Abstract
In inflammation, neutrophils and other leukocytes roll along the microvascular endothelium before arresting and transmigrating into inflamed tissues. Arrest requires conformational activation of the integrin lymphocyte function-associated antigen-1 (LFA-1). Mutations of the FERMT3 gene encoding kindlin-3 underlie the human immune deficiency known as leukocyte adhesion deficiency-III. Both kindlin-3 and talin-1, another FERM domain-containing cytoskeletal protein, are required for integrin activation, but their individual roles in the induction of specific integrin conformers are unclear. Here, we induce differential LFA-1 activation in neutrophils through engagement of the selectin ligand P-selectin glycoprotein ligand-1 or the chemokine receptor CXCR2. We find that talin-1 is required for inducing LFA-1 extension, which corresponds to intermediate affinity and induces neutrophil slow rolling, whereas both talin-1 and kindlin-3 are required for induction of the high-affinity conformation of LFA-1 with an open headpiece, which results in neutrophil arrest. In vivo, both slow rolling and arrest are defective in talin-1-deficient neutrophils, whereas only arrest is defective in kindlin-3-deficient neutrophils. We conclude that talin-1 and kindlin-3 serve distinct functions in LFA-1 activation.
Publication types
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Comparative Study
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Bone Marrow Transplantation
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Cell Adhesion
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Chemotaxis, Leukocyte / physiology*
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Cytoskeletal Proteins / antagonists & inhibitors
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / physiology*
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Green Fluorescent Proteins / analysis
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HL-60 Cells
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Humans
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Intercellular Adhesion Molecule-1 / metabolism
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K562 Cells
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Lymphocyte Function-Associated Antigen-1 / chemistry
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Lymphocyte Function-Associated Antigen-1 / metabolism*
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Membrane Proteins / antagonists & inhibitors
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Membrane Proteins / genetics
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Membrane Proteins / physiology
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Mice
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Mice, Inbred C57BL
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Neoplasm Proteins / antagonists & inhibitors
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology
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Neutrophils / metabolism*
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Peritonitis / chemically induced
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Peritonitis / immunology
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Peritonitis / metabolism
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Protein Binding
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Protein Conformation
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RNA Interference
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RNA, Small Interfering / pharmacology
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Radiation Chimera
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Specific Pathogen-Free Organisms
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Talin / antagonists & inhibitors
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Talin / genetics
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Talin / physiology*
Substances
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Cytoskeletal Proteins
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FERMT3 protein, human
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Icam1 protein, mouse
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Lymphocyte Function-Associated Antigen-1
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Membrane Proteins
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Neoplasm Proteins
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RNA, Small Interfering
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TLN1 protein, human
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Talin
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kindlin-3 protein, mouse
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Tln1 protein, mouse
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Intercellular Adhesion Molecule-1
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Green Fluorescent Proteins