Receptor tyrosine phosphatase, CD45 binds galectin-1 but does not mediate its apoptotic signal in T cell lines.
Galectin-1 (Gal-1) is an endogenous mammalian S-type lectin with highly pleiotropic effect on different tissues. The viability of the lymphoid cells is reduced by gal-1 by triggering apoptosis, however, the mechanism of the gal-1 induced apoptosis is still under investigation. The receptor tyrosine phosphatase, CD45, a heavily glycosylated cell surface molecule binds to gal-1 with high affinity, however, its contribution to the gal-1 induced apoptosis is still controversial. In this study we show that galectin-1 binds to cells deficient for CD45, although CD45 is one of the galectin-1-binding cell surface proteins on T cells. Moreover, the CD45 deficient Jurkat variant, J45.01 responds readily with tyrosine phosphorylation and subsequent apoptosis to galectin-1 treatment in a similar degree as its wild type counterpart, Jurkat does. These results strongly indicate that CD45 is not the receptor via gal-1 mediates the apoptotic signal into the cells as it was suggested in previous studies.
Fajka-Boja
Roberta
R
Lymphocyte Signal Transduction Laboratory, Institute of Genetics, Biological Research Center of Hungarian Academy of Sciences, Szeged, Hungary.
Szemes
Marianna
M
Ion
Gabriela
G
Légrádi
Adám
A
Caron
Michel
M
Monostori
Eva
E
D017209:Apoptosis; D004705:Endocytosis; D037483:Galectin 1; D037161:Galectins; D006388:Hemagglutinins / Q000378:metabolism*; D006801:Humans; D019169:Jurkat Cells; D017493:Leukocyte Common Antigens / Q000378:metabolism* / Q000502:physiology; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000166:cytology / Q000201:enzymology* / Q000276:immunology*; D014407:Tumor Cells, Cultured
D037483:Galectin 1; D037161:Galectins; D006388:Hemagglutinins; D019000:Phosphotyrosine; D017493:Leukocyte Common Antigens