SAP is an adaptor mutated in X-linked lymphoproliferative disease. It plays a critical role in T helper 2 (TH2) cytokine production. This function was suggested to reflect the capacity of SAP to associate with SLAM family receptors and enable tyrosine phosphorylation signaling by these receptors through SAP-mediated recruitment of Src-related kinase FynT. Here, we addressed by genetic means the importance of the SAP-FynT interaction in normal T cell functions. By creating a mouse in which the FynT binding site of SAP was inactivated in the germ line (sapR78A mouse) and by analyzing mice lacking SAP, FynT or SLAM, evidence was obtained that the SAP-FynT cascade is indeed crucial for normal TH2 functions in vitro and in vivo. These data imply that SAP is necessary for TH2 cytokine regulation primarily as a result of its capacity to recruit FynT. They also establish a previously unappreciated role for FynT in SAP-dependent TH2 cytokine regulation.
All Science Journal Classification (ASJC) codes
- Immunology and Allergy
- Infectious Diseases