Functional characterization of the insulin-like growth factor I receptor on Jurkat T cells.
Insulin-like growth factor I (IGF-I) has been shown to be important in the maintenance, development, and proliferation of various types of leukocytes, particularly T cells. Radio-receptor binding assays demonstrate that Jurkat T cells bind 125I-IGF-I with an affinity of 1.77 nM (Kd) and express approximately 230 receptors/cell. Specificity studies show insulin also binds the IGF-I receptor with an affinity 20-fold lower than that of IGF-I. Interaction of IGF-I with its receptor on Jurkat T cells induces the phosphorylation of tyrosine kinase which is detectable by Western blotting. The 95,000 MW protein detected is equivalent to the molecular weight of the beta chain of the IGF-I receptor described in other types of cells. These studies characterize the binding of IGF-I to its receptor on Jurkat T cells, demonstrate that IGF-I binding induces tyrosine phosphorylation, and support the hypothesis that IGF-I is important in the induction of T cell activation.
Cross
R J
RJ
Department of Microbiology-Immunology, University of Kentucky Medical Center, Lexington 40536-0084, USA.
Elliott
L H
LH
Morford
L A
LA
Roszman
T L
TL
McGillis
J P
JP
D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008213:Lymphocyte Activation; D016399:Lymphoma, T-Cell / Q000473:pathology*; D009363:Neoplasm Proteins / Q000378:metabolism; D010766:Phosphorylation; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D011869:Radioligand Assay; D017526:Receptor, IGF Type 1 / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D007328:Insulin; D009363:Neoplasm Proteins; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1; D015740:Calcitonin Gene-Related Peptide