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Adipose triglyceride lipase

From Wikipedia, the free encyclopedia

PNPLA2
Identifiers
AliasesPNPLA2, 1110001C14Rik, ATGL, PEDF-R, TTS-2.2, TTS2, iPLA2zeta, FP17548, patatin like phospholipase domain containing 2
External IDsOMIM: 609059; MGI: 1914103; HomoloGene: 10687; GeneCards: PNPLA2; OMA:PNPLA2 - orthologs
Orthologs
SpeciesHumanMouse
Entrez

57104

66853

Ensembl

ENSG00000177666

ENSMUSG00000025509

UniProt

Q96AD5

Q8BJ56

RefSeq (mRNA)

NM_020376

NM_001163689
NM_025802

RefSeq (protein)

NP_065109

NP_001157161
NP_080078

Location (UCSC)Chr 11: 0.82 – 0.83 MbChr 7: 141.04 – 141.04 Mb
PubMed search[3][4]
Wikidata
View/Edit HumanView/Edit Mouse

Adipose triglyceride lipase, also known as patatin-like phospholipase domain-containing protein 2 and ATGL, is an enzyme that in humans is encoded by the PNPLA2 gene.[5][6][7] ATGL catalyses the first reaction of lipolysis,[8] where triacylglycerols are hydrolysed to diacylglycerols.[9]

Properties

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ATGL has very high substrate specificity for triacylglycerols.[10] It contains a catalytic dyad using serine-aspartic acid.[9]

Function

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ATGL catalyses the first reaction of lipolysis.[8] It hydrolysis triacylglycerols to diacylglycerols[9] by attacking the fatty acid attached to carbon-3 of glycerol.

ATGL acts as a control mechanism of lipolysis, as variations in diacylglycerol concentration impact enzymes in later stages of lipolysis.[11]

Clinical significance

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Defects in ATGL can cause problems in lipolysis, leading to neutral lipid storage disease.[12] As triacylglycerols are not hydrolysed to diacylglycerols, there is a build-up of triacylglycerol droplets in granulocytes.[12]

ATGL is regulated by insulin, and is similar to structure with adiponutrin, a protein that is regulated by nutrition. When there is a lack of insulin, there is an increased expression of the ATGL protein. Because adipose tissue triglyceride is a major form of energy storage, the study of how ATGL regulation and dysregulation can lead to potential problems will increase understanding of the pathophysiology behind metabolic disorders.[13] ATGL is also the key enzyme that would be able to maintain a balance between mobilization and lipid storage. Lipolytic breakdown performed by ATGL would impact regulatory functions including but not limited to cell death, growth, signaling, metabolism, and gene expression.[14][15]

Regulation

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There must be mechanisms set to maintain the balance between energy storage, and energy release; a dysregulation in the equilibrium result in metabolic disorder, a prime one being diabetes.[13] Adipose Triglyceride Lipase (ATGL) can undergo activation through two different pathways: transcriptionally and through post-translational modification. Through the transcriptional pathway, Beta-adrenergic, a receptor that can form a complex with agonist such as epinephrine, results in the signal transduction pathway activation of Adipose Triglyceride Lipase (ATGL). The alternative pathway is through a post-translational modification specifically phosphorylation of a serine 406 residue located on the enzyme by a kinase known as AMP activated protein kinase (AMPK). Both pathways facilitate the activation of the enzyme, resulting in the breakdown of triglyceride.[16]

Insulin is a hormone that regulate the enzyme ATGL, it inhibits the enzyme by favoring lipid storage over lipolysis.[13] One pathway of inhibition of ATGL when insulin is present is the activation of SIRT1, which inhibits FoxO1.[16][17] Specifically, FoxO1 is repressed from localizing in the nucleus by deacetylation in adipocytes.[16][18]

