Src-like adaptor protein regulates TCR expression on thymocytes by linking the ubiquitin ligase c-Cbl to the TCR complex.
The adaptor molecule SLAP and E3 ubiquitin ligase c-Cbl each regulate expression of T cell receptor (TCR)-CD3 on thymocytes. Here we provide genetic and biochemical evidence that both molecules function in the same pathway. TCR-CD3 expression was similar in the absence of SLAP and/or c-Cbl. SLAP and c-Cbl were found to interact, and their expression together downregulated CD3epsilon. This required multiple domains in SLAP and the ring finger of c-Cbl. Furthermore, expression of SLAP and c-Cbl together induced TCRzeta ubiquitination and degradation, preventing the accumulation of fully assembled recycling TCR complexes. These studies indicate that SLAP links the E3 ligase activity of c-Cbl to the TCR, allowing for stage-specific regulation of TCR expression.
Pubmed ID: 16327786 RIS Download
Animals | Antigens, CD3 | Flow Cytometry | Humans | Immunoblotting | Jurkat Cells | Mice | Mice, Mutant Strains | Proto-Oncogene Proteins c-cbl | Proto-Oncogene Proteins pp60(c-src) | Receptors, Antigen, T-Cell | T-Lymphocytes | Transfection