LPS induces CD14 association with complement receptor type 3, which is reversed by neutrophil adhesion.
CD14, a glycosylphosphatidyl inositol (GPI)-linked membrane protein, is a key membrane binding site for LPS (endotoxin). Although CD14 lacks transmembrane and cytoplasmic sequences, it activates CR3-mediated leukocyte adhesion and cytokine release. Since CR3 has been shown to interact with other GPI-linked membrane proteins, we tested the hypothesis that CD14 can physically associate with CR3. Using qualitative and quantitative resonance energy transfer microscopy, we show that LPS in the presence of serum or LPS binding protein triggers formation of CD14-CR3 complexes. Kinetic studies show that CD14-CR3 complexes dissociate as neutrophils attach to substrates. We speculate that LPS-charged CD14 enhances CR3-mediated adhesion by directly binding to CR3.
Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
D M
DM
Zarewych
A L
AL
Kindzelskii
R F
RF
Todd
H R
HR
Petty
D000328:Adult; D002448:Cell Adhesion; D002462:Cell Membrane / Q000378:metabolism; D004731:Endotoxins / Q000378:metabolism / Q000494:pharmacology*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D018950:Lipopolysaccharide Receptors / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000378:metabolism / Q000494:pharmacology*; D046911:Macromolecular Substances; D008856:Microscopy, Fluorescence; D009504:Neutrophils / Q000166:cytology*; D017463:Receptors, Complement 3b / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*
D004731:Endotoxins; D017261:Glycosylphosphatidylinositols; D018950:Lipopolysaccharide Receptors; D008070:Lipopolysaccharides; D046911:Macromolecular Substances; D017463:Receptors, Complement 3b; D011971:Receptors, Immunologic; C048071:endotoxin receptor; C044101:endotoxin, Escherichia coli