CD28 Costimulation: A Source of Vav-1 for TCR Signaling with the Help of SLP-76?
Frédérique Michel* and
Oreste Acuto
Molecular Immunology Unit, Department of Immunology, Institut Pasteur, 25, rue du Dr. Roux, 75724 Paris, Cedex 15, France.
Summary:
T cells require dual stimulation to become activated. When T cells encounter antigen-presenting cells, both the T cell receptor (TCR) and the CD28 coreceptor are ligated and activated. Michel and Acuto discuss how the adaptor SLP-76, which is recruited to the activated TCR complex, and the Rho family guanosine triphosphatase exchanger Vav-1, which is recruited by the CD28 receptor and TCR, may form a macromolecular complex that results in T cells activation. Vav-1 may serve as a central integrator between CD28 signaling and TCR signaling through its indirect effects on phosphoinositide 3-kinase-dependent signaling.
*Corresponding author. Telephone, 33-1-4568-8638; fax, 33-1-4061-3204; e-mail: fmichel{at}pasteur.fr
