Identification and Functional Characterization of a Ku-binding Motif in Aprataxin Polynucleotide Kinase/Phosphatase-like Factor (APLF)

Shirodkar, Purnata; Fenton, Amanda L.; Li, Meng; Koch, Christine

doi:10.1074/jbc.m112.440388

Cited by 40 publications

(50 citation statements)

References 38 publications

(68 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Additionally, another region of the human Ku70 vWA domain in helix 4 was found to regulate DNA damage signaling to apoptosis [21]. Consistent with its predicted role as a protein-protein interaction surface, the vWA domain has been shown to mediate an interaction with both the telomere complex component telomere repeat binding factor 2 (TRF2) and NHEJ factor aprataxin and PNKP like factor (APLF) [20,24].…”

Section: Ku Structurementioning

confidence: 83%

The Ku heterodimer: Function in DNA repair and beyond

Fell

Schild-Poulter

2015

Mutation Research/Reviews in Mutation Research

220

216

View full text Add to dashboard Cite

Section: Ku Structurementioning

confidence: 83%

The Ku heterodimer: Function in DNA repair and beyond

Fell

Schild-Poulter

2015

Mutation Research/Reviews in Mutation Research

220

216

View full text Add to dashboard Cite

“…APLF, also known as Xip1, is a recently discovered DNA repair protein with two C-terminal PBZ domains, which are required for the recruitment of APLF to sites of DNA damage (31,32). Interestingly, APLF is known to associate with core NHEJ components such as XRCC4-DNA ligase IV and Ku proteins (33)(34)(35). It is thus tempting to speculate that the augmented Ku protein recruitment to chromatin by increased PARP-1 expression in human cancer cells may be via association with APLF that binds to the abundant PARylated chromatin via its PBZ domain carrying Ku.…”

Section: Discussionmentioning

confidence: 99%

FASN regulates cellular response to genotoxic treatments by increasing PARP-1 expression and DNA repair activity via NF-κB and SP1

Dong

Wang

et al. 2016

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Fatty acid synthase (FASN), the sole cytosolic mammalian enzyme for de novo lipid synthesis, is crucial for cancer cell survival and associates with poor prognosis. FASN overexpression has been found to cause resistance to genotoxic insults. Here we tested the hypothesis that FASN regulates DNA repair to facilitate survival against genotoxic insults and found that FASN suppresses NF-κB but increases specificity protein 1 (SP1) expression. NF-κB and SP1 bind to a composite element in the poly(ADP-ribose) polymerase 1 (PARP-1) promoter in a mutually exclusive manner and regulate PARP-1 expression. Up-regulation of PARP-1 by FASN in turn increases Ku protein recruitment and DNA repair. Furthermore, lipid deprivation suppresses SP1 expression, which is able to be rescued by palmitate supplementation. However, lipid deprivation or palmitate supplementation has no effect on NF-κB expression. Thus, FASN may regulate NF-κB and SP1 expression using different mechanisms. Altogether, we conclude that FASN regulates cellular response against genotoxic insults by up-regulating PARP-1 and DNA repair via NF-κB and SP1.fatty acid synthase | transcription regulation | DNA repair | drug resistance | radiation resistance F atty acid synthase (FASN) is the key mammalian enzyme required for de novo synthesis of palmitate. FASN expression and activity are largely suppressed by sufficient dietary fat in most normal nonadipose tissues but are abnormally elevated in many human cancers and associated with poor prognosis (1). FASN association with poor prognosis may derive in part from FASN function in drug resistance during chemotherapy. Indeed, it has been found that FASN expression and/or activity was increased in drug-selected and -resistant breast (2) and pancreatic (3) cancer cells. It was also found that FASN overexpression causes cellular resistance to DNA-damaging drugs such as doxorubicin and mitoxantrone but not to microtubule modulators such as vinblastine and paclitaxel (4). Decreased ceramide production following doxorubicin treatment via suppression of tumor necrosis factor (TNF)-α production is believed to be one of the mechanisms of FASN-induced resistance to doxorubicin (4).The observation that FASN increases resistance to genotoxic drugs prompted us to hypothesize that FASN overexpression may up-regulate DNA damage response/repair pathways. In this study, we tested this hypothesis with a focus on the repair of DNA double-strand breaks (DSBs), which are commonly induced by the anticancer drugs doxorubicin and mitoxantrone and ionizing radiation. In mammalian cells, DSBs are repaired mainly via homologous recombination (HR) and nonhomologous end-joining (NHEJ) pathways. NHEJ is the predominant form of DSB repair because it occurs during all phases of the cell cycle whereas HR only initiates at late G1 and S phases (5). Hence, we examined NHEJ repair of DSBs and found that FASN up-regulates NHEJ activity and repair of DSBs by increasing poly(ADP-ribose) polymerase 1 (PARP-1) expression via increasing the expression of spec...

show abstract

“…As noted below ( III.iv) , APLF may also foster substrate or factor channeling between NHEJ and BER. APLF is capable of direct protein-protein interactions with phosphorylated XRCC4 through APLF’s N-terminal FHA domain [41, 42], as well as Ku through a more central region in APLF [14, 66] (Fig. 3A).…”

Section: Nhej Is a Multi-protein Machinementioning

confidence: 99%

“…However, APLF could also promote dynamic changes in the stability and composition of complexes present at strand breaks; its PBZ domains can interact with uncharacterized factors already present at the strand break after they are modified by PAR [67, 69]. APLF may also interact simultaneously with XRCC1 or XRCC4 [41, 42], Ku, [14, 66] and PAR [69], thus acting as a physical and inducible link between multiple strand break repair pathways (e.g. NHEJ, SSBR, Alt-EJ).…”

Section: Strategies For Resolving Endsmentioning

confidence: 99%