title: Structural basis for the acyltransferase activity of lecithin:retinol acyltransferase-like proteins.
abstract: Lecithin:retinol acyltransferase-like proteins, also referred to as HRAS-like tumor suppressors, comprise a vertebrate subfamily of papain-like or NlpC/P60 thiol proteases that function as phospholipid-metabolizing enzymes. HRAS-like tumor suppressor 3, a representative member of this group, plays a key role in regulating triglyceride accumulation and energy expenditure in adipocytes and therefore constitutes a novel pharmacological target for treatment of metabolic disorders causing obesity. Here, we delineate a catalytic mechanism common to lecithin:retinol acyltransferase-like proteins and provide evidence for their alternative robust lipid-dependent acyltransferase enzymatic activity. We also determined high resolution crystal structures of HRAS-like tumor suppressor 2 and 3 to gain insight into their active site architecture. Based on this structural analysis, two conformational states of the catalytic Cys-113 were identified that differ in reactivity and thus could define the catalytic properties of these two proteins. Finally, these structures provide a model for the topology of these enzymes and allow identification of the protein-lipid bilayer interface. This study contributes to the enzymatic and structural understanding of HRAS-like tumor suppressor enzymes.
authors.affiliation: Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106, USA. mxg149@case.edu
authors.forename: Marcin
authors.initials: M
authors.lastname: Golczak
authors.forename: Philip D
authors.initials: PD
authors.lastname: Kiser
authors.forename: Avery E
authors.initials: AE
authors.lastname: Sears
authors.forename: David T
authors.initials: DT
authors.lastname: Lodowski
authors.forename: William S
authors.initials: WS
authors.lastname: Blaner
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Palczewski
mesh_terms: D000215:Acylation; D000217:Acyltransferases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D055162:Biocatalysis; D020134:Catalytic Domain; D002851:Chromatography, High Pressure Liquid; D018360:Crystallography, X-Ray; D003545:Cysteine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D006801:Humans; D013058:Mass Spectrometry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D054467:Phospholipases A2; D054512:Phospholipases A2, Calcium-Independent / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D025521:Tumor Suppressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
chemical_list: D010743:Phospholipids; D025521:Tumor Suppressor Proteins; D000217:Acyltransferases; C056942:lecithin-retinol acyltransferase; C530743:PLAAT2 protein, human; C490065:PLAAT3 protein, human; D054467:Phospholipases A2; D054512:Phospholipases A2, Calcium-Independent; D003545:Cysteine