scholarly journals Domain-structure analysis of recombinant rat hormone-sensitive lipase

1996 ◽  
Vol 319 (2) ◽  
pp. 411-420 ◽  
Author(s):  
Torben ØSTERLUND ◽  
Birgitta DANIELSSON ◽  
Eva DEGERMAN ◽  
Juan Antonio CONTRERAS ◽  
Gudrun EDGREN ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Domain Structure ◽  
Expression System ◽  
Guanidine Hydrochloride ◽  
Catalytic Triad ◽  
Water Soluble ◽  
Hormone Sensitive Lipase ◽  
Structural Domain ◽  
Hydrolase Fold ◽  
Hormone Sensitive

Hormone-sensitive lipase (HSL) plays a key role in lipid metabolism and overall energy homoeostasis, by controlling the release of fatty acids from stored triglycerides in adipose tissue. Lipases and esterases form a protein superfamily with a common structural fold, called the α/β-hydrolase fold, and a catalytic triad of serine, aspartic or glutamic acid and histidine. Previous alignments between HSL and lipase 2 of Moraxella TA144 have been extended to cover a much larger part of the HSL sequence. From these extended alignments, possible sites for the catalytic triad and α/β-hydrolase fold are suggested. Furthermore, it is proposed that HSL contains a structural domain with catalytic capacity and a regulatory module attached, as well as a structural N-terminal domain unique to this enzyme. In order to test the proposed domain structure, rat HSL was overexpressed and purified to homogeneity using a baculovirus/insect-cell expression system. The purification, resulting in > 99% purity, involved detergent solubilization followed by anion-exchange chromatography and hydrophobic-interaction chromatography. The purified recombinant enzyme was identical to rat adipose-tissue HSL with regard to specific activity, substrate specificity and ability to serve as a substrate for cAMP-dependent protein kinase. The recombinant HSL was subjected to denaturation by guanidine hydrochloride and limited proteolysis. These treatments resulted in more extensive loss of activity against phospholipid-stabilized lipid substrates than against water-soluble substrates, suggesting that the hydrolytic activity can be separated from recognition of lipid substrates. These data support the concept that HSL has at least two major domains.

scholarly journals Species-specific alternative splicing generates a catalytically inactive form of human hormone-sensitive lipase

1997 ◽  
Vol 328 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Henrik LAURELL ◽  
Jacques GROBER ◽  
Cécile VINDIS ◽  
Thierry LACOMBE ◽  
Michèle DAUZATS ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Alternative Splicing ◽  
Cell Lines ◽  
Catalytic Triad ◽  
Hormone Sensitive Lipase ◽  
Human Adipocytes ◽  
Brown Adipose ◽  
Specific Alternative ◽  
Hormone Sensitive ◽  
Species Specific

Hormone-sensitive lipase (HSL) catalyses the rate-limiting step of adipose tissue lipolysis. The enzyme is also expressed in steroidogenic tissues, mammary gland, muscle tissues and macrophages. A novel HSL mRNA termed hHSL-S, 228 bp shorter than the full-length HSL mRNA, was detected in human adipocytes. hHSL-S mRNA results from the in-frame skipping of exon 6, which encodes the serine residue of the catalytic triad. The corresponding 80 kDa protein was identified in human adipocytes after immunoprecipitation. The truncated protein expressed in COS cells showed neither lipase nor esterase activity but was phosphorylated by cAMP-dependent protein kinase. hHSL-S mRNA was found in all human tissues expressing HSL, except brown adipose tissue from newborns. It represented approx. 20% of total HSL transcripts in human subcutaneous adipocytes. No alternative splicing was detected in other mammals. Human and mouse three-exon HSL minigenes transfected into primate and rodent cell lines reproduced the splicing pattern of the endogenous HSL genes. Analysis of hybrid human/mouse minigenes transfected into human cell lines showed that cis-acting elements responsible for the skipping of human exon 6 were restricted to a 247 bp region including exon 6 and the first 19 nt of intron 6. Moreover, divergence in exonic splicing elements between mouse and human was shown to be critical for the species-specific alternative splicing.

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

scholarly journals Effects of Physiological Hypercortisolemia on the Regulation of Lipolysis in Subcutaneous Adipose Tissue1

1998 ◽  
Vol 83 (2) ◽  
pp. 626-631 ◽  
Author(s):  
Jaswinder S. Samra ◽  
Mo L. Clark ◽  
Sandy M. Humphreys ◽  
Ian A. MacDonald ◽  
Peter A. Bannister ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
Sodium Succinate ◽  
Hormone Sensitive Lipase ◽  
Whole Body ◽  
Constant Infusion ◽  
Nonesterified Fatty Acid ◽  
Significant Difference ◽  
Hormone Sensitive ◽  
Subcutaneous Adipose

