title: Identification of diverse lipid droplet targeting motifs in the PNPLA family of triglyceride lipases.
abstract: Members of the Patatin-like Phospholipase Domain containing Protein A (PNPLA) family play key roles in triglyceride hydrolysis, energy metabolism, and lipid droplet (LD) homoeostasis. Here we report the identification of two distinct LD targeting motifs (LTM) for PNPLA family members. Transient transfection of truncated versions of human adipose triglyceride lipase (ATGL, also known as PNPLA2), PNPLA3/adiponutrin, or PNPLA5 (GS2-like) fused to GFP revealed that the C-terminal third of these proteins contains sequences that are sufficient for targeting to LDs. Furthermore, fusing the C-termini of PNPLA3 or PNPLA5 confers LD localization to PNPLA4, which is otherwise cytoplasmic. Analyses of additional mutants in ATGL, PNPLA5, and Brummer Lipase, the Drosophila homolog of mammalian ATGL, identified two different types of LTMs. The first type, in PNPLA5 and Brummer lipase, is a set of loosely conserved basic residues, while the second type, in ATGL, is contained within a stretch of hydrophobic residues. These results show that even closely related members of the PNPLA family employ different molecular motifs to associate with LDs.
authors.affiliation: Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York, United States of America.
authors.forename: Sricharan
authors.initials: S
authors.lastname: Murugesan
authors.forename: Elysa B
authors.initials: EB
authors.lastname: Goldberg
authors.forename: Eda
authors.initials: E
authors.lastname: Dou
authors.forename: William J
authors.initials: WJ
authors.lastname: Brown
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008049:Lipase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D050356:Lipid Metabolism; D008055:Lipids / Q000737:chemistry*; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D016415:Sequence Alignment; D000217:Acyltransferases
chemical_list: D008049:Lipase; D008055:Lipids; C549685:PNPLA5 protein, human; D000217:Acyltransferases