A novel fibroblast growth factor receptor-5 preferentially expressed in the pancreas(1)

Using the polymerase chain reaction on human embryonic cDNAs, we isolated a cDNA encoding a novel 504 amino acid protein, termed fibroblast growth factor receptor (FGFR)-5, which is highly homologous to known FGFRs. The NH(2)-terminal portion of FGFR5 contains a putative secretory signal sequence, three typical immunoglobulin-like domains, six cysteines, and an acidic box, but no HAV motif. The COOH-terminal portion of FGFR5 contains one transmembrane domain but no intracellular kinase domain. Recombinant FGFR5 expressed in COS-7 cells is not secreted, but recombinant truncated FGFR5 lacking the predicted transmembrane domain is secreted. Acidic fibroblast growth factor (aFGF) and basic fibroblast growth factor (bFGF) do not bind to FGFR5. Among 23 adult human tissues, FGFR5 mRNA is preferentially expressed in the pancreas. These results suggest that FGFR5 may provide a binding site for some other fibroblast growth factors and may regulate some pancreatic function.