title: Molecular Basis of ABHD5 Lipolysis Activation.
abstract: Alpha-beta hydrolase domain-containing 5 (ABHD5), the defective gene in human Chanarin-Dorfman syndrome, is a highly conserved regulator of adipose triglyceride lipase (ATGL)-mediated lipolysis that plays important roles in metabolism, tumor progression, viral replication, and skin barrier formation. The structural determinants of ABHD5 lipolysis activation, however, are unknown. We performed comparative evolutionary analysis and structural modeling of ABHD5 and ABHD4, a functionally distinct paralog that diverged from ABHD5 ~500 million years ago, to identify determinants of ABHD5 lipolysis activation. Two highly conserved ABHD5 amino acids (R299 and G328) enabled ABHD4 (ABHD4 N303R/S332G) to activate ATGL in Cos7 cells, brown adipocytes, and artificial lipid droplets. The corresponding ABHD5 mutations (ABHD5 R299N and ABHD5 G328S) selectively disrupted lipolysis without affecting ATGL lipid droplet translocation or ABHD5 interactions with perilipin proteins and ABHD5 ligands, demonstrating that ABHD5 lipase activation could be dissociated from its other functions. Structural modeling placed ABHD5 R299/G328 and R303/G332 from gain-of-function ABHD4 in close proximity on the ABHD protein surface, indicating they form part of a novel functional surface required for lipase activation. These data demonstrate distinct ABHD5 functional properties and provide new insights into the functional evolution of ABHD family members and the structural basis of lipase regulation.
authors.affiliation: Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA.|Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Sanders
authors.affiliation: Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA.|Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Huamei
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA.|Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Mladenovic
authors.affiliation: Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: Yan Yuan
authors.initials: YY
authors.lastname: Tseng
authors.affiliation: Center for Integrative Metabolic and Endocrine Research Wayne State University School of Medicine, Detroit, MI 48201, USA.|Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA.
authors.forename: James G
authors.initials: JG
authors.lastname: Granneman
mesh_terms: D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D052437:Adipocytes, Brown / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D008049:Lipase / Q000378:metabolism; D066292:Lipid Droplets; D008066:Lipolysis / Q000235:genetics*; D008245:Lysophospholipase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D054730:Protein Interaction Domains and Motifs; D021381:Protein Transport; D013329:Structure-Activity Relationship; D000217:Acyltransferases
chemical_list: D051103:1-Acylglycerol-3-Phosphate O-Acyltransferase; D008049:Lipase; D008245:Lysophospholipase; C492986:Abhd5 protein, mouse; C494445:PNPLA2 protein, mouse; D000217:Acyltransferases