Dataset Information

ATM regulates NF-?B-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment.

ABSTRACT: Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKK? association with ubiquitin and its complex formation with ATM for nuclear export. Activated cytoplasmic ATM is involved in the selective recruitment of the E3-ubiquitin ligase ?-TrCP to phospho-I?B? proteosomal degradation. Importantly, ATM binds and activates the catalytic subunit of protein kinase A (PKAc), ribosmal S6 kinase that controls RelA Ser 276 phosphorylation. In ATM knockdown cells, TNF-induced RelA Ser 276 phosphorylation is significantly decreased. We further observed decreased binding and recruitment of the transcriptional elongation complex containing cyclin dependent kinase-9 (CDK9; a kinase necessary for triggering transcriptional elongation) to promoters of NF-?B-dependent immediate-early cytokine genes, in ATM knockdown cells. We conclude that ATM is a nuclear damage-response signal modulator of TNF-induced NF-?B activation that plays a key scaffolding role in I?B? degradation and RelA Ser 276 phosphorylation. Our study provides a mechanistic explanation of decreased innate immune response associated with A-T mutation.

SUBMITTER: Fang L

PROVIDER: S-EPMC4117761 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment.

Fang Ling L Choudhary Sanjeev S Zhao Yingxin Y Edeh Chukwudi B CB Yang Chunying C Boldogh Istvan I Brasier Allan R AR

Nucleic acids research 20140623 13

Ataxia-telangiectasia mutated (ATM), a member of the phosphatidylinositol 3 kinase-like kinase family, is a master regulator of the double strand DNA break-repair pathway after genotoxic stress. Here, we found ATM serves as an essential regulator of TNF-induced NF-kB pathway. We observed that TNF exposure of cells rapidly induced DNA double strand breaks and activates ATM. TNF-induced ROS promote nuclear IKKγ association with ubiquitin and its complex formation with ATM for nuclear export. Activ ...[more]

PMID: 24957606

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Project description:The replication and transcription activator (RTA) of Kaposi's sarcoma-associated herpesvirus (KSHV), K-RTA, is a lytic switch protein that moderates the reactivation process of KSHV latency. By mass spectrometric analysis of affinity purified K-RTA, we showed that Thr-513 or Thr-514 was the primary in vivo phosphorylation site. Thr-513 and Thr-514 are proximal to the nuclear localization signal ((527)KKRK(530)) and were previously hypothesized to be target sites of Ser/Thr kinase hKFC. However, substitutions of Thr with Ala at 513 and 514 had no effect on K-RTA subcellular localization or transactivation activity. By contrast, replacement of Ser with Ala at Ser-634 and Ser-636 located in a Ser/Pro-rich region of K-RTA, designated as S634A/S636A, produced a polypeptide with ∼10 kDa shorter in molecular weight and reduced transactivation in a luciferase reporter assay relative to the wild type. In contrast to prediction, the decrease in molecular weight was not due to lack of phosphorylation because the overall Ser and Thr phosphorylation state in K-RTA and S634A/S636A were similar, excluding that Ser-634 or Ser-636 motif served as docking sites for consecutive phosphorylation. Interestingly, S634A/S636A lost ∼30% immuno-reactivity to MPM2, an antibody specific to pSer/pThr-Pro motif, indicating that (634)SPSP(637) motif was in vivo phosphorylated. By in vitro kinase assay, we showed that K-RTA is a substrate of CDK9, a Pro-directed Ser/Thr kinase central to transcriptional regulation. Importantly, the capability of K-RTA in associating with endogenous CDK9 was reduced in S634A/S636A, which suggested that Ser-634 and Ser-636 may be involved in CDK9 recruitment. In agreement, S634A/S636A mutant exhibited ∼25% reduction in KSHV lytic cycle reactivation relative to that by the wild type K-RTA. Taken together, our data propose that Ser-634 and Ser-636 of K-RTA are phosphorylated by host transcriptional kinase CDK9 and such a process contributes to a full transcriptional potency of K-RTA.

Dataset Information

ATM regulates NF-?B-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment.

Publications

ATM regulates NF-κB-dependent immediate-early genes via RelA Ser 276 phosphorylation coupled to CDK9 promoter recruitment.

Similar Datasets

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