Human SEIPIN Binds Anionic Phospholipids.

TitleHuman SEIPIN Binds Anionic Phospholipids.
Publication TypeJournal Article
Year of Publication2018
AuthorsYan, R, Qian, H, Lukmantara, I, Gao, M, Du, X, Yan, N, Yang, H
JournalDev Cell
Volume47
Issue2
Pagination248-256.e4
Date Published2018 10 22
ISSN1878-1551
KeywordsAdipocytes, Adipogenesis, Adipose Tissue, Cryoelectron Microscopy, Endoplasmic Reticulum, GTP-Binding Protein gamma Subunits, HEK293 Cells, HeLa Cells, Humans, Lipid Droplets, Lipid Metabolism, Membrane Proteins, Phospholipids
Abstract

The biogenesis of lipid droplets (LDs) and the development of adipocytes are two key aspects of mammalian fat storage. SEIPIN, an integral membrane protein of the endoplasmic reticulum (ER), plays a critical role in both LD formation and adipogenesis. The molecular function of SEIPIN, however, has yet to be elucidated. Here, we report the cryogenic electron microscopy structure of human SEIPIN at 3.8 Å resolution. SEIPIN exists as an undecamer, and this oligomerization state is critical for its physiological function. The evolutionarily conserved lumenal domain of SEIPIN forms an eight-stranded β sandwich fold. Both full-length SEIPIN and its lumenal domain can bind anionic phospholipids including phosphatidic acid. Our results suggest that SEIPIN forms a scaffold that helps maintain phospholipid homeostasis and surface tension of the ER.

DOI10.1016/j.devcel.2018.09.010
Alternate JournalDev. Cell
PubMed ID30293840