Abstract
Bone marrow-derived mouse mast cells contain phospholipase C-γ1 (PLC-γ1), which is phosphorylated at tyrosine residues upon cross-linking of cell-bound IgE antibodies with multivalent antigen. It was found that immune complexes formed from digitonin lysates of the mast cells by monoclonal anti-PLC-γ1 antibodies contained protein-tyrosine kinase (PTK), which phosphorylated PLC-γ1 in vitro. The tyrosine kinase activity coprecipitated with PLC-γ1-anti-PLC-γ1 complexes markedly increased when the cell lysates were obtained immediately after antigen challenge. The results indicate that PTK is associated with PLC-γ1 in the mast cells and that the kinase is activated upon cross-linking of FcεRI. Neither β nor γ subunit of FcεRI nor src family PTK was coprecipitated with the PLC-γ1-anti-PLC-γ1 complexes. In situ denaturation/renaturation experiments, which detect autophosphorylated kinases, indicated that the PTK associated with PLC-γ1 was a 44-kDa protein.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9524-9528 |
| Number of pages | 5 |
| Journal | Proceedings of the National Academy of Sciences of the United States of America |
| Volume | 89 |
| Issue number | 20 |
| DOIs | |
| State | Published - Oct 15 1992 |
| Externally published | Yes |
Keywords
- FcRI
- Signal transduction
ASJC Scopus subject areas
- General