patatin-like phospholipase domain-containing protein 2 (adipose triglyceride lipase, desnutrin, transport-secretion protein 2, TTS2, TTS2.2, Ca+2-independent phospholipase A2, IPLA2-zeta, pigment epithelium-derived factor, PNPLA2, ATGL, FP17548)

Function: - triglyceride lipolysis - catalyzes initial step in triglyceride hydrolysis in adipocyte & non-adipocyte lipid droplets - has acylglycerol transacylase activity - may act coordinately with LIPE/HLS within the lipolytic cascade - regulates adiposome size & may be involved in degradation of adiposomes - role in energy homeostasis (putative) - role in the response of organism to starvation, enhancing hydrolysis of triglycerides & providing free fatty acids to other tissues to be oxidized in situations of energy depletion - activated by ABHD5 & SERPINF1 - ATP not essential - interacts with ABHD5, association stimulates PNPLA2 triglyceride hydrolase activity (putative) - interacts with SERPINF1 - despite a colocalization in lipid droplets, probably does not interact with PLIN (putative) - may be phosphorylated (putative) Triacylglycerol + H₂O diacylglycerol + a carboxylate Inhibition: - inhibited by BEL ((E)-6-(bromomethylene)-3-(1-naphthalenyl)- 2H-tetrahydropyran-2-one), a suicide substrate inhibitor Kinetic parameters: - Optimum pH is 7.5 (1,2-dilinoleoyl)-phosphatidylcholine as substrate Structure: contains 1 patatin domain Compartment: lipid droplet membrane, cell membrane Alternative splicing: named isoforms=2 Expression: - highest expression in adipose tissue - detected in heart, skeletal muscle, & portions of the gastrointestinal tract - detected in normal retina & retinoblastoma cells - detected in retinal pigment epithelium > inner segments of photoreceptors & ganglion cell layer of the neural retina (at protein level) - induced during differentiation of primary preadipocytes to adipocytes - expression increased from fetal to adult in retinal pigment epithelium Polymorphism: - genetic variations in PNPLA2 may be associated with plasma free fatty acids, serum triglycerides levels, & fasting serum glucose concentrations Pathology: - genetic variations in PNPLA2 may be associated with risk of diabetes mellitus type 2 - defects in PNPLA2 are the cause of neutral lipid storage disease with myopathy

General

glycoprotein membrane protein patatin-like phospholipase domain-containing protein (PNPLA)

Properties

SIZE: MW = 55 kD entity length = 504 aa COMPARTMENT: cellular membrane MOTIF: transmembrane domain {9-29} Patatin {10-179} MOTIF: N-glycosylation site {N39} GXSXG {45-49} serine residue {S47}

Database Correlations

UniProt Q96AD5 Pfam PF01734 ENZYME 3.1.1.3

References

UniProt :accession Q96AD5