Association of protein-tyrosine kinase with phospholipase C-gamma 1 in bone marrow-derived mouse mast cells.
Bone marrow-derived mouse mast cells contain phospholipase C-gamma 1 (PLC-gamma 1), 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-gamma 1 antibodies contained protein-tyrosine kinase (PTK), which phosphorylated PLC-gamma 1 in vitro. The tyrosine kinase activity coprecipitated with PLC-gamma 1-anti-PLC-gamma 1 complexes markedly increased when the cell lysates were obtained immediately after antigen challenge. The results indicate that PTK is associated with PLC-gamma 1 in the mast cells and that the kinase is activated upon cross-linking of Fc epsilon RI. Neither beta nor gamma subunit of Fc epsilon RI nor src family PTK was coprecipitated with the PLC-gamma 1-anti-PLC-gamma 1 complexes. In situ denaturation/renaturation experiments, which detect autophosphorylated kinases, indicated that the PTK associated with PLC-gamma 1 was a 44-kDa protein.
Fukamachi
H
H
Division of Immunobiology, La Jolla Institute for Allergy and Immunology, CA 92037.
Kawakami
Y
Y
Takei
M
M
Ishizaka
T
T
Ishizaka
K
K
Kawakami
T
T
D000818:Animals; D001854:Bone Marrow Cells; D004789:Enzyme Activation; D007700:Kinetics; D046911:Macromolecular Substances; D008407:Mast Cells / Q000201:enzymology*; D051379:Mice; D008808:Mice, Inbred CBA; D008970:Molecular Weight; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction; D010738:Type C Phospholipases / Q000378:metabolism*; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D046911:Macromolecular Substances; D019000:Phosphotyrosine; D014443:Tyrosine; D011505:Protein-Tyrosine Kinases; D010738:Type C Phospholipases