| Autor: |
Hidemi Uchiyama, Mikako Shirouzu, Shaun K. Olsen, Osami Kanagawa, Shigeyuki Yokoyama, Kazutaka Murayama, Mutsuko Kukimoto-Niino, Takaho Terada, Mitsutoshi Toyama, Naruhisa Ota, S. Kishishita |
| Rok vydání: |
2007 |
| Předmět: |
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| Zdroj: |
Journal of Biological Chemistry. 282:37191-37204 |
| ISSN: |
0021-9258 |
| DOI: |
10.1074/jbc.m706150200 |
| Popis: |
Interleukin (IL)-15 is a pleiotropic cytokine that plays a pivotal role in both innate and adaptive immunity. IL-15 is unique among cytokines due to its participation in a trans signaling mechanism in which IL-15 receptorα (IL-15Rα) from one subset of cells presents IL-15 to neighboring IL-2Rβ/γc-expressing cells. Here we present the crystal structure of IL-15 in complex with the sushi domain of IL-15Rα. The structure reveals that theα receptor-binding epitope of IL-15 adopts a unique conformation, which, together with amino acid substitutions, permits specific interactions with IL-15Rα that account for the exceptionally high affinity of the IL-15·IL-15Rα complex. Interestingly, analysis of the topology of IL-15 and IL-15Rα at the IL-15·IL-15Rα interface suggests that IL-15 should be capable of participating in a cis signaling mechanism similar to that of the related cytokine IL-2. Indeed, we present biochemical data demonstrating that IL-15 is capable of efficiently signaling in cis through IL-15Rα and IL-2Rβ/γc expressed on the surface of a single cell. Based on our data we propose that cis presentation of IL-15 may be important in certain biological contexts and that flexibility of IL-15Rα permits IL-15 and its three receptor components to be assembled identically at the ligand-receptor interface whether IL-15 is presented in cis or trans. Finally, we have gained insights into IL-15·IL-15Rα·IL-2Rβ·γc quaternary complex assembly through the use of molecular modeling. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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