Human SEIPIN Binds Anionic Phospholipids

Yan, Renhong; Qian, Hui‐Fen; Lukmantara, Ivan; Gao, Mingming; Du, Ximing; Yan, Nieng; Yang, Hongyuan

doi:10.1016/j.devcel.2018.09.010

Cited by 184 publications

(276 citation statements)

References 43 publications

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“…C) Alignment of Cdc50p and a monomer of human seipin (PDB 6DS5 44 ), a lipid binding protein illustrates the similar folds, although loops of Cdc50p are more extensive. The sequence identity between the two proteins is only 4%.…”

Section: Supplementary Data Figurementioning

confidence: 99%

Structure and autoregulation of a P4-ATPase lipid flippase

Timcenko

Lyons

Januliene

et al. 2019

Preprint

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SummaryP4-ATPases are lipid flippases that drive active transport of phospholipids from the exoplasmic or lumenal to the cytosolic leaflets of eukaryotic membranes to maintain their asymmetric lipid composition. The molecular architecture of P4-ATPases and how they work in lipid recognition and transport has remained elusive. Using cryo-electron microscopy we have determined the structures of a P4-ATPase, specifically of theSaccharomyces cerevisiaeDrs2p-Cdc50p, which is a phosphatidylserine and phosphatidylethanolamine specific lipid flippase. Drs2p-Cdc50p is autoinhibited by the Drs2p C-terminal tail and activated by phosphatidylinositol-4 phosphate (PI4P). We present three structures representing an autoinhibited, an intermediate, and a fully activated state. The analysis highlights specific features of P4-ATPases and reveals sites of auto-inhibition and PI4P-dependent activation. We observe the opening of a putative flippase pathway engaging conserved residues Ile508 of transmembrane segment 4 and Lys1018 and polar residues of transmembrane segment 5 in the centre of the lipid bilayer.

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Section: Supplementary Data Figurementioning

confidence: 99%

Structure and autoregulation of a P4-ATPase lipid flippase

Timcenko

Lyons

Januliene

et al. 2019

Preprint

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“…Importantly, the neutral and polar lipid constituents of adiposomes can be controlled as required for a particular experiment. For example, the role of protein-phospholipid binding in membrane targeting can be explored through manipulation of the adiposome phospholipid composition (Lemmon, 2008;Yan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

“…The role of phosphatidic acid in LD protein targeting has been reported (Barneda et al, 2015;Yan et al, 2018), but the role of phosphatidyl inositol (PI), which is abundant on the LD, has attracted little attention (Bartz et al, 2007a;Tauchi-Sato et al, 2002). However, PI is known to be involved in protein binding in other contexts (Phan et al, 2016), so further investigation is well warranted.…”

Section: Introductionmentioning

confidence: 99%

Adiposome Targeting and Enzymatic Activity of Lipid Droplet-Specific Proteins

Zhang

et al. 2020

Preprint

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RUNNING TITLESProtein targeting to adiposomes and enzymatic activity. ABBREVIATIONS DOPC: 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphocholine. DOPE: 1,2-di-(9Z-octadecenoyl)-sn-glycero-3phosphoethanolamine. PI: phosphatidylinositol. Liver PI: L-α-phosphatidylinositol (Liver, Bovine) (sodium salt). TAG: triacylglycerol. ADRP: adipose differentiation-related protein. TIP47: tail-interacting protein of 47 kDa. PLINs: perilipin family proteins. ATGL: adipose triglyceride lipase. ALD: artificial lipid droplet. LD: lipid droplet. FFF-MALS: 2 field flow fractionation-multi-angle light scattering. TEM: Transmission electron microscope. SUMMARYNew strategies to decode the specific protein targeting mechanism on lipid droplet (LD) are urgently needed.Using adiposome, the LD binding of perilipin 2 (PLIN2), perilipin 3 (PLIN3), and adipose triglyceride lipase (ATGL) were studied. Scatchard analysis found that the binding of PLIN2 to the adiposome surface was saturable, pointing to a specific membrane binding partner. Phosphatidylinositol (PI) was found to inhibit PLIN2 binding while it did not impede PLIN3. Structural analysis combined with mutagenesis revealed that the 73 rd glutamic acid of PLIN2 is significant for the effect of PI on the protein binding. The presence of PI significantly stimulated the activity of ATGL in vitro. The phosphorylation site mutants of ATGL were found reducing the lipase activity in the adiposome system. Our study demonstrates the utility of adiposome as a powerful, manipulatable model system for the characterization of LD binding and enzymatic activity of LD proteins in vitro.

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“…Of note, seipin has been recently shown to mark the sites of LD formation 25 , and stand-alone deletion of seipin has been shown to lead to NL accumulation in the ER and delayed LD formation 26 . To test this hypothesis we first prepared a model of the transmembrane region of seipin based on the recently determined cryo-EM structures of the soluble part of seipin 27,28 and we embedded this model in a large membrane patch with 2% TG (Figure 4A,B). We next measured the concentration of TG molecules as a function of the distance from the protein complex, and we found that interactions between the TG molecules and the seipin complex raise the local concentration of TG in the proximity of the protein to 4%, twice the initial value in the bulk membrane ( Figure 4C,D) in our MD simulations.…”

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confidence: 99%

“…An elastic network, defined using MARTINI2 standard parameters for force constant and cutoffs, was used to keep the secondary structure of the helices. The position of the transmembrane helices was obtained from the coordinates of the terminal residues of the cryoEM structure of human Seipin, present in the PDB data bank with the code 6D5S27 . After a short 10 ps equilibration without restraints and subsequent 4 ns equilibration with positional restraint along all the directions (Fc=1000 kj/mol nm 2 ), positional restraints of Fc=1000 kj/mol nm 2 along…”

mentioning

confidence: 99%

Lipid droplet biogenesis is driven by liquid-liquid phase separation

Zoni

Khaddaj

Campomanes

et al. 2019

Preprint

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Cells store energy in the form of neutral lipids packaged into micrometer-sized organelles named lipid droplets (LD). These structures emerge from the endoplasmic reticulum (ER), but their biogenesis remains poorly understood. Using molecular simulations, we found that fat accumulation and LD formation are described by a liquid-liquid phase separation (LLPS) process. Within this framework, we could identify how ER membrane properties modulate LD formation, and we could directly test our computational predictions by combining yeast genetics with fluorescence microscopy. Our data suggest that the specific lipid composition of the ER together with its peculiar physical properties, such as low membrane tension and membrane curvature, promote the packaging of neutral lipids into LD, preventing their accumulation in the ER membrane. Our results provide a new conceptual understanding of LD biogenesis in the context of ER homeostasis and function.

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Human SEIPIN Binds Anionic Phospholipids

Abstract: Highlights d Human SEIPIN exists as an undecamer d The oligomerization state of SEIPIN is critical for its physiological function d The lumenal domain of SEIPIN forms an eight-stranded b sandwich fold d Both full-length SEIPIN and its lumenal domain bind anionic phospholipids

Cited by 184 publications

References 43 publications

Structure and autoregulation of a P4-ATPase lipid flippase

Structure and autoregulation of a P4-ATPase lipid flippase

Adiposome Targeting and Enzymatic Activity of Lipid Droplet-Specific Proteins

Lipid droplet biogenesis is driven by liquid-liquid phase separation

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