Signaling functions of L-selectin in neutrophils: alterations in the cytoskeleton and colocalization with CD18

SI Simon, V Cherapanov, I Nadra… - The Journal of …, 1999 - journals.aai.org
SI Simon, V Cherapanov, I Nadra, TK Waddell, SM Seo, Q Wang, CM Doerschuk…
The Journal of Immunology, 1999journals.aai.org
Ligation and clustering of L-selectin by Ab (“cross-linking”) or physiologic ligands results in
activation of diverse responses that favor enhanced microvascular sequestration and
emigration of neutrophils. The earliest responses include a rise in intracellular calcium,
enhanced tyrosine phosphorylation, and activation of extracellular signal-regulated kinases.
Additionally, cross-linking of L-selectin induces sustained shape change and activation of β
2 integrins, leading to neutrophil arrest under conditions of shear flow. In this report, we …
Abstract
Ligation and clustering of L-selectin by Ab (“cross-linking”) or physiologic ligands results in activation of diverse responses that favor enhanced microvascular sequestration and emigration of neutrophils. The earliest responses include a rise in intracellular calcium, enhanced tyrosine phosphorylation, and activation of extracellular signal-regulated kinases. Additionally, cross-linking of L-selectin induces sustained shape change and activation of β 2 integrins, leading to neutrophil arrest under conditions of shear flow. In this report, we examined several possible mechanisms whereby transmembrane signals from L-selectin might contribute to an increase in the microvascular retention of neutrophils and enhanced efficiency of emigration. In human peripheral blood neutrophils, cross-linking of L-selectin induced alterations in cellular biophysical properties, including a decrease in cell deformability associated with F-actin assembly and redistribution, as well as enhanced adhesion of microspheres bound to β 2 integrins. L-selectin and the β 2 integrin became spatially colocalized as determined by confocal immunofluorescence microscopy and fluorescence resonance energy transfer. We conclude that intracellular signals from L-selectin may enhance the microvascular sequestration of neutrophils at sites of inflammation through a combination of cytoskeletal alterations leading to cell stiffening and an increase in adhesiveness mediated through alterations in β 2 integrins.
journals.aai.org