title: AIG1 and ADTRP are atypical integral membrane hydrolases that degrade bioactive FAHFAs.
abstract: Enzyme classes may contain outlier members that share mechanistic, but not sequence or structural, relatedness with more common representatives. The functional annotation of such exceptional proteins can be challenging. Here, we use activity-based profiling to discover that the poorly characterized multipass transmembrane proteins AIG1 and ADTRP are atypical hydrolytic enzymes that depend on conserved threonine and histidine residues for catalysis. Both AIG1 and ADTRP hydrolyze bioactive fatty acid esters of hydroxy fatty acids (FAHFAs) but not other major classes of lipids. We identify multiple cell-active, covalent inhibitors of AIG1 and show that these agents block FAHFA hydrolysis in mammalian cells. These results indicate that AIG1 and ADTRP are founding members of an evolutionarily conserved class of transmembrane threonine hydrolases involved in bioactive lipid metabolism. More generally, our findings demonstrate how chemical proteomics can excavate potential cases of convergent or parallel protein evolution that defy conventional sequence- and structure-based predictions.
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: William H
authors.initials: WH
authors.lastname: Parsons
authors.affiliation: Salk Institute for Biological Studies, Clayton Foundation Laboratories for Peptide Biology, Helmsley Center for Genomic Medicine, La Jolla, California 92037, United States.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Kolar
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: Siddhesh S
authors.initials: SS
authors.lastname: Kamat
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: Armand B
authors.initials: AB
authors.lastname: Cognetta
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: Jonathan J
authors.initials: JJ
authors.lastname: Hulce
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: Enrique
authors.initials: E
authors.lastname: Saez
authors.affiliation: Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, Massachusetts 02215, United States.
authors.forename: Barbara B
authors.initials: BB
authors.lastname: Kahn
authors.affiliation: Salk Institute for Biological Studies, Clayton Foundation Laboratories for Peptide Biology, Helmsley Center for Genomic Medicine, La Jolla, California 92037, United States.
authors.forename: Alan
authors.initials: A
authors.lastname: Saghatelian
authors.affiliation: The Skaggs Institute for Chemical Biology, Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037.
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Cravatt
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004952:Esters; D005227:Fatty Acids / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D006867:Hydrolases / Q000235:genetics / Q000378:metabolism*; D006880:Hydroxy Acids / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed
chemical_list: C568706:ADTRP protein, human; C430102:AIG1 protein, human; D004952:Esters; D005227:Fatty Acids; D006880:Hydroxy Acids; D008565:Membrane Proteins; D006867:Hydrolases