| First Author | Sathish JG | Year | 2004 |
| Journal | J Biol Chem | Volume | 279 |
| Issue | 46 | Pages | 47783-91 |
| PubMed ID | 15364920 | Mgi Jnum | J:118518 |
| Mgi Id | MGI:3699701 | Doi | 10.1074/jbc.M402354200 |
| Citation | Sathish JG, et al. (2004) CD22 is a functional ligand for SH2 domain-containing protein-tyrosine phosphatase-1 in primary T cells. J Biol Chem 279(46):47783-91 |
| abstractText | The intracellular Src homology 2 (SH2) domain-containing protein-tyrosine phosphatase (SHP-1) has been characterized as a negative regulator of T cell function, contributing to the definition of T cell receptor signaling thresholds in developing and peripheral mouse T lymphocytes. The activation of SHP-1 is achieved through the engagement of its tandem SH2 domains by tyrosine-phosphorylated proteins; however, the identity of the activating ligand(s) for SHP-1, within mouse primary T cells, is presently unresolved. The identification of SHP-1 ligand(s) in primary T cells would provide crucial insight into the molecular mechanisms by which SHP-1 contributes to in vivo thresholds for T cell activation. Here we present a combination of biochemical and yeast genetic analyses indicating CD22 to be a T cell ligand for the SHP-1 SH2 domains. Based on these observations we have confirmed that CD22 is indeed expressed on mouse primary T cells and capable of associating with SHP-1. Significantly, CD22-deficient T cells demonstrate enhanced proliferation in response to anti-CD3 or allogeneic stimulation. Furthermore, the co-engagement of CD3 and CD22 results in a raising of TCR signaling thresholds hence demonstrating a previously unsuspected functional role for CD22 in primary T cells. |
