Table 1.
Specificity of ligands for FGF receptor isoforms
| FGF subfamily | FGF | FGFR specificity |
|---|---|---|
| FGF1 | FGF1 | All FGFRs |
| FGF2 | FGFR1c, FGFR3c > FGFR2c, FGFR1b, FGFR4 | |
| FGF4 | FGF4 | |
| FGF5 | FGFR1c, FGFR2c > FGFR3c, FGFR4 | |
| FGF6 | ||
| FGF7 | FGF3 | |
| FGF7 | FGFR2b > FGFR1b | |
| FGF10 | ||
| FGF22 | ||
| FGF8 | FGF8 | |
| FGF17 | FGFR3c > FGFR4 > FGFR2c > | |
| FGF18 | FGFR1c >> FGFR3b | |
| FGF9 | FGF9 | FGFR3c > FGFR2c > FGFR1c, FGFR3b >> FGFR4 |
| FGF16 | ||
| FGF20 | ||
| FGF19 | FGF19 | |
| FGF21 | FGFR1c, FGFR2c, FGFR3c, FGFR4 | |
| FGF23 | (weak activity) | |
| FGF11 | FGF11 | |
| FGF12 | ||
| FGF13 | No known activity | |
| FGF14 |
Notes: FGF receptors 1–3 are alternatively spliced, while FGF receptor 4 is not. This alternative splicing event is regulated in a tissue-specific manner and dramatically affects ligand binding. For example, epithelially expressed FGF receptor 2b can be activated by mesenchymal FGF7 and FGF10; however, these ligands show no activity towards mesenchymally expressed FGF receptor 2c.
Abbreviations: FGF, fibroblast growth factor; FGFR, fibroblast growth factor receptor.