Cortisol is known to increase whole body lipolysis, yet chronic hypercortisolemia results in increased fat mass. The main aim of the study was to explain these two apparently opposed observations by examining the acute effects of hypercortisolemia on lipolysis in subcutaneous adipose tissue and in the whole body. Six healthy subjects were studied on two occasions. On one occasion hydrocortisone sodium succinate was infused iv to induce hypercortisolemia (mean plasma cortisol concentrations, 1500 ± 100 vs. 335± 25 nmol/L; P < 0.001); on the other occasion (control study) no intervention was made. Lipolysis in the sc adipose tissue of the anterior abdominal wall was studied by measurement of arterio-venous differences, and lipolysis in the whole body was studied by constant infusion of[ 1,2,3-2H5]glycerol for measurement of the systemic glycerol appearance rate. Hypercortisolemia led to significantly increased arterialized plasma nonesterified fatty acid (NEFA; P < 0.01) and blood glycerol concentrations (P < 0.05), with an increase in systemic glycerol appearance (P < 0.05). However, in sc abdominal adipose tissue, hypercortisolemia decreased veno-arterialized differences for NEFA (P < 0.05) and reduced NEFA efflux (P < 0.05). This reduction was attributable to decreased intracellular lipolysis (P < 0.05), reflecting decreased hormone-sensitive lipase action in this adipose depot. Hypercortisolemia caused a reduction in arterialized plasma TAG concentrations (P < 0.05), but without a significant change in the local extraction of TAG (presumed to reflect the action of adipose tissue lipoprotein lipase). There was no significant difference in plasma insulin concentrations between the control and hypercortisolemia study. Site-specific regulation of the enzymes of intracellular lipolysis (hormone-sensitive lipase) and intravascular lipolysis (lipoprotein lipase) may explain the ability of acute cortisol treatment to increase systemic glycerol and NEFA appearance rates while chronically promoting net central fat deposition.

scholarly journals Activation of hormone-sensitive lipase in extracts of adipose tissue

1970 ◽  
Vol 11 (5) ◽  
pp. 466-472
Author(s):  
SU-CHEN TSAI ◽  
PER BELFRAGE ◽  
MARTHA VAUGHAN
Keyword(s):  
Adipose Tissue ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive

Seasonal changes in hormone-sensitive and lipoprotein lipase mRNA concentrations in marmot white adipose tissue

1992 ◽  
Vol 262 (2) ◽  
pp. R177-R181 ◽  
Author(s):  
B. E. Wilson ◽  
S. Deeb ◽  
G. L. Florant
Keyword(s):  
Adipose Tissue ◽  
Lipoprotein Lipase ◽  
White Adipose Tissue ◽  
Mass Gain ◽  
The Body ◽  
Hormone Sensitive Lipase ◽  
Marmota Flaviventris ◽  
Fasting Period ◽  
Hormone Sensitive ◽  
Clear Increase

White adipose tissue (WAT) and plasma samples were obtained from yellow-bellied marmots (Marmota flaviventris) throughout the year. Mean plasma triacylglycerol (TG), free fatty acids (FFAs), and glycerol were determined. There was a clear increase in FFAs and decrease in mean TG and glycerol during the hibernation period when animals were fasting, suggesting increased lipolysis. RNA was isolated from WAT biopsies at four times in the year: spring, summer, fall, and winter. There were significant changes in the relative levels of mRNA for lipoprotein lipase (LPL) and hormone-sensitive lipase (HSL) during the body mass cycle of the marmot. The relative levels of LPL mRNA are high during the mass gain phase of the year and that of HSL mRNA are high during the fasting period when endogenous lipid is utilized. These results suggest that the genes for LPL and HSL are regulated seasonally to control the adipose mass depot in marmots.

Effect of exercise on hormone-sensitive lipase activity in rat adipocytes

1976 ◽  
Vol 230 (2) ◽  
pp. 385-388 ◽  
Author(s):  
JA McGarr ◽  
LB Oscai ◽  
J Borensztajn
Keyword(s):  
Fatty Acids ◽  
Enzyme Activity ◽  
Adipose Tissue ◽  
Free Fatty Acids ◽  
Lipase Activity ◽  
Exercise Program ◽  
Treadmill Running ◽  
Hormone Sensitive Lipase ◽  
Hormone Sensitive ◽  
Fat Pads

Hormone-sensitive lipase activity was measured in adipocytes of rats subjected to a 12-wk program of treadmill running. Enzyme activity in the runners sacrificed immediately after exercise increased 2.5-fold (P less than 0.001) in tissue exposed to epinephrine and threefold (P less than 0.001) in tissue not exposed to epinephrine, when the results were expressed per gram of adipose tissue. Increases of almost the same magnitude were observed in runners sacrificed 24 h after their last bout of work. These significant increases in enzyme activity, however, were the result of a significant reduction in the size of cells in the epididymal fat pads of the exercisers compared with those of the freely eating sedentary animals (68.7 +/- 2.7 mum vs. 82.0 +/- 2.7 mum; P less than 0.01). When the results were expressed on a per-cell basis, therefore, hormone-sensitive lipase activity, assayed in the presence or absence of epinephrine, was unaffected by the exercise program. These results provide evidence that the lipolytic capacity of adipocytes of normal, untrained rats is sufficiently large to meet the increased demand for free fatty acids imposed by the exercise program without the need for an adaptive increase in enzyme activity.

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