A serine phosphatase is involved in CD2-mediated activation of human T lymphocytes and natural killer cells
| Autor: | Y Samstag, A Bader, S C Meuer |
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| Rok vydání: | 1991 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 147:788-794 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.147.3.788 |
| Popis: | We investigated early activation events after T cell triggering via the Ag receptor (TCR/CD3) complex as compared to activation via the CD2 surface molecule. To this end, resting peripheral human T lymphocytes were preincubated with 32P-orthophosphate and subsequently exposed to mitogenic mAb directed at either TCR/CD3 or CD2 for varying time periods. Cells were lysed and postnuclear lysates subjected to two-dimensional-gel electrophoresis (IEF and SDS-PAGE). As early as 10 min after stimulation through CD2, dephosphorylation of a cytosolic 19-kDa protein was observed. In contrast, this protein remained phosphorylated in unstimulated as well as CD3 activated T cells. Phosphoprotein (pp) 19 dephosphorylation was transient because, at later time points (2-4 h) after CD2 triggering, this protein was phosphorylated again. Phosphoaminoacid analysis indicated that pp19 is dephosphorylated on serine residues. Identical results were obtained using a CD2+ but TCR/CD3- human NK cell clone indicating that pp19 dephosphorylation occurs independent of surface expression of a TCR/CD3 complex. These data show that, in addition to protein phosphorylation events, serine dephosphorylation is involved in T cell triggering. More important, a selective signaling mechanism appears to be linked to T cell activation through the CD2 pathway. |
| Databáze: | OpenAIRE |
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