The Vav binding site of the non-receptor tyrosine kinase Syk at Tyr 348 is critical for beta2 integrin (CD11/CD18)-mediated neutrophil migration.
Leukocyte adhesion via beta(2) integrins (CD11/CD18) activates the tyrosine kinase Syk. We found that Syk was enriched at the lamellipodium during N-formyl-Met-Leu-Phe-induced migration of neutrophil-like differentiated HL-60 cells. Here, Syk colocalized with Vav, a guanine nucleotide exchange factor for Rac and Cdc42. The enrichment of Syk at the lamellipodium and its colocalization with Vav were absent upon expression of a Syk kinase-dead mutant (Syk K402R) or a Syk mutant lacking the binding site of Vav (Syk Y348F). Live cell imaging revealed that both mutations resulted in excessive lamellipodium formation and severely compromised migration compared with control cells. Similar results were obtained upon down-regulation of Syk by RNA interference (RNAi) technique as well as in Syk(-/-) neutrophils from wild-type mice reconstituted with Syk(-/-) bone marrow. A pivotal role of Syk in vivo was demonstrated in the Arthus reaction, where neutrophil extravasation, edema formation, and hemorrhage were profoundly diminished in Syk(-/-) bone marrow chimeras compared with those in control animals. In the inflamed cremaster muscle, Syk(-/-) neutrophils revealed a defect in adhesion and migration. These findings indicate that Syk is critical for beta(2) integrin-mediated neutrophil migration in vitro and plays a fundamental role in neutrophil recruitment during the inflammatory response in vivo.
Schymeinsky
Jurgen
J
Department of Physiology, Ludwig-Maximilians-Universität München, Schillerstr. 44, D-80336 München, Germany.
Sindrilaru
Anca
A
Frommhold
David
D
Sperandio
Markus
M
Gerstl
Ronald
R
Then
Cornelia
C
Mócsai
Attila
A
Scharffetter-Kochanek
Karin
K
Walzog
Barbara
B
D000818:Animals; D001183:Arthus Reaction / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D018845:CD11 Antigens / Q000235:genetics / Q000378:metabolism*; D018821:CD18 Antigens / Q000235:genetics / Q000378:metabolism*; D002465:Cell Movement / Q000187:drug effects / Q000235:genetics; D018922:HL-60 Cells; D006801:Humans; D066298:In Vitro Techniques; D007249:Inflammation / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000172:deficiency / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009363:Neoplasm Proteins; D020556:Neutrophil Infiltration / Q000235:genetics; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism*; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000235:genetics / Q000378:metabolism; D000072377:Syk Kinase; D020764:cdc42 GTP-Binding Protein / Q000378:metabolism
D018845:CD11 Antigens; D018821:CD18 Antigens; D047908:Intracellular Signaling Peptides and Proteins; D009363:Neoplasm Proteins; D051567:Proto-Oncogene Proteins c-vav; D009240:N-Formylmethionine Leucyl-Phenylalanine; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; C000606897:Syk protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D020764:cdc42 GTP-Binding Protein