lipid droplets; Saccharomyces cerevisiae; topology of lipid synthesis; endoplasmic reticulum; CAP proteins; lipid homeostasis; sterol-binding proteins; cholesterol
Choudhary V, Schneiter R (2020), Lipid droplet biogenesis from specialized ER subdomain., in Microbial Cell
, 7, 218-221.
Zoni V, Khaddaj R, Campomanes P, Thiam AR, Schneiter R, Vanni S (2020), Lipid droplet biogenesis is driven by liquid-liquid phase separation.., in Submitted
Dawoody Nejad L, Stumpe M, Rauch M, Hemphill A, Schneiter R, Bütikofer P, Serricchio M (2020), Mitochondrial sphingosine-1-phosphate lyase is essential for phosphatidylethanolamine synthesis and survival of Trypanosoma brucei., in Sci Rep
, 10(1), 8268-8268.
El Atab O, Darwiche R, Truax NJ, Schneiter R, Hull KG, Romo D, Asojo OA (2020), Necator americanus Ancylostoma secreted protein-2 (Na-ASP-2) selectively binds an ascaroside (ascr#3), in Int. J. Parasit
Choudhary V, El Atab O, Mizzon G, Prinz WA, Schneiter R (2020), Seipin and Nem1 establish discrete ER subdomains to initiate yeast lipid droplet biogenesis., in J. Cell. Biol.
, 219(7), e201910177.
Khaddaj R, Mari M, Cottier S, Reggiori F, Schneiter R (2020), Targeting of integral membrane proteins to the surface of lipid droplets., in Submitted
, Submitted, submitted.
Cottier S, Darwiche R, Meyenhofer F, Debelyy MO, Schneiter R (2020), The yeast cell wall protein Pry3 inhibits mating through highly conserved residues within the CAP domain., in Biol Open
, 9, bio053470.
Choudhary V, Golani G, Joshi AS, Cottier S, Schneiter R, Prinz WA, Kozlov MM (2018), Architecture of Lipid Droplets in Endoplasmic Reticulum Is Determined by Phospholipid Intrinsic Curvature., in Current Biology
, 28, 915-926e9.
Darwiche R, Lugo F, Drurey C, Varossieau K, Smant G, Wilbers RHP, Maizels RM, Schneiter R, Asojo OA (2018), Crystal structure of Brugia malayi venom allergen-like protein-1 (BmVAL-1), a vaccine candidate for lymphatic filariasis., in Int. J. Parasit.
, 48(5), 371-378.
Asojo OA, Darwiche R, Gebremedhin S, Smant G, Lozano-Torres JL, Drurey C, Pollet J, Maizels RM, Schneiter R, Wilbers RHP (2018), Heligmosomoides polygyrus Venom Allergen-like Protein-4 (HpVAL-4) is a sterol binding protein., in Int. J. Parasit.
, 48(5), 359-369.
Bantel Y, Darwiche R, Rupp S, Schneiter R, Sohn K (2018), Localization and functional characterization of the pathogenesis-related proteins Rbe1p and Rbt4p in Candida albicans., in PLoS One
, 13(8), 0201932-0201932.
Wilbers RHP, Schneiter R, Holterman MHM, Drurey C, Smant G, Asojo OA, Maizels RM, Lozano-Torres JL (2018), Secreted venom allergen-like proteins of helminths: Conserved modulators of host responses in animals and plants., in PLoS Pathog
, 14(10), 1007300-1007300.
Darwiche R, Schneiter R (2017), A Ligand-Binding Assay to Measure the Affinity and Specificity of Sterol-Binding Proteins In Vitro., in Methods Mol Biol
, 1645, 361-368.
Debelyy MO, Waridel P, Quadroni M, Schneiter R, Conzelmann A (2017), Chemical crosslinking and mass spectrometry to elucidate the topology of integral membrane proteins., in PLoS One
, 12(10), 0186840-0186840.
Luo Z, Kelleher AJ, Darwiche R, Hudspeth EM, Shittu OK, Krishnavajhala A, Schneiter R, Lopez JE, Asojo OA (2017), Crystal Structure of Borrelia turicatae protein, BTA121, a differentially regulated gene in the tick-mammalian transmission cycle of relapsing fever spirochetes., in Sci Rep
, 7(1), 15310-15310.
Baroni RM, Luo Z, Darwiche R, Hudspeth EM, Schneiter R, Pereira GAG, Mondego JMC, Asojo OA (2017), Crystal Structure of MpPR-1i, a SCP/TAPS protein from Moniliophthora perniciosa, the fungus that causes Witches' Broom Disease of Cacao., in Sci Rep
, 7(1), 7818-7818.
