Stromal cell-derived factor-1alpha/CXCL12-induced chemotaxis of T cells involves activation of the RasGAP-associated docking protein p62Dok-1.
Events mediating stromal cell-derived factor-1 (SDF-1alpha/CXCL12) chemotaxis of lymphocytes are not completely known. We evaluated intracellular signaling through RasGAP-associated protein p62Dok-1 (downstream of tyrosine kinase [Dok-1]) and associated proteins. SDF-1alpha/CXCL12 stimulated Dok-1 tyrosine phosphorylation and association with RasGAP, adaptor protein p46Nck, and Crk-L in Jurkat T cells. The phosphorylation of Dok-1 was blocked by pretreatment of cells with the src kinase inhibitor PP2. Src kinase family member Lck was implicated. SDF-1alpha/CXCL12 did not phosphorylate Dok-1 in J.CaM1.6 cells, a Jurkat derivative not expressing Lck, but did phosphorylate Dok-1 in J.CaM1.6 cells expressing Lck. SDF-1alpha/CXCL12 induced the tyrosine phosphorylation of Pyk2 and the association of Pyk2 with zeta chain-associated protein-70 kilodaltons (Zap-70) and Vav. SDF-1alpha/CXCL12 enhanced the association of RasGAP with Pyk2. CXCR4-expressing NIH3T3 and Baf3 cells transfected with full-length Dok-1 cDNA were suppressed in their responses to SDF-1alpha/CXCL12-induced chemotaxis; mitogen-activated protein (MAP) kinase activity was also decreased. Chemotaxis to SDF-1/CXCL12 was significantly enhanced in Dok-1(-/-) CD4+ and CD8+ splenic T cells. These results implicate Dok-1, Nck, Crk-L, and Src kinases-especially Lck, Pyk2, Zap-70, Vav, and Ras-GAP-in intracellular signaling by SDF-1alpha/CXCL12, and they suggest that Dok-1 plays an important role in SDF-1alpha/CXCL12-induced chemotaxis in T cells.
Okabe
Seiichi
S
Department of Microbiology/Immunology and the Walther Oncology Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
Fukuda
Seiji
S
Kim
Young-June
YJ
Niki
Masaru
M
Pelus
Louis M
LM
Ohyashiki
Kazuma
K
Pandolfi
Pier Paolo
PP
Broxmeyer
Hal E
HE
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D051418:Focal Adhesion Kinase 2; D006801:Humans; D019169:Jurkat Cells; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000378:metabolism; D015513:Oncogene Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D051567:Proto-Oncogene Proteins c-vav; D016601:RNA-Binding Proteins / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology* / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase; D020703:ras GTPase-Activating Proteins / Q000378:metabolism; D019061:src-Family Kinases / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; C082869:CRKL protein; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D004268:DNA-Binding Proteins; C489560:DOK1 protein, human; C078332:Nck protein; D009687:Nuclear Proteins; D015513:Oncogene Proteins; D010750:Phosphoproteins; D051567:Proto-Oncogene Proteins c-vav; D016601:RNA-Binding Proteins; C496618:VAV1 protein, human; C496619:Vav1 protein, mouse; D020703:ras GTPase-Activating Proteins; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C496053:Ptk2b protein, mouse; D051746:ZAP-70 Protein-Tyrosine Kinase; C497261:ZAP70 protein, human; C497262:Zap70 protein, mouse; D019061:src-Family Kinases