scholarly journals The protein phosphatases responsible for dephosphorylation of hormone-sensitive lipase in isolated rat adipocytes

1993 ◽  
Vol 295 (2) ◽  
pp. 531-535 ◽  
Author(s):  
S L Wood ◽  
N Emmison ◽  
A C Borthwick ◽  
S J Yeaman
Keyword(s):  
Adipose Tissue ◽  
Phosphatase Activity ◽  
Protein Phosphatases ◽  
Total Activity ◽  
Hormone Sensitive Lipase ◽  
Rat Adipocytes ◽  
Hormone Sensitive ◽  
Total Phosphatase Activity ◽  
Isolated Rat

The levels of the cytosolic serine/threonine protein phosphatases (PP) in rat adipocyte extracts have been determined, by using both reference substrates and hormone-sensitive lipase (HSL) as substrates. Adipocytes contain significant levels of both PP1 and 2A (1.6 and 2.0 m-units/ml of packed cells respectively), with lower levels of PP2C and virtually no PP2B activity. PP2A and 2C exhibit similar degrees of activity against HSL phosphorylated at site 1, together accounting for 92% of the total. In contrast, site 2 is dephosphorylated predominantly by PP2A (over 50% of total activity), whereas PP1 and PP2C contribute approx. 20% and 30% respectively to the total phosphatase activity against that site. Total phosphatase activity in the adipocyte extracts was 2-3-fold higher against site 2 than against site 1. The possible significance of these findings to the regulation of HSL activity in adipose tissue in vivo is discussed.

scholarly journals AMPK Phosphorylates Desnutrin/ATGL and Hormone-Sensitive Lipase To Regulate Lipolysis and Fatty Acid Oxidation within Adipose Tissue

2016 ◽  
Vol 36 (14) ◽  
pp. 1961-1976 ◽  
Author(s):  
Sun-Joong Kim ◽  
Tianyi Tang ◽  
Marcia Abbott ◽  
Jose A. Viscarra ◽  
Yuhui Wang ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Protein Kinase ◽  
Hydrolase Activity ◽  
Hormone Sensitive Lipase ◽  
Acid Oxidation ◽  
Peroxisome Proliferator ◽  
Hormone Sensitive

The role of AMP-activated protein kinase (AMPK) in promoting fatty acid (FA) oxidation in various tissues, such as liver and muscle, has been well understood. However, the role of AMPK in lipolysis and FA metabolism in adipose tissue has been controversial. To investigate the role of AMPK in the regulation of adipose lipolysisin vivo, we generated mice with adipose-tissue-specific knockout of both the α1 and α2 catalytic subunits of AMPK (AMPK-ASKO mice) by using aP2-Cre and adiponectin-Cre. Both models of AMPK-ASKO ablation show no changes in desnutrin/ATGL levels but have defective phosphorylation of desnutrin/ATGL at S406 to decrease its triacylglycerol (TAG) hydrolase activity, lowering basal lipolysis in adipose tissue. These mice also show defective phosphorylation of hormone-sensitive lipase (HSL) at S565, with higher phosphorylation at protein kinase A sites S563 and S660, increasing its hydrolase activity and isoproterenol-stimulated lipolysis. With higher overall adipose lipolysis, both models of AMPK-ASKO mice are lean, having smaller adipocytes with lower TAG and higher intracellular free-FA levels. Moreover, FAs from higher lipolysis activate peroxisome proliferator-activated receptor delta to induce FA oxidative genes and increase FA oxidation and energy expenditure. Overall, for the first time, we providein vivoevidence of the role of AMPK in the phosphorylation and regulation of desnutrin/ATGL and HSL and thus adipose lipolysis.

scholarly journals Central melanocortin stimulation increases phosphorylated perilipin A and hormone-sensitive lipase in adipose tissues

2010 ◽  
Vol 299 (1) ◽  
pp. R140-R149 ◽  
Author(s):  
Y. B. Shrestha ◽  
C. H. Vaughan ◽  
B. J. Smith ◽  
C. K. Song ◽  
D. J. Baro ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Sympathetic Nerves ◽  
Hormone Sensitive Lipase ◽  
Interscapular Brown Adipose Tissue ◽  
Brown Adipose ◽  
Perilipin A ◽  
Hormone Sensitive

Norepinephrine (NE) released from the sympathetic nerves innervating white adipose tissue (WAT) is the principal initiator of lipolysis in mammals. Central WAT sympathetic outflow neurons express melanocortin 4-receptor (MC4-R) mRNA. Single central injection of melanotan II (MTII; MC3/4-R agonist) nonuniformly increases WAT NE turnover (NETO), increases interscapular brown adipose tissue (IBAT) NETO, and increases the circulating lipolytic products glycerol and free fatty acid. The WAT pads that contributed to this lipolysis were inferred from the increases in NETO. Because phosphorylation of perilipin A (p-perilipin A) and hormone-sensitive lipase are necessary for NE-triggered lipolysis, we tested whether MTII would increase these intracellular markers of lipolysis. Male Siberian hamsters received a single 3rd ventricular injection of MTII or saline. Trunk blood was collected at 0.5, 1.0, and 2.0 h postinjection from excised inguinal, retroperitoneal, and epididymal WAT (IWAT, RWAT, and EWAT, respectively) and IBAT pads. MTII increased circulating glycerol concentrations at 0.5 and 1.0 h, whereas free fatty acid concentrations were increased at 1.0 and 2.0 h. Western blot analysis showed that MTII specifically increased p-perilipin A and hormone-sensitive lipase only in fat pads that previously had MTII-induced increases in NETO. Phosphorylation increased in IWAT at all time points and IBAT at 0.5 h, but not RWAT or EWAT at any time point. These results show for the first time in rodents that p-perilipin A can serve as an in vivo, fat pad-specific indictor of lipolysis and extend our previous findings showing that central melanocortin stimulation increases WAT lipolysis.

scholarly journals Regulation of adipose tissue lipolysis: phosphorylation of hormone-sensitive lipase in intact rat adipocytes

FEBS Letters ◽  
1980 ◽  
Vol 111 (1) ◽  
pp. 120-124 ◽  
Author(s):  
Per Belfrage ◽  
Gudrun Fredrikson ◽  
Nils Östen Nilsson ◽  
Peter Strålfors
Keyword(s):  
Adipose Tissue ◽  
Hormone Sensitive Lipase ◽  
Rat Adipocytes ◽  
Hormone Sensitive ◽  
Adipose Tissue Lipolysis

scholarly journals Hormone-sensitive lipase of rat adipose tissue. Purification and some properties.

1981 ◽  
Vol 256 (12) ◽  
pp. 6311-6320
Author(s):  
G. Fredrikson ◽  
P. Strålfors ◽  
N.O. Nilsson ◽  
P. Belfrage
Keyword(s):  
Adipose Tissue ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Rat Adipose Tissue
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