Ciliary neurotrophic factor (CNTF) is a member of the gp130 family of cytokines. CNTF is a survival factor for various neuronal cell types and seems to prevent the degeneration of motor axons after axotomy suggesting it may be a potential therapeutic for treating neurodegeneration and nerve injury. CNTF acts on oligodendrocytes by favoring their final maturation, and this effect is mediated through the 130kDa glycoprotein receptor common to the CNTF family and transduced through the Janus kinase pathway. The functional receptor complex of CNTF is composed of the CNTF receptor alpha (CNTFR), gp130 and the leukemia inhibitory factor receptor (LIFR). The structure of CNTF is a four helical bundle []. CNTF acts as a homodimer. Three regions on CNTF have been identified as binding sites for its receptors. The ligand-receptor interactions are mediated through the cytokine binding domains (CBDs) and/or the immunoglobulin-like domains of the receptors. However, in the case of CNTF, the precise nature of the protein-protein contacts in the signalling complex has not yet been resolved, but there is evidence that the membrane distal CBD (CBD1) of LIFR associates in vitro with soluble CNTFR in the absence of CNTF [, ].
