DNA-PK: gatekeeper for IKK γ/NEMO nucleocytoplasmic shuttling in genotoxic stress-induced NF-kappaB activation.

DNA-PK: gatekeeper for IKKγ/NEMO nucleocytoplasmic shuttling in genotoxic stress-induced NF-kappaB activation. Cell Mol Life Sci. 2020 Jan 13;: Authors: Medunjanin S, Putzier M, Nöthen T, Weinert S, Kähne T, Luani B, Zuschratter W, Braun-Dullaeus RC Abstract The transcription factors of the nuclear factor κB (NF-κB) family play a pivotal role in the cellular response to DNA damage. Genotoxic stress-induced activation of NF-κB differs from the classical canonical pathway by shuttling of the NF-κB Essential Modifier (IKKγ/NEMO) subunit through the nucleus. Here, we show that DNA-dependent protein kinase (DNA-PK), an enzyme involved in DNA double-strand break (DSB) repair, triggers the phosphorylation of NEMO by genotoxic stress, thereby enabling shuttling of NEMO through the nucleus with subsequent NF-κB activation. We identified serine 43 of NEMO as a DNA-PK phosphorylation site and point mutation of this serine to alanine led to a complete block of NF-κB activation by ionizing radiation (IR). Blockade of DNA-PK by a specific shRNA or by DNA-PKcs-deficient cells abrogated NEMO entry into the nucleus, as well. Accordingly, SUMOylation of NEMO, a prerequisite of nuclear NEMO, was abolished. Based on these observations, we propose a model in which NEMO phosphorylation by DNA-PK provides the first step in the nucleocytoplasmic trafficking of NEMO. PMID: 31932854 [PubMed - as supplied by publisher]
Source: Cellular and Molecular Life Sciences : CMLS - Category: Cytology Authors: Tags: Cell Mol Life Sci Source Type: research