TY - JOUR
T1 - Crystal structure of the interleukin-15·interleukin-15 receptor α complex
T2 - Insights into trans and cis presentation
AU - Olsen, Shaun K.
AU - Ota, Naruhisa
AU - Kishishita, Seiichiro
AU - Kukimoto-Niino, Mutsuko
AU - Murayama, Kazutaka
AU - Uchiyama, Hidemi
AU - Toyama, Mitsutoshi
AU - Terada, Takaho
AU - Shirouzu, Mikako
AU - Kanagawa, Osami
AU - Yokoyama, Shigeyuki
PY - 2007/12/21
Y1 - 2007/12/21
N2 - 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 receptor α (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 the α 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.
AB - 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 receptor α (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 the α 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.
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U2 - 10.1074/jbc.M706150200
DO - 10.1074/jbc.M706150200
M3 - Article
C2 - 17947230
AN - SCOPUS:37549007225
SN - 0021-9258
VL - 282
SP - 37191
EP - 37204
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 51
ER -