Signaling through ZAP-70 is required for CXCL12-mediated T-cell transendothelial migration.
Transendothelial migration of activated lymphocytes from the blood into the tissues is an essential step for immune functions. The housekeeping chemokine CXCL12 (or stroma cell-derived factor-1alpha), a highly efficient chemoattractant for T lymphocytes, drives lymphocytes to sites where they are highly likely to encounter antigens. This suggests that cross-talk between the T-cell receptor (TCR) and CXCR4 (the CXCL12 receptor) might occur within these sites. Here we show that the zeta-associated protein 70 (ZAP-70), a key element in TCR signaling, is required for CXCR4 signal transduction. The pharmacologic inhibition of ZAP-70, or the absence of ZAP-70 in Jurkat T cells and in primary CD4(+) T cells obtained from a patient with ZAP deficiency, resulted in an impairment of transendothelial migration that was rescued by the transfection of ZAP-70. Moreover, the overexpression of mutated forms of ZAP-70, whose kinase domain was inactivated, also abrogated the migratory response of Jurkat T cells to CXCL12. In contrast, no involvement of ZAP-70 in T-cell arrest on inflammatory endothelium under flow conditions or in CXCL12-induced actin polymerization was observed. Furthermore, CXCL12 induced time-dependent phosphorylation of ZAP-70, Vav1, and extracellular signal-regulated kinases (ERKs); the latter were reduced in the absence of functional ZAP-70. However, though a dominant-negative Vav1 mutant (Vav1 L213A) blocked CXCL12-induced T-cell migration, pharmacologic inhibition of the ERK pathway did not affect migration, suggesting that ERK activation is dispensable for T-cell chemotaxis. We conclude that cross-talk between the ZAP-70 signaling pathway and the chemokine receptor CXCR4 is required for T-cell migration.
Ticchioni
Michel
M
INSERM U343 and Laboratoire d'Immunologie, Hôpital de l'Archet, Nice, France.
Charvet
Céline
C
Noraz
Nelly
N
Lamy
Laurence
L
Steinberg
Marcos
M
Bernard
Alain
A
Deckert
Marcel
M
D015496:CD4-Positive T-Lymphocytes / Q000166:cytology; D002450:Cell Communication; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000166:cytology; D006801:Humans; D019169:Jurkat Cells; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011505:Protein-Tyrosine Kinases / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell / Q000172:deficiency / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology* / Q000201:enzymology / Q000276:immunology; D051746:ZAP-70 Protein-Tyrosine Kinase
C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; D015513:Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; C496618:VAV1 protein, human; D011505:Protein-Tyrosine Kinases; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; D020928:Mitogen-Activated Protein Kinases