cytochalasin-d and Encephalitis

The precise mechanism by which ICAM-1 transduces signals from adherent lymphocytes remains elusive. The ERM proteins ezrin and moesin were found to strongly co-localise with both ICAM-1 and F-actin in brain microvascular endothelial cells suggesting a potential role in mediating ICAM-1 signalling. Such strong co-localisation was maintained following treatment of cells with cytochalasin D, which inhibits actin polymerization and which is capable of inhibiting ICAM-1-induced signalling. Cross-linking of ICAM-1 demonstrated ICAM-1 clustering which no longer associated with ezrin or moesin. In addition immunoprecipitation analysis revealed that ICAM-1 was incapable of precipitating ERM proteins under conditions where ezrin was efficiently precipitated with anti-ICAM-2 antibodies. Fractionation of cell lysates on sucrose density gradients shows ICAM-1 and ezrin to sediment at different densities, whereas ICAM-2 co-sediments with ezrin. Together these data suggest that ICAM-1 is not directly associated with ezrin and moesin in brain microvascular endothelial cells.

Topics: Actins; Animals; Antigens, CD; Blood Proteins; Blood-Brain Barrier; Brain; Cell Adhesion; Cell Adhesion Molecules; Cells, Cultured; Chemotaxis, Leukocyte; Cytochalasin D; Cytoskeletal Proteins; Cytoskeleton; Encephalitis; Endothelium, Vascular; Immunologic Surveillance; Intercellular Adhesion Molecule-1; Membrane Proteins; Microfilament Proteins; Nucleic Acid Synthesis Inhibitors; Phosphoproteins; Precipitin Tests; Rats; rho GTP-Binding Proteins; Signal Transduction; Vinculin