Characterization of the recombinant extracellular domains of human interleukin-20 receptors and their complexes with interleukin-19 and interleukin-20.
The soluble extracellular domains of human interleukin-20 (IL-20) receptors I and II (sIL-20R1 and sIL20R2), along with their ligands IL-19 and IL-20, were expressed in Drosophila S2 cells and purified to homogeneity. Formation of the receptor/receptor and ligand/receptor complexes was studied by size exclusion chromatography. Both ligands and soluble receptors were found to be monomeric in solution; homo- or heterodimers are not formed even at elevated concentrations. Under native conditions, both IL-19 and IL-20 form stable ternary 1:1:1 complexes with the sIL-20R1 and sIL20R2 receptors, as well as high-affinity binary complexes with sIL-20R2. Unexpectedly, sIL-20R1 does not bind on its own to either IL-19 or IL-20. Thus, one of the possible consecutive mechanisms of formation of the signaling ternary complex may involve two steps: first, the ligand binds to receptor II, creating a high-affinity binding site for the receptor I, and only then does receptor I complete the complex.
Macromolecular Crystallography Laboratory, Center for Cancer Research, National Cancer Institute at Frederick, Maryland 21702-1201, USA.
Sergei
S
Pletnev
Eugenia
E
Magracheva
Serguei
S
Kozlov
Gregory
G
Tobin
Sergei V
SV
Kotenko
Alexander
A
Wlodawer
Alexander
A
Zdanov
D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D006031:Glycosylation; D006801:Humans; D016753:Interleukin-10 / Q000302:isolation & purification / Q000378:metabolism*; D007378:Interleukins / Q000302:isolation & purification / Q000378:metabolism*; D018123:Receptors, Interleukin / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
C421250:IL19 protein, human; D007378:Interleukins; D018123:Receptors, Interleukin; D011994:Recombinant Proteins; D016753:Interleukin-10; C422042:interleukin 20