They are involved in a wide variety of processes, most notably as crucial elements for normal development in animal cells.
These growth factors typically act as a systemic or locally circulating molecules of extracellular origin that activate cell surface receptors.
This 'acid box' motif interacts with the heparan sulfate binding site to prevent receptor activation in the absence of FGFs.
A mitogenic growth factor activity was found in pituitary extracts by Armelin in 1973[14] and further work by Gospodarowicz as reported in 1974 described a more defined isolation of proteins from cow brain extract which, when tested in a bioassay that caused fibroblasts to proliferate, led these investigators to apply the name "fibroblast growth factor.
[16][17] Promiscuous refers to the biochemistry and pharmacology concept of how a variety of molecules can bind to and elicit a response from single receptor.
FGF is critical during normal development of both vertebrates and invertebrates and any irregularities in their function leads to a range of developmental defects.
[19][20][21][22] FGFs secreted by hypoblasts during avian gastrulation play a role in stimulating a Wnt signaling pathway that is involved in the differential movement of Koller's sickle cells during formation of the primitive streak.
[25] LMW FGF2 is primarily cytoplasmic and functions in an autocrine manner, whereas HMW FGF2s are nuclear and exert activities through an intracrine mechanism.
FGF1 and FGF2 stimulate angiogenesis and the proliferation of fibroblasts that give rise to granulation tissue, which fills up a wound space/cavity early in the wound-healing process.
During the development of the central nervous system, FGFs play important roles in neural stem cell proliferation, neurogenesis, axon growth, and differentiation.
Members of the FGF19 subfamily (FGF15, FGF19, FGF21, and FGF23) bind less tightly to heparan sulfates, and so can act in an endocrine fashion on far-away tissues, such as intestine, liver, kidney, adipose, and bone.
[37] Some FGF ligands (particularly FGF2) have been demonstrated to enhance tissue repair (e.g. skin burns, grafts, and ulcers) in a range of clinical settings.