COMPARISON OF THE STRUCTURE OF THE MURINE INTERLEUKIN 2 (IL 2) RECEPTOR ON CYTOTOXIC AND HELPER T CELL LINES BY CHEMICAL CROSS‐LINKING OF 125I‐LABELED IL 2
- 1 October 1988
- journal article
- research article
- Published by Wiley in European Journal of Immunology
- Vol. 18 (10), 1515-1519
- https://doi.org/10.1002/eji.1830181007
Abstract
The structure of the murine interleukin 2 receptor (IL2R), on a cytotoxic (CTLL) and a helper (HT2) cell line, has been studied by a combination of chemical cross‐linking with 125I‐labeled IL2 and immunoprecipitation with an anti‐receptor monoclonal antibody (7D4). In CTLL cells both methods detected the major 57‐kDa IL2‐binding protein and in addition the cross‐linking studies revealed the presence of a 70–75‐kDa protein associated with the high‐affinity receptor. In the HT2 cell line, however, immunoprecipitation studies revealed three additional proteins of 18, 22 and 37 kDa to the expected 50‐kDa receptor protein. Again cross‐linking studies demonstrated the presence of a 70–75‐kDa protein, which was not immunoprecipitable with the 7D4 antibody. The low molecular polypeptides in HT2 cell were associated with the low‐affinity receptor and represented most likely breakdown products of the 50‐kDa protein. Whereas the 18‐ and 22‐kDa proteins were involved in ligand binding, the 37‐kDa fragment carried the epitope recognized by the 7D4 antibody. Comparative studies with two IL2R antibodies, PC61 and 7D4, revealed that only PC61 inhibited the formation of the IL2 α/β chain complex, although both antibodies reportedly prevent the biological response to IL2. It is speculated that the 37‐kDa fragment, which reacts with the 7D4 antibody, might be involved in IL2 signal transduction. Finally there was no evidence for the existence of a high molecular weight component of the IL2R, previously described as γ chain. In summary, the two‐chain structure of the IL2R has been confirmed for both murine cell lines with some heterogeneity of the α chain. The possibility was raised that a 37‐kDa fragment of the α chain plays a role of in signal transduction.This publication has 29 references indexed in Scilit:
- Contrasting interleukin 2 binding properties of the alpha (p55) and beta (p70) protein subunits of the human high-affinity interleukin 2 receptor.The Journal of Experimental Medicine, 1987
- Internalization of interleukin 2 is mediated by the beta chain of the high-affinity interleukin 2 receptor.The Journal of Experimental Medicine, 1987
- Interleukin 2 high-affinity receptor expression requires two distinct binding proteins.The Journal of Experimental Medicine, 1987
- Novel Interleukin-2 Receptor Subunit Detected by Cross-Linking Under High-Affinity ConditionsScience, 1986
- High-affinity receptor-mediated internalization and degradation of interleukin 2 in human T cells.The Journal of Experimental Medicine, 1986
- Molecular cloning and expression of cDNAs for the human interleukin-2 receptorNature, 1984
- Molecular cloning of cDNA encoding human interleukin-2 receptorNature, 1984
- T cell growth factor receptors. Quantitation, specificity, and biological relevanceThe Journal of Experimental Medicine, 1981
- Externally disposed plasma membrane proteins. I. Enzymatic iodination of mouse L cells.The Journal of cell biology, 1975
- Cleavage of Structural Proteins during the Assembly of the Head of Bacteriophage T4Nature, 1970