Characterization of a novel protein (FGFRL1) from human cartilage related to FGF receptors

Utilizing a subtractive cDNA cloning approach we have identified a novel pr otein from human cartilage. This protein represents an integral membrane pr otein with 504 amino acids and a molecular mass of 55 kDa. It is composed o f a signal peptide, three extracellular Ig-like modules, a transmembrane se gment, and a short intracellular domain. The extracellular domain is closel y related to the extracellular domain of FGF receptors. The intracellular d omain, however, does not show any similarity to the protein tyrosine kinase domain of FGF receptors. The novel gene (FGFRL1) is located on human chrom osome 4 band p16 in close proximity to the gene for FGFR3. Its mRNA is pref erentially expressed in cartilaginous tissues. Owing to the structural simi larity, it is conceivable that the novel protein plays a role in the modula tion of FGF receptor activity. (C) 2000 Academic Press.