Skip to main content
. 2020 Oct 29;8:589799. doi: 10.3389/fcell.2020.589799

FIGURE 1.

FIGURE 1

LacCer-enriched microdomain-mediated signaling and functions. (A) Typical lipid bilayer phase. (B) Structures of lactosylceramide and phosphatidylglucoside. Blue capital, electron acceptor atom. Red capital, electron donor atom. (C) Human neutrophils were incubated with Alexa546-anti LacCer monoclonal IgM at 4°C or 37°C for 15 min, and further incubated for 30 min on ice. After fixation, expression of LacCer on their cell surfaces was analyzed by flow cytometry (Iwabuchi et al., 2008). (D) The stained cells described in (C) were examined by confocal microscope, and 3D images were made by Imaris deconvolution software. (E) High performance thin layer chromatography analysis of LacCer in plasma membranes and granular membranes isolated from neutrophils and DHL60 cells (Iwabuchi et al., 2008). The C24-LacCer-containing upper band (C24) was missing from the plasma membranes of DHL60 cells. C16, C16-lacCer containing LacCer. Std, porcine blood-derived C24-LacCer enriched LacCer. PMN, plasma membranes of neutrophils. (F) In situ association of LacCer with Lyn on plasma membranes of neutrophils or DHL60 cells, as determined by immunoelectron microscopy of ultra thin cryo-sections prepared at ultra low temperature in the absence of organic solvents. Co-localization of LacCer (gray arrowheads) and Lyn (white arrowheads) in plasma membranes of human neutrophils, but not D-HL60 cells (Iwabuchi et al., 2008). Loading of C24:1- but not C16-LacCer onto D-HL60 cells resulted in co-localization of LacCer and Lyn, as in neutrophils. (G) Schematic illustration of the structural contexture of Lyn-coupled, LacCer-enriched microdomains. C24-LacCer molecules associated directly with Lyn, which is associated with the inner leaflets of cell membranes via palmitic chains, allowing LacCer-enriched microdomains to mediate neutrophil functions via Lyn. Crosslinking with the photoreactive 3H-LacCer analog indicates the presence of several C24-fatty acid chain-containing LacCer-associated proteins, including Lyn and Gαi small G protein (Chiricozzi et al., 2015).