Topographic requirements and dynamics of signaling via L-selectin on neutrophils

• Published in: American Journal of Physiology: Cell Physiology 2003-03, Vol.284 (3), p.C705-C717
• Main Authors: Green, Chad E, Pearson, David N, Christensen, Nadine B, Simon, Scott I
• Format: Article
• Language: English
• Subjects: CD18 Antigens - drug effects; CD18 Antigens - immunology; CD18 Antigens - metabolism; Cell Adhesion - drug effects; Cell Adhesion - immunology; Cell Adhesion Molecules - immunology; Chemotaxis, Leukocyte - drug effects; Chemotaxis, Leukocyte - immunology; Humans; L-Selectin - drug effects; L-Selectin - immunology; MAP Kinase Signaling System - drug effects; MAP Kinase Signaling System - physiology; Mitogen-Activated Protein Kinase 1 - drug effects; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinases - drug effects; Mitogen-Activated Protein Kinases - metabolism; Neutrophils - drug effects; Neutrophils - enzymology; Neutrophils - immunology; p38 Mitogen-Activated Protein Kinases; Phosphorylation - drug effects; Receptors, Cell Surface - drug effects; Receptors, Cell Surface - immunology; Signal Transduction - drug effects; Signal Transduction - immunology
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00331.2002

Department of Biomedical Engineering, University of California, Davis, California 95616 Cross-linking of L-selectin on leukocytes signals phosphorylation of mitogen-activated protein kinases (MAPKs) leading to activation of CD18 function and enhanced transmigration on inflamed endothelium. We examined how alterations in the topography of L-selectin correlate with the dynamics of CD18 activation and phosphorylation of MAPK. Simultaneous ligation of humanized antibodies DREG55 and DREG200 provided a strategy for regulating the extent of cross-linking. Triggering of CD11b/CD18 upregulation and adhesion required clustering of L-selectin to microvillus-sized patches of ~0.2 µm 2 . Immunofluorescence revealed that L-selectin was colocalized with high-affinity CD18. Anti-L-selectin-coated protein A microspheres indicated that a single site of contact to a 5.5-µm bead, or multiple contacts to 0.94- or 0.3-µm beads, elicited maximum neutrophil activation. Adhesion signaled via L-selectin coincided with the kinetics of MAPK phosphorylation and was inhibited by blocking p38 or p42/44 activity. These data demonstrate the capacity of L-selectin to transduce signals effecting rapid (~1 s) neutrophil adhesion that is regulated by the size and frequency of receptor clustering. protein kinases; adhesion molecules; antibodies; cellular activation