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From Proteopedia
Crystal structure of human HRASLS3.
Structural highlights
Function[PLAT3_HUMAN] Exhibits both phospholipase A1/2 and acyltransferase activities (PubMed:19615464, PubMed:19047760, PubMed:22825852, PubMed:22605381, PubMed:26503625). Shows phospholipase A1 (PLA1) and A2 (PLA2) activity, catalyzing the calcium-independent release of fatty acids from the sn-1 or sn-2 position of glycerophospholipids (PubMed:19615464, PubMed:19047760, PubMed:22825852, PubMed:22605381, PubMed:22923616). For most substrates, PLA1 activity is much higher than PLA2 activity (PubMed:19615464). Shows O-acyltransferase activity,catalyzing the transfer of a fatty acyl group from glycerophospholipid to the hydroxyl group of lysophospholipid (PubMed:19615464). Shows N-acyltransferase activity, catalyzing the calcium-independent transfer of a fatty acyl group at the sn-1 position of phosphatidylcholine (PC) and other glycerophospholipids to the primary amine of phosphatidylethanolamine (PE), forming N-acylphosphatidylethanolamine (NAPE), which serves as precursor for N-acylethanolamines (NAEs) (PubMed:19615464, PubMed:19047760, PubMed:22825852, PubMed:22605381). Exhibits high N-acyltransferase activity and low phospholipase A1/2 activity (PubMed:22825852). Required for complete organelle rupture and degradation that occur during eye lens terminal differentiation, when fiber cells that compose the lens degrade all membrane-bound organelles in order to provide lens with transparency to allow the passage of light. Organelle membrane degradation is probably catalyzed by the phospholipase activity (By similarity).[UniProtKB:Q8R3U1][1] [2] [3] [4] [5] [6] (Microbial infection) Acts as a host factor for picornaviruses: required during early infection to promote viral genome release into the cytoplasm (PubMed:28077878). May act as a cellular sensor of membrane damage at sites of virus entry, which relocalizes to sites of membrane rupture upon virus unfection (PubMed:28077878). Facilitates safe passage of the RNA away from LGALS8, enabling viral genome translation by host ribosome (PubMed:28077878). May also be involved in initiating pore formation, increasing pore size or in maintaining pores for genome delivery (PubMed:28077878). The lipid-modifying enzyme activity is required for this process (PubMed:28077878).[7] Publication Abstract from PubMedLecithin: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. Structural Basis for the Acyltransferase Activity of Lecithin:Retinol Acyltransferase-like Proteins.,Golczak M, Kiser PD, Sears AE, Lodowski DT, Blaner WS, Palczewski K J Biol Chem. 2012 Jul 6;287(28):23790-807. Epub 2012 May 17. PMID:22605381[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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