Fig. 2. Roles of cyclic GMP-AMP (cGAMP) synthase (cGAS) in the nucleus. Recent studies indicate that cGAS is an abundantly found in the nucleus. Unlikely with the canonical role of cGAS at the cytoplasm in cGAMP production, cGAS also has known to involve in diverse processes occurring in the nucleus. cGAS at the nucleus involves in the formation of replication fork, DNA repair, chromatin remodeling, tumorigenesis, cell senescence, cell cycle regulation, and unrevealed other functions.