Recombinant c-Fos protein

Recombinant c-Fos was expressed from full length (accession number NM 003131) with an amino terminal polyhistidine tag in a baculovirus system and purified by an affinity column in combination with FPLC chromatography. The purified recombinant protein is greater than 90% homogeneous and contains no detectable protease, DNase and RNase activity. c-Fos is one of the proteins that form the heteromeric AP-1 transcription factor complex. AP-1 proteins play a role in the expression of many genes involved in the regulation of cellular processes such as differentiation, proliferation and apoptosis. The transcription factor AP-1 is composed of a mixture of heterodimeric protein complexes derived from the Fos and Jun families, including c-Fos, FosB, Fra-1, c-Jun, JunB and JunD. c-Fos is a nuclear phosphoprotein that forms a tight but non-covalently linked complex with the Jun/AP-1 transcription factor. In the heterodimer, Fos and Jun/AP-1 basic regions each seem to interact with symmetrical DNA half sites. Upon TGF-b activation, c-Fos forms a multimeric SMAD3/SMAD4/Jun/Fos complex at the AP-1/SMAD-binding site to regulate TGF-b-mediated signaling. c-Fos has a critical function in regulating bone morphogenesis.