6mlu | pdb_00006mlu
Cryo-EM structure of lipid droplet formation protein Seipin/BSCL2
Structural highlights
Function[BSCL2_DROME] Is a regulator of lipid catabolism essential for adipocyte differentiation. May also be involved in the central regulation of energy homeostasis (By similarity). Necessary for correct lipid storage and lipid droplets maintenance; plays a tissue-autonomous role in controlling lipid storage in adipocytes and in preventing ectopic lipid droplet formation in non-adipose tissues. May participate in phosphatidic acid metabolism and subsequently down-regulate lipogenesis.[UniProtKB:Q9Z2E9][1] Publication Abstract from PubMedMetabolic energy is stored in cells primarily as triacylglycerols in lipid droplets (LDs), and LD dysregulation leads to metabolic diseases. The formation of monolayer-bound LDs from the endoplasmic reticulum (ER) bilayer is poorly understood, but the ER protein seipin is essential to this process. In this study, we report a cryo-electron microscopy structure and functional characterization of Drosophila melanogaster seipin. The structure reveals a ring-shaped dodecamer with the luminal domain of each monomer resolved at approximately 4.0 A. Each luminal domain monomer exhibits two distinctive features: a hydrophobic helix (HH) positioned toward the ER bilayer and a beta-sandwich domain with structural similarity to lipid-binding proteins. This structure and our functional testing in cells suggest a model in which seipin oligomers initially detect forming LDs in the ER via HHs and subsequently act as membrane anchors to enable lipid transfer and LD growth. Cryo-electron microscopy structure of the lipid droplet-formation protein seipin.,Sui X, Arlt H, Brock KP, Lai ZW, DiMaio F, Marks DS, Liao M, Farese RV Jr, Walther TC J Cell Biol. 2018 Oct 16. pii: jcb.201809067. doi: 10.1083/jcb.201809067. PMID:30327422[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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