The CRLF1 gene encodes a member of the cytokine type I receptor family. The CRLF1 protein heterodimerizes with cardiotrophin-like cytokine factor 1 (CLCF1) to bind ciliary neurotrophic factor receptors (CNFTR), in doing so it competes with ciliary neurotrophic factor (CNTF) for binding to CNTFR. This binding activates the JAK/STAT signaling pathway and promotes survival of signal-receiving neuronal cells.
The human CRLF1 protein consists of 422 amino acids. CRLF1 is a secreted protein that comprises one immunoglobulin (Ig)-like domain and two fibronectin type III (FNIII) domains. CRLF1 expression was detected in lymph nodes, spleen, thymus, appendix, placenta, stomach, and fetal lung.