously been demonstrated to phosphorylate and inactivate skeletal muscle acetyl-CoA carboxylase (ACC), the enzyme responsible for synthesis of malonyl-CoA, an inhibitor of carnitine palmitoyltransferase 1 and fatty acid oxidation. Contraction-induced activation of AMPK with subsequent phosphorylation/inactivation of ACC has been postulated to be responsible in part for the increase in fatty acid oxidation that occurs in muscle during exercise. These studies were designed to answer the question: Does phosphorylation of ACC by AMPK make palmitoyl-CoA a more effective inhibitor of ACC? Purified rat muscle ACC was subjected to phosphorylation by AMPK. Activity was determined on nonphosphorylated and phosphorylated ACC preparations at acetyl-CoA concentrations ranging from 2 to 500 μM and at palmitoyl-CoA concentrations ranging from 0 to 100 μM. Phosphorylation resulted in a significant decline in the substrate saturation curve at all palmitoyl-CoA concentrations. The inhibitor constant for palmitoyl-CoA inhibition of ACC was reduced from 1.7 ± 0.25 to 0.85 ± 0.13 μM as a consequence of phosphorylation. At 0.5 mM citrate, ACC activity was reduced to 13% of control values in response to the combination of phosphorylation and 10 μM palmitoyl-CoA. Skeletal muscle ACC is more potently inhibited by palmitoyl-CoA after having been phosphorylated by AMPK. This may contribute to low-muscle malonyl-CoA values and increasing fatty acid oxidation rates during long-term exercise when plasma fatty acid concentrations are elevated.

scholarly journals Glucagon Activates the AMP‐Activated Protein Kinase/Acetyl‐CoA Carboxylase Pathway in Adipocytes

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
I‐Chen Peng ◽  
Zhen Chen ◽  
Pang‐Hung Hsu ◽  
Mei‐I Su ◽  
Ming‐Daw Tsai ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Amp Activated Protein Kinase

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.

Protein Kinase C Is Activated and Diacylglycerol Is Elevated in Epidermal Cells from Sencar Mice Fed High Fat Diets

1992 ◽  
Vol 122 (12) ◽  
pp. 2322-2329 ◽  
Author(s):  
Myeon Choe ◽  
Edward S. Kris ◽  
Rajesh Luthra ◽  
James Copenhaver ◽  
Jill C. Pelling ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Epidermal Cells ◽  
High Fat ◽  
Kinase C ◽  
High Fat Diets ◽  
Fat Diets

Regulation of mammalian acetyl-CoA carboxylase

2002 ◽  
Vol 30 (6) ◽  
pp. 1059-1064 ◽  
Author(s):  
M. R. Munday
Keyword(s):  
Fatty Acid ◽  
Protein Kinase ◽  
Critical Role ◽  
Physiological Role ◽  
Acid Synthesis ◽  
Acid Oxidation ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Dependent Protein ◽  
Amp Activated Protein Kinase

Acetyl-CoA carboxylase (ACC) plays a critical role in the regulation of fatty acid metabolism and its two isoforms, ACCα and ACCβ, appear to have distinct functions in the control of fatty acid synthesis and fatty acid oxidation, respectively. They are regulated by similar short-term mechanisms of allosteric activation by citrate, and reversible phosphorylation and inactivation, and there is clearly interaction between these mechanisms. AMP-activated protein kinase is the important physiological ACC kinase for both isoforms and yet there is a potential physiological role for cAMP-dependent protein kinase in the hormonally mediated inactivation of ACCα, and phosphorylation of ACCβ in its unique N-terminus.

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