出版社：American Society for Biochemistry and Molecular Biology
摘要：Receptor activation leads to the dynamic remodeling of the plasmamembrane. Previous work using immunoelectron microscopy showedthat aggregated high-affinity receptor for immunoglobulin E(FcRI) and aggregated Thy-1, a glycerophosphoinositol (GPI)-anchoredprotein, have distinct membrane distributions. We now reportlipidomics analysis of FcRI- and Thy-1-enriched vesicles obtainedby magnetic bead isolation in the absence of detergent. Proteinanalyses show that FcRI domains are enriched in receptors andassociated signaling molecules, whereas Thy-1 domains are devoidof FcRI subunits. Positive and negative ion electrospray massspectrometry demonstrated that both domains retained a complexmixture of phospholipid classes and molecular species, predominantlyglycerophosphocholine, glycerophosphoethanolamine (GPE), andsphingomyelin as well as glycerophosphoserine and GPI lipids.Analysis of total acyl groups showed that <50% of fatty acidsin these domains are fully saturated, inconsistent with therecruitment of aggregated receptors or GPI-anchored proteinsto liquid ordered domains. However, further analysis showedthat FcRI domains contain two times more sphingomyelin and ahigh ratio of cholesterol to total fatty acid content comparedwith Thy 1-enriched domains. Remarkably, plasmenyl glycerophosphoethanolaminephospholipids (plasmalogen GPE) were also 2.5–3 timesmore abundant in FcRI domains than in the Thy-1 microdomains,whereas most diacyl GPE molecular species were equally abundantin the two domains.Supplementary key words lipidomics • membrane microdomains • lipid rafts • immunoglobulin E receptor • glycerophosphoinositol-anchored proteins
Abbreviations: DRM, detergent-resistant membrane; ESI, electrospray ionization; FcRI, high-affinity receptor for immunoglobulin E; GPC, glycerophosphocholine; GPE, glycerophosphoethanolamine; GPI, glycerophosphoinositol; GPS, glycerophosphoserine; MßCD, methyl-ß-cyclodextrin; MS/MS, tandem mass spectrometry
RI) and aggregated Thy-1, a glycerophosphoinositol (GPI)-anchored protein, have distinct membrane distributions. We now report lipidomics analysis of Fc
