Identification of ezrin as an 81-kDa tyrosine-phosphorylated protein in T cells
| Autor: | Egerton, M., Burgess, W. H., Chen, D., Brian Druker, Bretscher, A., Samelson, L. E. |
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| Rok vydání: | 1992 |
| Předmět: | |
| Zdroj: | Scopus-Elsevier |
| ISSN: | 1550-6606 0022-1767 |
| Popis: | We have used APT affinity purification to isolate tyrosine-phosphorylated proteins from MRL lpr/lpr (lpr) mouse T cells. One such protein is pp81 ezrin, previously identified as a tyrosine-phosphorylated protein in epidermal growth factor-stimulated A431 carcinoma cells. Biochemical analyses in A431 and gastric parietal cells have revealed ezrin to be a cytoskeleton-associated cytosolic protein. In Jurkat T cells, however, using similar methods we have shown ezrin to be a cytosolic protein with no measurable cytoskeletal association. We also observed no increases in ezrin tyrosine phosphorylation in TCR-stimulated Jurkat T cells, unless the cells were pretreated with protein tyrosine phosphatase inhibitors, suggesting that T cell ezrin tyrosine phosphorylation is tightly controlled by protein tyrosine phosphatases. The fraction of tyrosine phosphorylated ezrin in lpr T cells was 5 to 10 times that observed in Jurkat T cells, which along with constitutive TCR-zeta phosphorylation and pp60fyn overexpression, is a feature of the lpr defect. |
| Databáze: | OpenAIRE |
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