Activation of a tyrosine protein kinase is an early event in the stimulation of T lymphocytes by interleukin-2.
The ability of the T lymphocyte growth factor interleukin 2 (IL-2) to activate a tyrosine protein kinase in vivo was assessed by using antibodies to phosphotyrosine in conjunction with immunoblots. Treatment of the murine IL-2-dependent cytotoxic T cell line CTLL-2 with IL-2 resulted in an increase in tyrosine phosphorylation of several proteins of molecular weights ranging from 38,000 to 120,000. The tyrosine phosphorylation in the various proteins increased in a concomitant fashion and reached a maximum level within 15 min. The concentration of IL-2 required for inducing this phosphorylation was similar to that required for stimulating [3H]thymidine uptake, indicating that the increase in tyrosine phosphorylation correlated with the ability of IL-2 to stimulate the proliferation of the CTLL-2 cells. IL-2 was also found to induce the phosphorylation of proteins on tyrosine residues in short term cultures of human T lymphocytes. These results suggest that IL-2, like other polypeptide growth factors, acts by stimulating the activity of a tyrosine protein kinase.
Saltzman
E M
EM
Department of Pharmacology and Cancer Center, University of Rochester Medical Center, New York 14642.
Thom
R R
RR
Casnellie
J E
JE
D002460:Cell Line; D002478:Cells, Cultured; D004789:Enzyme Activation; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology*; D007700:Kinetics; D008213:Lymphocyte Activation; D010766:Phosphorylation; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D013601:T-Lymphocytes / Q000187:drug effects / Q000201:enzymology* / Q000276:immunology
D007376:Interleukin-2; D011505:Protein-Tyrosine Kinases