NFATz: A novel Rel Similarity Domain containing protein

Nuclear Factor of Activated T cell (NFAT) is a family of transcription fact ors that are important for the coordinate expression of various cytokines a nd immunoregulatory cell surface molecules in T cells and other types of ce lls in the immune system. In addition, analysis of gene disrupted mice reve aled that some members of NFAT family are important for the development of myocardium, myocardial hypertrophy, and mesenchymal stem cells. NFAT family proteins have two conserved domains, the NFAT Homology Domain (NHD) and th e Rel Similarity Domain (RSD). The RSD is DNA binding and AP-1 interacting domain which has structural similarity to the Rel Homology Region, the DNA binding domain of Rel family proteins. The NHD is a regulatory domain requi red for the Ca regulated translocation of NFAT. We report here the isolatio n and initial characterization of a novel RSD containing protein designated NFATz. NFATz has a RSD but no NHD. NFATz protein is localized in the nucle us without Ca signal. There is no detectable binding to a typical NFAT site even in the presence of AP-1, and it is not capable of activating transcri ption through the NFAT site. The chromosomal location determined by FISH re vealed that NFATz and NFATx genes are in the Same region. (C) 2000 Academic Press.