FOS and rheumatoid arthritis: Since the RSK2 signaling pathway induces the transactivation activities of AP-1, and NF-κB regulates cell proliferation, cell migration, and inflammation19, 39 by regulation of activated T-cell 3 (NFAT3) nuclear factors and RSK2/NFAT3-mediated IL-2 promoter activity39, these results suggest that RSK2 plays a critical role in T-cell activation in vitro and in vivo40, and provide us with an opportunity to establish the hypothesis that RSK2 might be involved in RA development.