The human interleukin-6 (IL-6) receptor exists as a preformed dimer in the plasma membrane.
The recently solved X-ray structure of the extracellular portion of the interleukin-6 (IL-6) receptor (IL-6R) revealed an IL-6R dimer in the crystal lattice which probably represents a physiological dimer. Performing coprecipitation experiments with two differently tagged IL-6R variants expressed in COS-7 cells, we show that an IL-6R dimer exists in the plasma membrane in the absence of IL-6. Ligand binding does not seem to affect the dimerization status. When lysates of COS-7 cells expressing only one of the IL-6R variants are mixed, spontaneous dimerization occurs. Thus, the IL-6R dimer observed in the crystal structure represents a physiologically occurring phenomenon.
Schuster
Björn
B
Biochemisches Institut, Christian Albrechts Universität zu Kiel, Olshausenstr 40, D-24098 Kiel, Germany.
Meinert
Werner
W
Rose-John
Stefan
S
Kallen
Karl-Josef
KJ
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D019556:COS Cells; D002462:Cell Membrane / Q000378:metabolism; D019281:Dimerization; D006801:Humans; D011233:Precipitin Tests; D019947:Receptors, Interleukin-6 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D019947:Receptors, Interleukin-6