Fibroblast Growth Factor 9 (FGF9) Active Protein

The protein encoded by this gene is a member of the fibroblast growth factor (FGF) family. FGF family members possess broad mitogenic and cell survival activities, and are involved in a variety of biological processes, including embryonic development, cell growth, morphogenesis, tissue repair, tumor growth and invasion. This protein was isolated as a secreted factor that exhibits a growth-stimulating effect on cultured glial cells. In nervous system, this protein is produced mainly by neurons and may be important for glial cell development. Expression of the mouse homolog of this gene was found to be dependent on Sonic hedgehog (Shh) signaling. Mice lacking the homolog gene displayed a male-to-female sex reversal phenotype, which suggested a role in testicular embryogenesis. [provided by RefSeq]

Function: May have a role in glial cell growth and differentiation during development, gliosis during repair and regeneration of brain tissue after damage, differentiation and survival of neuronal cells, and growth stimulation of glial tumors.

Subunit structure: Monomer.

Subcellular location: Secreted.

Tissue specificity: Glial cells.

Post-translational modification: Three molecular species were found (30 kDa, 29 kDa and 25 kDa), cleaved at Leu-4, Val-13 and Ser-34 respectively. The smaller ones might be products of proteolytic digestion. Furthermore, there may be a functional signal sequence in the 30 kDa species which is uncleavable in the secretion step.N-glycosylated.

Involvement in disease: Defects in FGF9 are the cause of multiple synostoses syndrome type 3 (SYNS3) [

MIM:612961]. Multiple synostoses syndrome is an autosomal dominant condition characterized by progressive joint fusions of the fingers, wrists, ankles and cervical spine, characteristic facies and progressive conductive deafness. Ref.9

Miscellaneous: Biochemical analysis of the Asn-99 mutation reveals a significantly impaired FGF signaling, as evidenced by diminished activity of the MAPK1/MAPK2 pathway and decreases CTNNB1 and MYC expression when compared with wild-type protein. Binding of mutant protein to the receptor FGFR3 is severely impaired, although homodimerization of mutant to itself or wild-type is not detectably affected, providing a basis for the observed defective FGF9 signaling.

Sequence similarities: Belongs to the heparin-binding growth factors family.