FRA1/FOSL1 Recombinant Rabbit mAb (S-3772-68)

FRA1 (Fos-related antigen 1, also known as FOSL1) is a core member of the Fos subfamily within the activator protein-1 (AP-1) transcription factor family, encoded by the FOSL1 gene on human chromosome 11. Its protein structure contains a highly conserved basic leucine zipper domain, through which it forms heterodimers with Jun proteins (such as c-Jun, JunB, JunD) to specifically recognize and bind to TPA-responsive elements or AP-1 binding sites on DNA, thereby regulating the transcription of downstream target genes. Under physiological conditions, FRA1 is expressed at low levels in various tissues but plays fine-tuned regulatory roles in processes such as cell proliferation, differentiation, migration, and apoptosis, particularly in bone metabolism where FRA1 maintains bone homeostasis by regulating the balance between osteoclast and osteoblast differentiation. However, aberrant high expression of FRA1 is extremely common in various malignancies, including breast cancer, lung cancer, colorectal cancer, and melanoma. As an oncogenic transcription factor, FRA1 drives tumor cell invasion, metastasis, and chemotherapy resistance by transcriptionally activating matrix metalloproteinases, cell cycle regulators, and epithelial-mesenchymal transition-related genes. Notably, the FRA1 protein has a very short half-life, and its stability is precisely regulated by post-translational modifications: serine phosphorylation (mediated by ERK, JNK, and RSK kinases) significantly prolongs its half-life and enhances its transcriptional activity, while the ubiquitin-proteasome pathway mediates its rapid degradation. Furthermore, the functions of FRA1 are not confined to nuclear transcriptional regulation; recent studies have revealed that it can also translocate to mitochondria, participating in the regulation of mitochondrial metabolism and reactive oxygen species production, thereby influencing metabolic reprogramming in tumor cells. In non-neoplastic diseases, FRA1 also plays important roles—for example, in pulmonary fibrosis, FRA1 promotes collagen deposition by inducing fibroblast activation; in rheumatoid arthritis, FRA1 synergizes with inflammatory cytokines to exacerbate joint destruction. In summary, FRA1, as a multifunctional transcription factor, plays a central hub role in normal physiological regulation, tumor progression, and various inflammatory diseases through dynamic cooperation with the AP-1 complex.