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J. Cell Biol.,
Volume 142, Number 5, September 7, 1998 1371-1379
Division of Cell Biology, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
The ZAP-70 tyrosine kinase is essential for
T cell activation by the T cell receptor. We show that
ZAP-70 is also required for migration of T cells that
is dependent on the integrin LFA-1. Invasion of
TAM2D2 T cell hybridoma cells into fibroblast monolayers, which is LFA-1-dependent, was blocked by
overexpression of dominant-negative ZAP-70 and by
piceatannol but not by herbimycin A. The Syk inhibitor piceatannol blocks the Syk homologue ZAP-70, which
is expressed by TAM2D2 cells, with the same dose dependence as the inhibition of invasion. Dominant-negative ZAP-70 completely inhibited the extensive metastasis formation of TAM2D2 cells to multiple organs upon i.v. injection into mice. Migration of TAM2D2
cells through filters coated with the LFA-1 ligand
ICAM-1, induced by 1 ng/ml of the chemokine SDF-1,
was blocked by anti-LFA-1 mAb and also abrogated
by dominant-negative ZAP-70 and piceatannol. In contrast, migration induced by 100 ng/ml SDF-1 was independent of both LFA-1 and ZAP-70. LFA-1 cross-linking induced tyrosine phosphorylation, which was
blocked by dominant-negative ZAP-70 and piceatannol. We conclude that LFA-1 engagement triggers
ZAP-70 activity that is essential for LFA-1-dependent
migration.
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