Heparin-binding growth factor 1 is a protein that in humans is encoded by the FGF1 gene. The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF acidic is a potent growth factor for fibroblasts and endothelial cells. FGF acidic is involved in wound repair, angiogenesis, and development. FGF acidic is secreted from cells via an endoplasmic reticulum/Golgi independent mechanism. The ability of FGF acidic to bind to heparin sulfate is required for its ability to interact with FGF receptors and induce signaling. There are four distinct FGF receptors and each has multiple splice variants. FGF acidic binds with high affinity to many, but not all, FGFRs. Signaling cascades activated through FGF basic binding to FGFR include the ras-raf-MAPK, PLCγ/PKC, and PI3K/Akt pathways.