The Journal of Immunology, Vol 139, Issue 6 1918-1926, Copyright © 1987 by American Association of Immunologists

ARTICLES

The murine interleukin 2 receptor. Irreversible cross-linking of radiolabeled interleukin 2 to high affinity interleukin 2 receptors reveals a noncovalently associated subunit

H Saragovi and TR Malek

The murine interleukin 2 (IL-2) receptor is a 55- to 60-kDa glycoprotein (p58) that binds IL-2 at a high and low affinity. In this investigation, we have identified sublines of EL4 that vary in their capacity to express high affinity IL-2 receptors after transfection of the IL-2 receptor cDNA. These and other cell populations were used to determine whether unique membrane molecules were specifically associated with the high affinity IL-2 receptor. Irreversible chemical cross-linking of [125I]IL-2 to only high affinity IL-2 receptors resulted in detection of IL-2 cross-linked to p58 as a 70- to 75-kDa band and other complexes of 90 to 95 kDa, 115 kDa, 150 kDa, 170 to 190 kDa, and 245 kDa. Antibodies specific for p58 resulted in precipitation of each of these complexes. However, disruption of noncovalent interactions prior to immunoprecipitation resulted in an inability to detect the material at 90 to 95 kDa. Therefore, we conclude that this complex most likely represented IL-2 cross-linked to a 75- to 80-kDa subunit that was noncovalently associated with p58. The other complexes greater than 150 kDa may represent these subunits cross-linked to each other. The detection of all the cross-linked complexes larger than 75 kDa appeared to be directly related to formation of high affinity IL-2 receptors because IL-2 was cross-linked only to p58 for three cell lines that exclusively expressed low affinity IL-2 receptors. Thus, high affinity murine IL-2 receptors are comprised of at least one alpha (p58)- and beta (p75)-subunit. Our data also raise the possibility of a more complex subunit structure.

This article has been cited by other articles:

				F. Olosz and T. R. Malek Structural Basis for Binding Multiple Ligands by the Common Cytokine Receptor gamma -Chain J. Biol. Chem., March 29, 2002; 277(14): 12047 - 12052. [Abstract] [Full Text] [PDF]

				T. R. Malek, A. Yu, P. Scibelli, M. G. Lichtenheld, and E. K. Codias Broad Programming by IL-2 Receptor Signaling for Extended Growth to Multiple Cytokines and Functional Maturation of Antigen-Activated T Cells J. Immunol., February 1, 2001; 166(3): 1675 - 1683. [Abstract] [Full Text] [PDF]

				A. Yu, F. Olosz, C. Y. Choi, and T. R. Malek Efficient Internalization of IL-2 Depends on the Distal Portion of the Cytoplasmic Tail of the IL-2R Common {gamma}-Chain and a Lymphoid Cell Environment J. Immunol., September 1, 2000; 165(5): 2556 - 2562. [Abstract] [Full Text] [PDF]

				M. D. Marmor, M. F. Bachmann, P. S. Ohashi, T. R. Malek, and M. Julius Immobilization of glycosylphosphatidylinositol-anchored proteins inhibits T cell growth but not function Int. Immunol., September 1, 1999; 11(9): 1381 - 1393. [Abstract] [Full Text] [PDF]

				R. P. Junghans, A. L. Stone, and M. S. Lewis Biophysical Characterization of a Recombinant Soluble Interleukin 2 Receptor (Tac) J. Biol. Chem., May 3, 1996; 271(18): 10453 - 10460. [Abstract] [Full Text] [PDF]

				M. Tigges, L. Casey, and M. Koshland Mechanism of interleukin-2 signaling: mediation of different outcomes by a single receptor and transduction pathway Science, February 10, 1989; 243(4892): 781 - 786. [Abstract] [PDF]

				F. Olosz and T. R. Malek Three Loops of the Common gamma Chain Ectodomain Required for the Binding of Interleukin-2 and Interleukin-7 J. Biol. Chem., September 22, 2000; 275(39): 30100 - 30105. [Abstract] [Full Text] [PDF]

				A. Yu and T. R. Malek The Proteasome Regulates Receptor-mediated Endocytosis of Interleukin-2 J. Biol. Chem., January 5, 2001; 276(1): 381 - 385. [Abstract] [Full Text] [PDF]