CHARACTERIZATION OF A PATHWAY FOR CILIARY NEUROTROPHIC FACTOR SIGNALING TO THE NUCLEUS

Components of a signaling pathway that couples the ciliary neurotrophi c factor (CNTF) receptor to induction of transcription were identified . CNTF stimulated the tyrosine phosphorylation of p91, a protein impli cated in interferon signaling pathways, and of two proteins that are d istinct but related to p91. Tyrosine-phosphorylated p91 translocated t o the nucleus, where p91 and p91-related proteins bound to a DNA seque nce found in promoters of genes responsive to CNTF. This DNA sequence, when inserted upstream of a reporter gene, conferred a transcriptiona l response to CNTF. A pathway that transduces interferon signals may t herefore have a more general function in the propagation of responses to certain neurotrophic factors.