Recombinant Canine KGF/FGF-7 Protein

The fibroblast growth factor (FGF) family consists of twenty three known structurally-related proteins that play key roles in development, morphogenesis, angiogenesis, wound healing and tumorigenesis (1). All FGFs share a common structural fold, the beta -trefoil scaffold, in a conserved central region of approximately 120 amino acid (aa), which contains the active site and a heparin binding site (2). FGF-7, also known as keratinocyte growth factor (KGF), was originally identified from the conditioned medium of a human embryonic lung fibroblast cell line (3). It is secreted by cells of mesenchymal origin and functions predominantly on epithelial cells (1). The mature caFGF-7 is generated from a 194 aa precursor protein by cleavage of the first 31 aa at the N-terminus. It shares 97.4% and 95.9% sequence identity with human and mouse KGF, respectively (4). FGFs signal through high affinity tyrosine kinase receptors (FGF R) (5). Cellular responses to FGFs are modulated by heparan sulfate proteoglycans that are also known as low affinity FGF receptors and by heparin (6). Various isoforms of the four FGF R exist (FGF R‑1 through -4). They are produced from alternatively spliced transcripts in both the extracellular and intracellular domains. FGF-7 signals through the FGF R2IIIb (also known as KGF R), which is a spliced variant of FGF R2 (7). KGF R binds FGF-1 and FGF-7 with high affinity and FGF-2 with a 20-fold lower affinity (8).