Fos

Fos Background

Proto-oncogene c-Fos is a protein in humans that is encoded by FOS gene ^[1]. As a nuclear phosphoprotein, c-Fo forms heterodimer with c-jun (part of Jun family of transcription factors), resulting in the formation of AP-1 (Activator Protein-1) complex, which binds DNA at AP-1 specific sites at the promoter and enhancer regions of target genes and converts extracellular signals into changes of gene expression ^[2]. It plays an important role in many cellular functions and has been found to be overexpressed in a variety of cancers ^[3]. In the heterodimer, FOS and JUN/AP-1 basic regions each seems to interact with symmetrical DNA half-sites. On TGF-beta activation, c-Fo forms a multimeric SMAD3/SMAD4/JUN/FOS complex at the AP1/SMAD-binding site to regulate TGF-beta-mediated signaling. c-Fos has a critical function in regulating the development of cells destined to form and maintain the skeleton. It is thought to have an important role in signal transduction, cell proliferation, and differentiation. In growing cells, c-Fos activates phospholipid synthesis, possibly by activating CDS1 and PI4K2A.

[1] Curran T. The c-fos proto-oncogene. In: Reddy EP, Skalka AM, Curran T (eds.). The Oncogene Handbook 1988 Elsevier, New York, pp 307–327.
[2] Chiu R, Boyle WJ, et al. The c-Fos protein interacts with c-Jun/AP-1 to stimulate transcription of AP-1 responsive genes [J]. Cell. 1998, 54 (4): 541–52.
[3] Milde-Langosch K. The Fos family of transcription factors and their role in tumourigenesis [J]. Eur. J. Cancer. 2005, 41 (16): 2449–61.