Laboratory :
Author :
Revue :
Year :

Retinyl esters form lipid droplets independently of triacylglycerol and seipin
Martijn R Molenaar # 1, Kamlesh K Yadav # 2, Alexandre Toulmay , Tsjerk A Wassenaar , Muriel C Mari , Lucie Caillon , Aymeric Chorlay , Ivan E Lukmantara , Maya W Haaker , Richard W Wubbolts , Martin Houweling , Arie Bas Vaandrager , Xavier Pri
J Cell Biol - 220(10) - doi: 10.1083/jcb.202011071 - 2021
Lipid droplets store neutral lipids, primarily triacylglycerol and steryl esters. Seipin plays a role in lipid droplet biogenesis and is thought to determine the site of lipid droplet biogenesis and the size of newly formed lipid droplets. Here we show a seipin-independent pathway of lipid droplet biogenesis. In silico and in vitro experiments reveal that retinyl esters have the intrinsic propensity to sequester and nucleate in lipid bilayers. Production of retinyl esters in mammalian and yeast cells that do not normally produce retinyl esters causes the formation of lipid droplets, even in a yeast strain that produces only retinyl esters and no other neutral lipids. Seipin does not determine the size or biogenesis site of lipid droplets composed of only retinyl esters or steryl esters. These findings indicate that the role of seipin in lipid droplet biogenesis depends on the type of neutral lipid stored in forming droplets.
Fat inclusions strongly alter membrane mechanics
Alexandre Santinho, Aymeric,Chorlay, LionelForet, Abdou RachidThiam
Biophysical Journal - 4 607-617 - - 2021
Neutral lipids (NLs) are apolar oil molecules synthesized in the endoplasmic reticulum bilayer upon diverse biological stimuli. NLs synthesized are released in the hydrophobic core of the bilayer. At a critical concentration, NLs condense by phase separation and nucleate a lipid droplet (LD). After an LD forms, a fraction of NLs can be present in the bilayer but at a concentration below that of the nucleation. Here, we study whether and how the accumulation of NLs alters a lipid bilayer’s mechanical properties. In synthetic systems, we found that NLs proffer unusual bilayer stretching capacities, especially in the presence of negatively curved phospholipids. This impact becomes spectacular when an LD is contiguous with the bilayer and supplies it with NLs. The tested NLs markedly decrease the bilayer area expansion modulus and significantly increase lysis tension but had opposite effects on membrane bending rigidity. Our data unveil how NL molecules modify overall membrane mechanics, the alteration of which may be linked to pathologies or anticancer treatments targeting NLs.

Pre-existing bilayer stresses modulate triglyceride accumulation in the ER versus lipid droplets
Valeria Zoni Rasha Khaddaj Pablo Campomanes Abdou Rachid Thiam Roger Schneiter Stefano Vanni
e-Life - 10 62886 - 10.7554/eLife.62886 - 2021
Cells store energy in the form of neutral lipids (NLs) packaged into micrometer-sized organelles named lipid droplets (LDs). These structures emerge from the endoplasmic reticulum (ER) at sites marked by the protein seipin, but the mechanisms regulating their biogenesis remain poorly understood. Using a combination of molecular simulations, yeast genetics, and fluorescence microscopy, we show that interactions between lipids' acyl-chains modulate the propensity of NLs to be stored in LDs, in turn preventing or promoting their accumulation in the ER membrane. Our data suggest that diacylglycerol, which is enriched at sites of LD formation, promotes the packaging of NLs into LDs, together with ER-abundant lipids, such as phosphatidylethanolamine. On the opposite end, short and saturated acyl-chains antagonize fat storage in LDs and promote accumulation of NLs in the ER. Our results provide a new conceptual understanding of LD biogenesis in the context of ER homeostasis and function.


- For any publication having received the support of the IPGG (presence in the IPGG premises, use of the IPGG technological platform, collaboration between IPGG teams, linked to an IPGG doctoral or postdoctoral grant, or use of the common spaces), you must indicate the following sentence : "This work has received the support of "Institut Pierre-Gilles de Gennes" (laboratoire d'excellence, "Investissements d'avenir" program ANR-10-IDEX-0001-02 PSL and ANR-10-LABX-31.) ".

- For any publication of results obtained through the use of equipment purchased by the Equipex IPGG, you must add the following coding: "ANR-10-EQPX-34".

3 publications.