Spatial Raft Coalescence Represents an Initial Step in FcγR Signaling

Fas signaling induces raft coalescence that is blocked by cholesterol depletion in human RPE cells undergoing apoptosis.

PURPOSE To investigate whether the signaling events occurring in Fas-mediated apoptosis alter raft membrane formation in human RPE cells. METHODS Formation of lipid rafts in cultured human retinal pigment epithelial cells (ARPE-19) was studied by confocal microscopy, with fluorescein-labeled cholera toxin subunit B binding protein (BODIPY)-labeled ganglioside GM1 lipid after Fas-L induction o...

Lipid Raft-Associated GTPase Signaling

Carbohydrate-carbohydrate interaction as an initial step in cell recognition

Specific interaction between specific carbohydrate moieties of glycosphingolipids (GSLs) has been demonstrated based on interaction of GSLcontaining liposomes with GSL-coated solid phase, and affinity adsorption of multivalent GSL oligosaccharide on solid-phase GSL column. Evidence is presented that such GSL-GSL interaction is an initial step in the cell recognition process. Examples are LeX-Le...

Coalescence of B cell receptor and invariant chain MHC II in a raft-like membrane domain.

The BCR binds antigen for processing and subsequent presentation on MHC II molecules. Polyvalent antigen induces BCR clustering and targeting to endocytic processing compartments, which are also accessed by Ii-MHC II. Here, we report that clustered BCR is able to team up with Ii-MHC II already at the plasma membrane of mouse B-lymphocytes. Colocalization of BCR and Ii-MHC II on the cell surface...

Erythropoietin Receptor Signaling Is Membrane Raft Dependent

Upon erythropoietin (Epo) engagement, Epo-receptor (R) homodimerizes to activate JAK2 and Lyn, which phosphorylate STAT5. Although recent investigations have identified key negative regulators of Epo-R signaling, little is known about the role of membrane localization in controlling receptor signal fidelity. Here we show a critical role for membrane raft (MR) microdomains in creation of discret...