Receptor recognition sites of cytokines are organized as exchangeable modules. Transfer of the leukemia inhibitory factor receptor-binding site from ciliary neurotrophic factor to interleukin-6.
Interleukin-6 (IL-6) and ciliary neurotrophic factor (CNTF) are "4-helical bundle" cytokines of the IL-6 type family of neuropoietic and hematopoietic cytokines. IL-6 signals by induction of a gp130 homodimer (e.g. IL-6), whereas CNTF and leukemia inhibitory factor (LIF) signal via a heterodimer of gp130 and LIF receptor (LIFR). Despite binding to the same receptor component (gp130) and a similar protein structure, IL-6 and CNTF share only 6% sequence identity. Using molecular modeling we defined a putative LIFR binding epitope on CNTF that consists of three distinct regions (C-terminal A-helix/N-terminal AB loop, BC loop, C-terminal CD-loop/N-terminal D-helix). A corresponding gp130-binding site on IL-6 was exchanged with this epitope. The resulting IL-6/CNTF chimera lost the capacity to signal via gp130 on cells without LIFR, but acquired the ability to signal via the gp130/LIFR heterodimer and STAT3 on responsive cells. Besides identifying a specific LIFR binding epitope on CNTF, our results suggest that receptor recognition sites of cytokines are organized as modules that are exchangeable even between cytokines with limited sequence homology.
Kallen
K J
KJ
I. Medizinische Klinik, Abteilung Pathophysiologie, Johannes Gutenberg Universität Mainz, Obere Zahlbacher Str. 63, 55101 Mainz, Germany.
Grötzinger
J
J
Lelièvre
E
E
Vollmer
P
P
Aasland
D
D
Renné
C
C
Müllberg
J
J
Myer zum Büschenfelde
K H
KH
Gascan
H
H
Rose-John
S
S
D000818:Animals; D001665:Binding Sites; D019556:COS Cells; D020934:Ciliary Neurotrophic Factor; D000939:Epitopes / Q000737:chemistry / Q000378:metabolism; D006131:Growth Inhibitors; D006801:Humans; D015850:Interleukin-6 / Q000737:chemistry / Q000378:metabolism*; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines / Q000378:metabolism*; D008958:Models, Molecular; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D011487:Protein Conformation; D018121:Receptors, Cytokine / Q000378:metabolism*; D053606:Receptors, OSM-LIF; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D014407:Tumor Cells, Cultured
D020934:Ciliary Neurotrophic Factor; D000939:Epitopes; D006131:Growth Inhibitors; D015850:Interleukin-6; C507837:LIF protein, human; C507840:LIFR protein, human; D053605:Leukemia Inhibitory Factor; D053680:Leukemia Inhibitory Factor Receptor alpha Subunit; D008222:Lymphokines; D009419:Nerve Tissue Proteins; D018121:Receptors, Cytokine; D053606:Receptors, OSM-LIF; D011993:Recombinant Fusion Proteins