Emerin Phosphorylation during the Early Phase of the Oxidative Stress Response Influences Emerin-BAF Interaction and BAF Nuclear Localization.

ABSTRACT

Reactive Oxygen Species (ROS) are reactive molecules required for the maintenance of physiological functions. Oxidative stress arises when ROS production exceeds the cellular ability to eliminate such molecules. In this study, we showed that oxidative stress induces post-translational modification of the inner nuclear membrane protein emerin. In particular, emerin is phosphorylated at the early stages of the oxidative stress response, while protein phosphorylation is abolished upon recovery from stress. A finely tuned balance between emerin phosphorylation and O-GlcNAcylation seems to govern this dynamic and modulates emerin-BAF interaction and BAF nucleoplasmic localization during the oxidative stress response. Interestingly, emerin post-translational modifications, similar to those observed during the stress response, are detected in cells bearing LMNA gene mutations and are characterized by a free radical generating environment. On the other hand, under oxidative stress conditions, a delay in DNA damage repair and cell cycle progression is found in cells from Emery-Dreifuss Muscular Dystrophy type 1, which do not express emerin. These results suggest a role of the emerin-BAF protein platform in the DNA damage response aimed at counteracting the detrimental effects of elevated levels of ROS.