title: FcepsilonRI and Thy-1 domains have unique protein and lipid compositions.
abstract: Receptor activation leads to the dynamic remodeling of the plasma membrane. Previous work using immunoelectron microscopy showed that aggregated high-affinity receptor for immunoglobulin E (FcRI) and aggregated Thy-1, a glycerophosphoinositol (GPI)-anchored protein, have distinct membrane distributions. We now report lipidomics analysis of FcRI- and Thy-1-enriched vesicles obtained by magnetic bead isolation in the absence of detergent. Protein analyses show that FcRI domains are enriched in receptors and associated signaling molecules, whereas Thy-1 domains are devoid of FcRI subunits. Positive and negative ion electrospray mass spectrometry demonstrated that both domains retained a complex mixture of phospholipid classes and molecular species, predominantly glycerophosphocholine, glycerophosphoethanolamine (GPE), and sphingomyelin as well as glycerophosphoserine and GPI lipids. Analysis of total acyl groups showed that < 50% of fatty acids in these domains are fully saturated, inconsistent with the recruitment of aggregated receptors or GPI-anchored proteins to liquid ordered domains. However, further analysis showed that FcRI domains contain two times more sphingomyelin and a high ratio of cholesterol to total fatty acid content compared with Thy 1-enriched domains. Remarkably, plasmenyl glycerophosphoethanolamine phospholipids (plasmalogen GPE) were also 2.5-3 times more abundant in FcRI domains than in the Thy-1 microdomains, whereas most diacyl GPE molecular species were equally abundant in the two domains.
authors: Department of Pathology, University of New Mexico, Albuquerque, NM, USA.
authors: Zurab
authors: Z
authors: Surviladze
authors: Kathleen A
authors: KA
authors: Harrison
authors: Robert C
authors: RC
authors: Murphy
authors: Bridget S
authors: BS
authors: Wilson
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D020552:Comet Assay; D005997:Glycerylphosphorylcholine / Q000737:chemistry / Q000378:metabolism; D017261:Glycosylphosphatidylinositols / Q000737:chemistry / Q000378:metabolism; D018189:Immunomagnetic Separation; D008563:Membrane Lipids / Q000737:chemistry / Q000378:metabolism*; D021962:Membrane Microdomains / Q000737:chemistry / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D010714:Phosphatidylethanolamines / Q000737:chemistry / Q000378:metabolism; D010768:Phosphoserine / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D017455:Receptors, IgE / Q000378:metabolism*; D021241:Spectrometry, Mass, Electrospray Ionization; D013109:Sphingomyelins / Q000737:chemistry / Q000378:metabolism; D018800:Thy-1 Antigens / Q000378:metabolism*
chemical_list: D017261:Glycosylphosphatidylinositols; D008563:Membrane Lipids; D008565:Membrane Proteins; D010714:Phosphatidylethanolamines; D017455:Receptors, IgE; D013109:Sphingomyelins; D018800:Thy-1 Antigens; C002449:glycerophosphoethanolamine; D010768:Phosphoserine; C067651:glycerophosphoserine; D005997:Glycerylphosphorylcholine