Structural and functional studies on the human interleukin-6 receptor. Binding, cross-linking, internalization, and degradation of interleukin-6 by fibroblasts transfected with human interleukin-6-receptor cDNA.
A cDNA coding for the human interleukin-6 receptor (IL-6-R) has been expressed stably in murine NIH/3T3 fibroblasts. Transfected cells exhibited a single class of binding sites for 125I-labeled recombinant human interleukin-6 (125I-rhIL-6) (Kd = 440 pM, 20,000 receptors per cell). Affinity cross-linking of 125I-rhIL-6 to the IL-6-R-expressing NIH/3T3 cells led to the detection of three 125I-rhIL-6-containing protein complexes with molecular masses of 100, 120, and 200 kDa suggesting a complex organization of the IL-6-R in the plasma membrane. IL-6 added to the transfected NIH/3T3 cells exerted growth inhibition. This anti-growth effect was observed by the measurement of cell numbers and ornithine decarboxylase mRNA expression. IL-6-R overexpressing fibroblasts internalized 125I-rhIL-6. Intracellular limited proteolysis of IL-6 could be demonstrated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A possible implication of skin fibroblasts in the catabolism of IL-6 is discussed.
Rose-John
S
S
Institut für Biochemie, Rheinisch-Westfälisch Technische Hochschule Aachen, Federal Republic of Germany.
Hipp
E
E
Lenz
D
D
Legrés
L G
LG
Korr
H
H
Hirano
T
T
Kishimoto
T
T
Heinrich
P C
PC
D001345:Autoradiography; D003432:Cross-Linking Reagents; D004247:DNA / Q000235:genetics*; D004587:Electrophoresis, Agar Gel; D005340:Fibrinogen / Q000032:analysis; D005347:Fibroblasts / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000378:metabolism*; D009955:Ornithine Decarboxylase / Q000032:analysis; D010957:Plasmids; D011233:Precipitin Tests; D012333:RNA, Messenger / Q000032:analysis; D011971:Receptors, Immunologic / Q000235:genetics / Q000378:metabolism*; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins / Q000378:metabolism; D013329:Structure-Activity Relationship; D014162:Transfection
D003432:Cross-Linking Reagents; D015850:Interleukin-6; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D019947:Receptors, Interleukin-6; D011994:Recombinant Proteins; D005340:Fibrinogen; D004247:DNA; D009955:Ornithine Decarboxylase