Pseudo-high affinity interleukin 2 (IL-2) receptor lacks the third component that is essential for functional IL-2 binding and signaling.

Content Provider	Scilit
Author	Arima, Nobuyoshi Kamio, M. Imada, Kazunori Hori, T. Hattori, T. Tsudo, M. Okuma, M. Uchiyama, T.
Copyright Year	1992
Description	Journal: The Journal of experimental medicine Functional studies of the interleukin 2 receptor (IL-2R) of two (ED515-D and Kit225) IL-2-dependent and three (ED515-I, 3T3-alpha beta 11, and Hut102) IL-2-independent cell lines were done. All of these cell lines appeared to express high as well as low affinity IL-2R. However, ED515-I and 3T3-alpha beta 11, which expressed the IL-2R beta chain, did not bind IL-2 at all when IL-2 binding to their IL-2R alpha chain was blocked with anti-Tac monoclonal antibody, whereas the intermediate affinity binding in ED515-D, Kit225, and Hut102 cells remained. We tentatively called the high affinity IL-2R of the former cells pseudo-high affinity IL-2R. The dissociation constant of pseudo-high affinity IL-2R was higher than that of ordinary high affinity IL-2R. Internalization of cell-bound 125I-IL-2 into ED515-I and 3T3-alpha beta 11 cells was less efficient than that into ED515-D cells. The addition of IL-2 neither promoted cell growth nor upregulated IL-2R alpha chain expression in ED515-I and 3T3-alpha beta 11 cells. Furthermore, tyrosine phosphorylation of the cellular proteins (p120, p98, p96, p54, and p38) was induced or enhanced in response to the addition of IL-2 in ED515-D and Kit225 cells, but not in the cell lines expressing pseudo-high affinity IL-2R. Finally, 125I-IL-2 crosslinking followed by SDS-PAGE analysis showed an 80-kD band corresponding to p65 + IL-2, in addition to bands corresponding to IL-2R alpha and beta chain + IL-2 in cells bearing ordinary high affinity IL-2R but not in cells with pseudo-high affinity IL-2R. Taken together, we consider that another protein whose molecular mass is approximately 65 kD is functionally important in IL-2 binding and subsequent signal transduction and may be the third component of IL-2R.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2119428/pdf http://jem.rupress.org/content/176/5/1265.full.pdf
ISSN	00221295
DOI	10.1084/jem.176.5.1265
Journal	The Journal of experimental medicine
Issue Number	5
Volume Number	176
Language	English
Publisher	Rockefeller University Press
Publisher Date	1992-11-01
Access Restriction	Open
Subject Keyword	Journal: The Journal of experimental medicine Biochemistry and Molecular Biology High Affinity Alpha Beta Beta Chain Affinity Il 2r
Content Type	Text
Resource Type	Article
Subject	Physiology