Phosphorylation of the Human DNA Glycosylase NEIL2 Is Affected by Oxidative Stress and Modulates Its Activity

Abstract

The DNA glycosylase NEIL2 plays a central role in maintaining genome integrity, in particular during oxidative stress, by recognizing oxidized base lesions and initiating repair of these via the base excision repair (BER) pathway. Post-translational modifications are important molecular switches that regulate and coordinate the BER pathway, and thereby enable a rapid and fine-tuned response to DNA damage. Here, we report for the first time that human NEIL2 is regulated by phosphorylation. We demonstrate that NEIL2 is phosphorylated by the two kinases cyclin-dependent kinase 5 (CDK5) and protein kinase C (PKC) in vitro and in human SH-SY5Y neuroblastoma cells. The phosphorylation of NEIL2 by PKC causes a substantial reduction in NEIL2 repair activity, while CDK5 does not directly alter the enzymatic activity of NEIL2 in vitro, suggesting distinct modes of regulating NEIL2 function by the two kinases. Interestingly, we show a rapid dephosphorylation of NEIL2 in response to oxidative stress in SH-SY5Y cells. This points to phosphorylation as an important modulator of NEIL2 function in this cellular model, not least during oxidative stress.

Oxidative DNA Damage and Repair: Mechanisms, Mutations, and Relation to Diseases

“…Holst et al [ 6 ] have demonstrated for the first time that NEIL2 is phosphorylated by the two kinases in vitro and in human neuroblastoma cells: cyclin-dependent kinase 5 (CDK5) and protein kinase C (PKC). Post-translational modifications such as phosphorylation are generally known to serve as molecular switches providing a fast and fine-tuned response to acute oxidative stress.…”

“…Importantly, the authors demonstrated that this phosphorylation is rapidly reversed in response to oxidative stress rendered by treatment with hydrogen peroxide in human neuroblastoma cells. In paper [ 6 ], a working model of the phosphorylation state of NEIL2 is discussed. At a basal level, NEIL2 is phosphorylated by CDK5/PKC.…”

“…Dephosphorylation lifts the inhibitory effect of phosphorylation on NEIL2 activity and promotes NEIL2-initiated DNA repair response to counteract the threat to the genome. However, the mechanism of NEIL2 dephosphorylation and possible re-phosphorylation to its basal state after oxidative stress remains to be determined [ 6 ].…”