title: Lipolysis: pathway under construction.
abstract: OBJECTIVE
  The lipolytic catabolism of stored fat in adipose tissue supplies tissues with fatty acids as metabolites and energy substrates during times of food deprivation. This review focuses on the function of recently discovered enzymes in adipose tissue lipolysis and fatty acid mobilization.
  
  
  RESULTS
  The characterization of hormone-sensitive lipase-deficient mice provided compelling evidence that hormone-sensitive lipase is not uniquely responsible for the hydrolysis of triacylglycerols and diacylglycerols of stored fat. Recently, three different laboratories independently discovered a novel enzyme that also acts in this capacity. We named the enzyme 'adipose triglyceride lipase' in accordance with its predominant expression in adipose tissue, its high substrate specificity for triacylglycerols, and its function in the lipolytic mobilization of fatty acids. Two other research groups showed that adipose triglyceride lipase (named desnutrin and Ca-independent phospholipase A2zeta, respectively) is regulated by the nutritional status and that it might exert acyl-transacylase activity in addition to its activity as triacylglycerol hydrolase. Adipose triglyceride lipase represents a novel type of 'patatin domain-containing' triacylglycerol hydrolase that is more closely related to plant lipases than to other known mammalian metabolic triacylglycerol hydrolases.
  
  
  CONCLUSIONS
  Although the regulation of adipose triglyceride lipase and its physiological function remain to be determined in mouse lines that lack or overexpress the enzyme, present data permit the conclusion that adipose triglyceride lipase is involved in the cellular mobilization of fatty acids, and they require a revision of the concept that hormone-sensitive lipase is the only enzyme involved in the lipolysis of adipose tissue triglycerides.
authors.affiliation: Institute of Molecular Biosciences, Karl-Franzens University Graz, Graz, Austria. rudolf.zechner@uni-graz.at
authors.forename: Rudolf
authors.initials: R
authors.lastname: Zechner
authors.forename: Juliane G
authors.initials: JG
authors.lastname: Strauss
authors.forename: Guenter
authors.initials: G
authors.lastname: Haemmerle
authors.forename: Achim
authors.initials: A
authors.lastname: Lass
authors.forename: Robert
authors.initials: R
authors.lastname: Zimmermann
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000502:physiology; D005227:Fatty Acids / Q000378:metabolism*; D054522:Group VI Phospholipases A2; D006801:Humans; D006868:Hydrolysis; D008049:Lipase / Q000502:physiology; D050356:Lipid Metabolism; D051379:Mice; D010741:Phospholipases A / Q000502:physiology; D000217:Acyltransferases
chemical_list: D002265:Carboxylic Ester Hydrolases; D005227:Fatty Acids; D054522:Group VI Phospholipases A2; D008049:Lipase; D010741:Phospholipases A; C494445:PNPLA2 protein, mouse; D000217:Acyltransferases; C516475:PLA2G6 protein, human; C516476:Pla2g6 protein, mouse