NIMA-related kinase 7 interacts with Mat1 and is involved in the UV-induced DNA Damage Response
Nek7 is a serine/threonine kinase of the mammalian NIMA-related kinases (Neks) family, which members are involved in the regulation of the progression of the cell cycle. Although several Nek members have been associated with a range of cell cycle-related tasks, including DNA repair, a possible role of Nek7 in the DNA-damage response is so far unknown. Here, we employed in vitro and in vivo interaction assays to identify Mat1 as a specific Nek7 binding partner and substrate. In addition, we showed that Nek7 pulled down both CDK7 and cyclin H and directly phosphorylated Mat1, indicating that Nek7 may play a role in the regulation of the CAK complex. Furthermore, we showed that both Nek7 and Mat1 depletion led to an accumulation of cells in the S-phase, decreased cell proliferation and increased apoptosis. Notably, the mutational ablation of kinase Nek7 activity also induced increased apoptosis upon DNA damage. Collectively, our findings support the notion that Nek7 may cooperate with Mat1 in signal pathways that govern the cell cycle machinery including DDR, S-phase progression and apoptosis, and thereby can constitute an important novel player for in the context of cellular transformation and tumorigenesis.