Fos proto-oncogene, AP-1 transcription factor subunit (c-Fos) (c-Fos)

Fos proto-oncogene, AP‑1 transcription factor subunit (commonly known as c-Fos) is a nuclear protein encoded by the FOS gene. It is a member of the Fos family of transcription factors and functions primarily by forming heterodimers with proteins from the Jun family to create the Activator Protein 1 (AP‑1) complex. This complex binds specific DNA sequences at promoter/enhancer regions to regulate downstream gene expression in response to diverse extracellular signals such as growth factors, cytokines, neurotransmitters, UV radiation, and stress. c-Fos acts as an immediate early gene—its mRNA and protein are rapidly induced within minutes after stimulation—and plays key roles in cell proliferation, differentiation, survival/apoptosis pathways, neural plasticity including learning/memory formation, and oncogenic transformation. In neuroscience research it is widely used as a marker for neuronal activation due to its rapid induction following synaptic activity or external stimuli. Dysregulation or overexpression of c‑Fos has been implicated in cancer development/progression and neurodegenerative diseases such as Alzheimer’s disease through effects on chromatin accessibility and downstream target genes involved in memory processes.

Other names

FOSProto-oncogene c-FosAP-1 transcription factor subunit c-Fos