sphingomyelin  (Croda International Plc)

Journal: bioRxiv

Article Title: Coupling between sterol and sphingolipid structure in ordered membrane domains

doi: 10.64898/2026.04.01.715929

Figure Lengend Snippet: ( A ) Canonical sterol-sphingolipid pairs in metazoans and fungi. Metazoan membranes are enriched in cholesterol and C16 sphingomyelin (SM), whereas fungal membranes contain ergosterol and very long chain (C26) inositol phosphoceramide (IPC). Structural features unique to ergosterol and IPC are highlighted in red. ( B ) Sphingolipid (SL) chain length distributions. Sphingomyelin in retinal pigment epithelial (RPE1) cells are enriched in C16 chains, whereas Saccharomyces cerevisiae sphingolipids are dominated by very long chain species (C26-C28). Lipidomic data is replotted from previous studies ( , ). ( C ) Schematic and representative fluorescence micrograph of vacuole membrane domains in WT yeast, showing micron-scale phase separation. ( D ) Disruption of sphingolipid elongation alters vacuole membrane organization. Sphingolipid acyl chains are extended from C16/C18 to C26 via Elo2 and Elo3. Deletion of ELO2 or ELO3 shortens sphingolipid chains and reduces micron-scale vacuole domains, as shown in representative micrographs and quantification in Fig. S1A. In contrast to elo2Δ cells, elo3Δ cells lack any C26 sphingolipids and show no domains. ( E ) Sterol structure also determines vacuole membrane organization. Lanosterol is a shared precursor in both metazoan and fungal sterol pathways. Ergosterol is synthesized from lanosterol through the ERG pathway, with Erg6 and Erg6 catalyzing key steps that generate fungal-specific structural features. Replacement of these enzymes with the metazoan counterparts DHCR24 and DHCR7 redirects the pathway to produce cholesterol, while upstream steps remain functionally compatible. Cells producing cholesterol instead of ergosterol fail to form vacuole membrane domains. For C-E, scale bars, 5 µm.

Article Snippet: 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DOPC), and Egg Sphingomyelin (eSM) were obtained from Avanti Polar Lipids.

Techniques: Fluorescence, Membrane, Disruption, Synthesized

Journal: bioRxiv

Article Title: Coupling between sterol and sphingolipid structure in ordered membrane domains

doi: 10.64898/2026.04.01.715929

Figure Lengend Snippet: ( A ) Representative micrographs of GUVs containing 25% sterol and increasing egg sphingomyelin (eSM). In ergosterol-containing membranes (top), fluid domains are maintained only at 25% eSM, whereas cholesterol-containing membranes (bottom) support fluid domains across a broader eSM range. ( B ) Substitution with very-long-chain C26-SM induces phase separation and solid-like behavior in ergosterol, but not cholesterol. Scale bars, 5 µm.

Article Snippet: 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DOPC), and Egg Sphingomyelin (eSM) were obtained from Avanti Polar Lipids.

Techniques:

Journal: bioRxiv

Article Title: Coupling between sterol and sphingolipid structure in ordered membrane domains

doi: 10.64898/2026.04.01.715929

Figure Lengend Snippet: ( A ) Laurdan generalized polarization (GP) as a function of temperature for 80/20 eSM/sterol mixtures containing cholesterol or ergosterol. Membranes display sterol-dependent differences in membrane order, with cholesterol systems showing a higher ordering and T misc . ( B ) Laurdan GP as a function of temperature for 80/20 C26-SM mixtures containing cholesterol or ergosterol. The C26-SM membranes exhibit elevated transition midpoints relative to eSM but eliminated T misc differences between cholesterol and ergosterol. ( C ) Interaction between sphingomyelin and sterols for Laurdan GP at 30 °C, the optimal growth temperature for yeast. In eSM membranes, ergosterol lowers GP relative to cholesterol whereas C26-SM membranes show minimal sterol-dependent packing change at this temperature. ( D ) Laurdan GP at 30°C plotted against the transition midpoint (T misc ) across compositions. The C26-SM systems show an elevated T misc , but a lack of Laurdan GP difference.

Article Snippet: 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DOPC), and Egg Sphingomyelin (eSM) were obtained from Avanti Polar Lipids.

Techniques: Membrane