2psm

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spinqualitylabelsall models PDB ID 2psm Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image
, resolution 2.19Å
Ligands:
Gene:	Il15 (Mus musculus), Il15ra (Mus musculus)
Resources:	FirstGlance, OCA, PDBsum, RCSB
Coordinates:	save as pdb, mmCIF, xml

Crystal structure of Interleukin 15 in complex with Interleukin 15 receptor alpha

Overview

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 alpha (IL-15Ralpha) from one subset of cells presents IL-15 to neighboring IL-2Rbeta/gammac-expressing cells. Here we present the crystal structure of IL-15 in complex with the sushi domain of IL-15Ralpha. The structure reveals that the alpha receptor-binding epitope of IL-15 adopts a unique conformation, which, together with amino acid substitutions, permits specific interactions with IL-15Ralpha that account for the exceptionally high affinity of the IL-15.IL-15Ralpha complex. Interestingly, analysis of the topology of IL-15 and IL-15Ralpha at the IL-15.IL-15Ralpha 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-15Ralpha and IL-2Rbeta/gammac 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-15Ralpha 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-15Ralpha.IL-2Rbeta.gammac quaternary complex assembly through the use of molecular modeling.

About this Structure

2PSM is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.

Reference

Crystal Structure of the interleukin-15.interleukin-15 receptor alpha complex: insights into trans and cis presentation., Olsen SK, Ota N, Kishishita S, Kukimoto-Niino M, Murayama K, Uchiyama H, Toyama M, Terada T, Shirouzu M, Kanagawa O, Yokoyama S, J Biol Chem. 2007 Dec 21;282(51):37191-204. Epub 2007 Oct 18. PMID:17947230

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