title: Solubilization of glycosyl-phosphatidylinositol-anchored proteins in quiescent and stimulated neutrophils.
abstract: In human neutrophils, alkaline phosphatase (AlkPase), a low-affinity receptor for IgG (FcRIIIB), and complement decay accelerating factor (DAF) are glycosyl-phosphatidylinositol (GPI)-anchored proteins. Varying greatly in biological function these three integral membrane proteins exhibit regulated cell surface expression in neutrophils. Defined by their common membrane-linkage motif, AlkPase, FcRIIIB, and DAF can be released from the lipid bilayer by the action of phosphatidylinositol-specific phospholipase C and are relatively resistant to low temperature extraction with Triton X-100 (TX-100). In this study we show that neutrophil AlkPase, FcRIII, and DAF display differential extractibility; they are relatively insensitive to TX-100 solubilization at 4 degrees C, but are readily extracted with TX-100 at 37 degrees C or by the detergent octyl glucoside at 4 degrees C. The differential extractibility of these GPI-anchored proteins is the same in unstimulated cells, where these proteins exist primarily in an intracellular pool, and stimulated cells, where they are expressed principally at the cell surface. However, no differential extraction effect is observed with two neutrophil transmembrane proteins, complement receptor 1 (CD35, CR1) and MHC Class I in either stimulated or unstimulated cells.
authors.affiliation: Department of Cell Biology, Neurobiology and Anatomy, Ohio State University, College of Medicine, Columbus 43210, USA.
authors.forename: T J
authors.initials: TJ
authors.lastname: Cain
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.forename: T
authors.initials: T
authors.lastname: Takizawa
authors.forename: J M
authors.initials: JM
authors.lastname: Robinson
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000737:chemistry*; D015703:Antigens, CD / Q000737:chemistry*; D018958:CD55 Antigens; D017261:Glycosylphosphatidylinositols / Q000737:chemistry*; D015395:Histocompatibility Antigens Class I / Q000737:chemistry; D006801:Humans; D008297:Male; D008562:Membrane Glycoproteins / Q000737:chemistry*; D018375:Neutrophil Activation; D009504:Neutrophils / Q000737:chemistry* / Q000276:immunology; D017463:Receptors, Complement 3b / Q000737:chemistry; D017452:Receptors, IgG / Q000737:chemistry*; D012995:Solubility
chemical_list: D015703:Antigens, CD; D018958:CD55 Antigens; D017261:Glycosylphosphatidylinositols; D015395:Histocompatibility Antigens Class I; D008562:Membrane Glycoproteins; D017463:Receptors, Complement 3b; D017452:Receptors, IgG; D000469:Alkaline Phosphatase