FGF5

Fibroblast growth factor 5 is a protein that in humans is encoded by the FGF5 gene.

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 gene was identified as an oncogene, which confers transforming potential when transfected into mammalian cells. Targeted disruption of the homolog of this gene in mouse resulted in the phenotype of abnormally long hair, which suggested a function as an inhibitor of hair elongation. Alternatively spliced transcript variants encoding different isoforms have been identified.
The disruption of FGF5 expression in mammals increases the length of the anagen (growth) phase of the hair cycle, resulting in a phenotype of extremely long hair. This has been shown in many species, including cats, dogs, mice, rabbits, sheep and goats (the so-called angora mutation) and even elephants and mammoths. FGF5 also affects the hair cycle in humans; blocking FGF5 in the human scalp (by applying a herbal extract that blocked FGF5) extends the hair cycle, resulting in less hair fall and increased hair growth.