Darwiche R, El Atab O, Baroni RM, Teixeira PJPL, Mondego JMC, Pereira GAG, Schneiter R (2017), Plant pathogenesis-related proteins of the cacao fungal pathogen Moniliophthora perniciosa differ in their lipid-binding specificities., in J. Biol. Chem.
, 292(50), 20558-20569.
Knupp J, Martinez-Montañés F, Van Den Bergh F, Cottier S, Schneiter R, Beard D, Chang A (2017), Sphingolipid accumulation causes mitochondrial dysregulation and cell death., in Cell Death Differ
, 24, 2044-2053.
Darwiche R, El Atab O, Cottier S, Schneiter R (2017), The function of yeast CAP family proteins in lipid export, mating, and pathogen defense., in FEBS Lett
, 592(8), 1304-1311.
Darwiche R, Mène-Saffrané L, Gfeller D, Asojo OA, Schneiter R (2017), The pathogen-related yeast protein Pry1, a member of the CAP protein superfamily, is a fatty acid-binding protein., in J. Biol. Chem.
, 292(20), 8304-8314.
Gamir J, Darwiche R, Van't Hof P, Choudhary V, Stumpe M, Schneiter R, Mauch F (2017), The sterol-binding activity of PATHOGENESIS-RELATED PROTEIN 1 reveals the mode of action of an antimicrobial protein., in Plant J
, 89(3), 502-509.
This research program addresses two separate topics: the biogenesis of lipid droplets and their association with the membrane of the endoplasmic reticulum, and the structure and function of an important and widespread protein superfamily, known as CAP proteins. Lipid droplets are present in all eukaryotic cells and are discernible as round intracellular structures. They serve to store metabolic energy in form of neutral lipids, commonly known as “fat”. This energy is stored primarily in the fatty acids that are esterified in triacylglycerols and steryl esters, and is released upon ?-oxidation of these fatty acids. Lipid droplets are thus implicated in many of the pandemic diseases such as obesity, insulin resistance, atherosclerosis and lipotoxicity. The hydrophobic core of lipid droplets is covered by a phospholipid monolayer and they harbor a specific set of proteins, many of which function in neutral lipid metabolism, such as lipases or acyltransferases. We and others have previously shown that these lipid droplets are closely associated with the membrane of the endoplasmic reticulum. This association is functionally important as it allows the transfer of integral membrane as well as that of lipids between the two compartments. The precise nature of this association between the two compartments, however, has remained elusive. Recent results from our laboratory indicate that lipid droplets are accessible to proteins from within the luminal compartment of the endoplasmic reticulum, indicating that lipid droplets may form inside this luminal compartment. Should this indeed be the case, the biogenesis of lipid droplets would be similar to that of lipoprotein particles, which in essence are a functionalized, secreted form of lipid droplets. The aim of this part of the proposal thus is to define the nature of the association between the endoplasmic reticulum and lipid droplets. Therefore, we will determine whether endoplasmic reticulum resident integral membrane proteins can laterally move to localize over lipid droplets. In addition, we will compare the structure and topology of integral membrane proteins between their localization in the endoplasmic reticulum and their lipid droplet localization. The results of this study will thus provide new essential information to define and understand how exactly proteins and lipids can be exchanged between the endoplasmic reticulum and the lipid droplet storage compartment. This information is essential for an improved understanding of the etiology of lipid-related diseases.The CAP superfamily of proteins is named after the three founding members of this family, Cysteine-rich secretory proteins (CRISP), Antigen 5, and Pathogenesis-related 1 (PR-1). CAP family members are implicated in many fundamental biological processes, ranging from immune defense in mammals and plants, sperm maturation and fertilization, pathogen virulence, venom toxicity and even prostate and brain cancer. CAP family members are mostly secreted glycoproteins that are stable in the extracellular space. The mode of action of these proteins, however, has remained elusive. We could previously show that the CAP family members in yeast, known as Pathogen Related in Yeast (Pry), bind and thereby solubilize sterols and related hydrophobic compounds. Sterol binding is a conserved feature of many CAP proteins, including human CRISP2, a CAP superfamily member that is expressed in the testis and epididymis and participates in sperm-egg interaction during fertilization, and the plant PR-1 protein, which is synthesized in response to infections of plants with pathogens. Recent evidence indicates that these proteins not only are capable of binding sterols, but they independently also can bind fatty acids. We will test whether Pry proteins bind fatty acids, define the binding site by site-directed mutagenesis and test whether lipid binding of these proteins is important for their membrane association, permeabilization, and in vivo function. These results will thus help to define the molecular mode of action of these proteins and thereby improve our understanding of the physiological function these proteins exert in both health and disease.