Lineage-specific requirement for the PH domain of Vav1 in the activation of CD4+ but not CD8+ T cells.
Vav1 is a guanine nucleotide exchange factor (GEF) for Rho-family GTPases, which is activated by tyrosine phosphorylation following TCR stimulation. Vav1-deficient mice have defects in positive and negative selection of thymocytes as well as TCR-induced proliferation in mature T cells, demonstrating a critical role for Vav1 in transducing TCR signals. Binding of phospholipids to the PH domain of Vav1 has been proposed to regulate its GEF activity in vitro. To test this model in vivo, we have generated mice carrying a point mutation in the PH domain of Vav1, and we show that they have defects in T cell development and activation. We demonstrate that the mutation affects the function of Vav1 as a GEF and perturbs PI3K-dependent pathways downstream of Vav1. Unexpectedly, the mutation selectively affects TCR-induced proliferation of CD4(+) but not CD8(+) T cells, demonstrating differences in the wiring of TCR signaling pathways between the two lineages.
Prisco
Antonella
A
Division of Immune Cell Biology, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK.
Vanes
Lesley
L
Ruf
Sandra
S
Trigueros
Cesar
C
Tybulewicz
Victor L J
VL
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000276:immunology*; D002454:Cell Differentiation / Q000276:immunology; D019070:Cell Lineage / Q000276:immunology*; D049109:Cell Proliferation; D005434:Flow Cytometry; D015151:Immunoblotting; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation; D019869:Phosphatidylinositol 3-Kinases / Q000276:immunology / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000276:immunology*; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism
D018797:Cell Cycle Proteins; D011518:Proto-Oncogene Proteins; D051567:Proto-Oncogene Proteins c-vav; D011948:Receptors, Antigen, T-Cell; C496619:Vav1 protein, mouse; D019869:Phosphatidylinositol 3-Kinases