References

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  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000177666 – Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000025509 – Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ Andersson B, Wentland MA, Ricafrente JY, Liu W, Gibbs RA (April 1996). "A "double adaptor" method for improved shotgun library construction". Analytical Biochemistry. 236 (1): 107–113. doi:10.1006/abio.1996.0138. PMID 8619474.
  6. ^ Wilson PA, Gardner SD, Lambie NM, Commans SA, Crowther DJ (September 2006). "Characterization of the human patatin-like phospholipase family". Journal of Lipid Research. 47 (9): 1940–1949. doi:10.1194/jlr.M600185-JLR200. PMID 16799181.
  7. ^ Kienesberger PC, Oberer M, Lass A, Zechner R (April 2009). "Mammalian patatin domain containing proteins: a family with diverse lipolytic activities involved in multiple biological functions". Journal of Lipid Research. 50 (Suppl): S63–S68. doi:10.1194/jlr.R800082-JLR200. PMC 2674697. PMID 19029121.
  8. ^ a b Ojha S, Budge H, Symonds ME (2014). "Adipocytes in Normal Tissue Biology". In McManus LM, Mitchell RN (eds.). Pathobiology of Human Disease. San Diego: Academic Press. pp. 2003–2013. doi:10.1016/b978-0-12-386456-7.04408-7. ISBN 978-0-12-386457-4.
  9. ^ a b c Lehner R, Quiroga AD (2016). "Chapter 5 - Fatty Acid Handling in Mammalian Cells". In Ridgway ND, McLeod RS (eds.). Biochemistry of Lipids, Lipoproteins and Membranes (Sixth ed.). Boston: Elsevier. pp. 149–184. doi:10.1016/b978-0-444-63438-2.00005-5. ISBN 978-0-444-63438-2.
  10. ^ Tsiloulis T, Watt MJ (2015). "Chapter Eight - Exercise and the Regulation of Adipose Tissue Metabolism". In Bouchard C (ed.). Progress in Molecular Biology and Translational Science. Molecular and Cellular Regulation of Adaptation to Exercise. Vol. 135. Academic Press. pp. 175–201. doi:10.1016/bs.pmbts.2015.06.016. ISBN 9780128039915. PMID 26477915.
  11. ^ Zhang X, Heckmann BL, Liu J (2013-01-01). "Studying lipolysis in adipocytes by combining siRNA knockdown and adenovirus-mediated overexpression approaches". In Yang P, Li H (eds.). Lipid Droplets. Methods in Cell Biology. Vol. 116. Academic Press. pp. 83–105. doi:10.1016/b978-0-12-408051-5.00006-1. ISBN 9780124080515. PMC 4529287. PMID 24099289.
  12. ^ a b Bongarzone ER, Givogri MI, Darryl C, DiMauro S (January 2012). "Inborn Metabolic Defects of Lysosomes, Peroxisomes, Carbohydrates, Fatty Acids and Mitochondria.". In Brady ST, Siegel GJ, Albers RW, Price DL (eds.). Basic Neurochemistry (Eighth ed.). New York: Academic Press. pp. 755–782. doi:10.1016/b978-0-12-374947-5.00043-2. ISBN 978-0-12-374947-5.
  13. ^ a b c Kershaw EE, Hamm JK, Verhagen LA, Peroni O, Katic M, Flier JS (January 2006). "Adipose triglyceride lipase: function, regulation by insulin, and comparison with adiponutrin". Diabetes. 55 (1): 148–157. doi:10.2337/diabetes.55.01.06.db05-0982. PMC 2819178. PMID 16380488.
  14. ^ Cerk IK, Wechselberger L, Oberer M (2017-12-18). "Adipose Triglyceride Lipase Regulation: An Overview". Current Protein & Peptide Science. 19 (2): 221–233. doi:10.2174/1389203718666170918160110. PMC 7613786. PMID 28925902.
  15. ^ Liu S, Promes JA, Harata M, Mishra A, Stephens SB, Taylor EB, et al. (June 2020). "Adipose Triglyceride Lipase Is a Key Lipase for the Mobilization of Lipid Droplets in Human β-Cells and Critical for the Maintenance of Syntaxin 1a Levels in β-Cells". Diabetes. 69 (6): 1178–1192. doi:10.2337/db19-0951. PMC 7243295. PMID 32312867.
  16. ^ a b c Li T, Guo W, Zhou Z (December 2021). "Adipose Triglyceride Lipase in Hepatic Physiology and Pathophysiology". Biomolecules. 12 (1): 57. doi:10.3390/biom12010057. PMC 8773762. PMID 35053204.
  17. ^ Chakrabarti P, English T, Karki S, Qiang L, Tao R, Kim J, et al. (September 2011). "SIRT1 controls lipolysis in adipocytes via FOXO1-mediated expression of ATGL". Journal of Lipid Research. 52 (9): 1693–1701. doi:10.1194/jlr.M014647. PMC 3151689. PMID 21743036.
  18. ^ Chakrabarti P, Kandror KV (May 2009). "FoxO1 controls insulin-dependent adipose triglyceride lipase (ATGL) expression and lipolysis in adipocytes". The Journal of Biological Chemistry. 284 (20): 13296–13300. doi:10.1074/jbc.C800241200. PMC 2679428. PMID 19297333.

Further reading

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