FcϵRI and Thy-1 domains have unique protein and lipid compositions

Zurab Surviladze, Kathleen A. Harrison, Robert C. Murphy, Bridget S. Wilson
2007 Journal of Lipid Research  
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 (FceRI) and aggregated Thy-1, a glycerophosphoinositol (GPI)-anchored protein, have distinct membrane distributions. We now report lipidomics analysis of FceRI-and Thy-1-enriched vesicles obtained by magnetic bead isolation in the absence of detergent. Protein analyses show that FceRI domains are enriched in
more » ... eceptors and associated signaling molecules, whereas Thy-1 domains are devoid of FceRI 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 FceRI 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 FceRI domains than in the Thy-1 microdomains, whereas most diacyl GPE molecular species were equally abundant in the two domains.-Surviladze, Z., K. A. Harrison, R. C. Murphy, and B. S. Wilson. FceRI and Thy-1 domains have unique protein and lipid compositions. J. Lipid Res. 2007Res. . 48: 1325Res. -1335
doi:10.1194/jlr.m600485-jlr200 pmid:17387221 fatcat:w6f3s7xz3zasvpmdoo6grdj7hq