Induction of cell death via Fas (CD95, Apo-1) may be associated with but is not dependent on Fas-induced tyrosine phosphorylation.
Cross-linking of the Fas-antigen (CD95, Apo-1) triggers apoptosis in activated T cells and transformed T cell lines. Fas-induced apoptosis has been previously reported to require Fas-triggered tyrosine phosphorylation of various proteins. In the present study, we have compared the protein tyrosine phosphorylation pattern and the apoptosis sensitivity in a set of Jurkat variants selected for the absence or presence of T cell receptor (TCR)/CD3 expression and resistance or sensitivity to Fas-mediated apoptosis. While tyrosine phosphorylation upon Fas-ligation was readily apparent in wild-type Jurkat cells (which are sensitive to anti-Fas-induced apoptosis), drastically reduced tyrosine phosphorylation was observed in Fas-resistant Jurkat subclones (which still express CD95 on their surface). More importantly, TCR/CD3-negative Jurkat variants which expressed normal levels of CD95 and were fully susceptible to Fas-triggered cell death, did not show any protein tyrosine phosphorylation upon Fas-ligation. Taken together, our data demonstrate that Fas-induced cell death can be associated with but is not dependent on protein tyrosine phosphorylation.
Janssen
O
O
Department of Immunology, Paul-Ehrlich-Institute, Langen, Germany.
Lengl-Janssen
B
B
Oberg
H H
HH
Robertson
M J
MJ
Kabelitz
D
D
D000911:Antibodies, Monoclonal / Q000378:metabolism; D017209:Apoptosis / Q000276:immunology*; D006801:Humans; D007938:Leukemia / Q000378:metabolism; D010766:Phosphorylation; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014443:Tyrosine / Q000378:metabolism*; D019014:fas Receptor / Q000502:physiology*
D000911:Antibodies, Monoclonal; D017260:Receptor-CD3 Complex, Antigen, T-Cell; D019014:fas Receptor; D014443:Tyrosine