7RSL

Seipin forms a flexible cage at lipid droplet formation sites

Summary for 7RSL

• Entry DOI: 10.2210/pdb7rsl/pdb
• EMDB information: 24674
• Descriptor: Seipin (1 entity in total)
• Functional Keywords: lipid droplets, lipid droplet formation, complex, endoplasmic reticulum, fat storage, membrane protein
• Biological source: Saccharomyces cerevisiae (baker's yeast)
• Total number of polymer chains: 10
• Total formula weight: 326239.53

Authors

Arlt, H.,Sui, X.,Folger, B.,Adams, C.,Chen, X.,Remme, R.,Hamprecht, F.A.,DiMaio, F.,Liao, M.,Goodman, J.M.,Farese Jr, R.V.,Walther, T.C. (deposition date: 2021-08-11, release date: 2022-02-09, Last modification date: 2024-06-05)

Primary citation

Arlt, H.,Sui, X.,Folger, B.,Adams, C.,Chen, X.,Remme, R.,Hamprecht, F.A.,DiMaio, F.,Liao, M.,Goodman, J.M.,Farese Jr., R.V.,Walther, T.C.
Seipin forms a flexible cage at lipid droplet formation sites.
Nat.Struct.Mol.Biol., 29:194-202, 2022

PubMed Abstract: Lipid droplets (LDs) form in the endoplasmic reticulum by phase separation of neutral lipids. This process is facilitated by the seipin protein complex, which consists of a ring of seipin monomers, with a yet unclear function. Here, we report a structure of S. cerevisiae seipin based on cryogenic-electron microscopy and structural modeling data. Seipin forms a decameric, cage-like structure with the lumenal domains forming a stable ring at the cage floor and transmembrane segments forming the cage sides and top. The transmembrane segments interact with adjacent monomers in two distinct, alternating conformations. These conformations result from changes in switch regions, located between the lumenal domains and the transmembrane segments, that are required for seipin function. Our data indicate a model for LD formation in which a closed seipin cage enables triacylglycerol phase separation and subsequently switches to an open conformation to allow LD growth and budding.

PubMed: 35210614
DOI: 10.1038/s41594-021-00718-y

Experimental method

ELECTRON MICROSCOPY (3.45 Å)