Acts as a ligand for FGFR1, FGFR2, FGFR3 and FGFR4 (By similarity). Also acts as an integrin ligand which is required for FGF2 signaling (By similarity). Plays an important role in the regulation of cell survival, cell division, cell differentiation and cell migration (By similarity). Functions as a potent mitogen in vitro. Can induce angiogenesis (By similarity). Exported from cells by an endoplasmic reticulum (ER)/Golgi-independent mechanism. Unconventional secretion of FGF2 occurs by direct translocation across the plasma membrane (By similarity). Binding of exogenous FGF2 to FGFR facilitates endocytosis followed by translocation of FGF2 across endosomal membrane into the cytosol (By similarity). Nuclear import from the cytosol requires the classical nuclear import machinery (By similarity). Belongs to the heparin-binding growth factors family.