J. Huber et al., CHARACTERIZATION OF HIGH-AFFINITY AND LOW-AFFINITY RECEPTORS FOR CILIARY NEUROTROPHIC FACTOR, European journal of biochemistry, 218(3), 1993, pp. 1031-1039
Ciliary neurotrophic factor (CNTF) supports the survival of a wide var
iety of neuronal cells in culture. To characterise the receptor(s) med
iating the biological responses of CNTF we measured the binding of rad
iolabelled CNTF to chick sympathetic neurons and human neuroblastoma c
ells. Two distinct CNTF-binding sites with high and low affinity for t
he ligand were identified by steady-state binding experiments. Further
more, two low-affinity binding sites could be discriminated on the bas
is of the dissociation rates. Cross-linking experiments showed that CN
TF interacts with two proteins, one of 80 kDa and one of 140 kDa. The
identity of the 80-kDa protein was determined by transient transfectio
n experiments with the rat CNTF-binding protein CNTFRalpha while the p
roperties of the 140-kDa protein correspond to those of gp130. Antisen
se experiments confirmed that CNTTRalpha is necessary for high affinit
y binding of I-125-CNTF and therefore a necessary subunit of the high-
affinity receptor.