DNA damage-binding protein 1

Author(s):  
Keyword(s):  
2011 ◽  
Vol 286 (22) ◽  
pp. 19229-19236 ◽  
Author(s):  
Laura A. Lindsey-Boltz ◽  
Aziz Sancar

The ataxia-telangiectasia mutated and RAD3-related (ATR) kinase initiates DNA damage signaling pathways in human cells after DNA damage such as that induced upon exposure to ultraviolet light by phosphorylating many effector proteins including the checkpoint kinase Chk1. The conventional view of ATR activation involves a universal signal consisting of genomic regions of replication protein A-covered single-stranded DNA. However, there are some indications that the ATR-mediated checkpoint can be activated by other mechanisms. Here, using the well defined Escherichia coli lac repressor/operator system, we have found that directly tethering the ATR activator topoisomerase IIβ-binding protein 1 (TopBP1) to DNA is sufficient to induce ATR phosphorylation of Chk1 in an in vitro system as well as in vivo in mammalian cells. In addition, we find synergistic activation of ATR phosphorylation of Chk1 when the mediator protein Claspin is also tethered to the DNA with TopBP1. Together, these findings indicate that crowding of checkpoint mediator proteins on DNA is sufficient to activate the ATR kinase.


2020 ◽  
Author(s):  
Chance Jones ◽  
Susan L Forsburg

AbstractStudies of genome stability have exploited visualization of fluorescently tagged proteins in live cells to characterize DNA damage, checkpoint, and repair responses. In this report, we describe a new tool for fission yeast, a tagged version of the end-binding protein Pku70 which is part of the KU protein complex. We compare Pku70 localization to other markers upon treatment to various genotoxins, and identify a unique pattern of distribution. Pku70 provides a new tool to define and characterize DNA lesions and the repair response.


2018 ◽  
Vol 115 (8) ◽  
pp. E1759-E1768 ◽  
Author(s):  
Jung-Kuei Chen ◽  
Wen-Ling Lin ◽  
Zhang Chen ◽  
Hung-wen Liu

Maintenance of genome integrity is critical for both faithful propagation of genetic information and prevention of mutagenesis induced by various DNA damage events. Here we report cold-inducible RNA-binding protein (CIRBP) as a newly identified key regulator in DNA double-strand break (DSB) repair. On DNA damage, CIRBP temporarily accumulates at the damaged regions and is poly(ADP ribosyl)ated by poly(ADP ribose) polymerase-1 (PARP-1). Its dissociation from the sites of damage may depend on its phosphorylation status as mediated by phosphatidylinositol 3-kinase-related kinases. In the absence of CIRBP, cells showed reduced γH2AX, Rad51, and 53BP1 foci formation. Moreover, CIRBP-depleted cells exhibited impaired homologous recombination, impaired nonhomologous end-joining, increased micronuclei formation, and higher sensitivity to gamma irradiation, demonstrating the active involvement of CIRBP in DSB repair. Furthermore, CIRBP depleted cells exhibited defects in DNA damage-induced chromatin association of the MRN complex (Mre11, Rad50, and NBS1) and ATM kinase. CIRBP depletion also reduced phosphorylation of a variety of ATM substrate proteins and thus impaired the DNA damage response. Taken together, these results reveal a previously unrecognized role for CIRBP in DSB repair.


2009 ◽  
Vol 187 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Jeffrey R. Skaar ◽  
Derek J. Richard ◽  
Anita Saraf ◽  
Alfredo Toschi ◽  
Emma Bolderson ◽  
...  

Human SSB1 (single-stranded binding protein 1 [hSSB1]) was recently identified as a part of the ataxia telangiectasia mutated (ATM) signaling pathway. To investigate hSSB1 function, we performed tandem affinity purifications of hSSB1 mutants mimicking the unphosphorylated and ATM-phosphorylated states. Both hSSB1 mutants copurified a subset of Integrator complex subunits and the uncharacterized protein LOC58493/c9orf80 (henceforth minute INTS3/hSSB-associated element [MISE]). The INTS3–MISE–hSSB1 complex plays a key role in ATM activation and RAD51 recruitment to DNA damage foci during the response to genotoxic stresses. These effects on the DNA damage response are caused by the control of hSSB1 transcription via INTS3, demonstrating a new network controlling hSSB1 function.


2005 ◽  
Vol 25 (15) ◽  
pp. 6509-6520 ◽  
Author(s):  
Lihong Chen ◽  
Changgong Li ◽  
Yu Pan ◽  
Jiandong Chen

ABSTRACT MDMX is a homolog of MDM2 that is critical for regulating p53 function during mouse development. MDMX degradation is regulated by MDM2-mediated ubiquitination. Whether there are other mechanisms of MDMX regulation is largely unknown. We found that MDMX binds to the casein kinase 1 alpha isoform (CK1α) and is phosphorylated by CK1α. Expression of CK1α stimulates the ability of MDMX to bind to p53 and inhibit p53 transcriptional function. Regulation of MDMX-p53 interaction requires CK1α binding to the central region of MDMX and phosphorylation of MDMX on serine 289. Inhibition of CK1α expression by isoform-specific small interfering RNA (siRNA) activates p53 and further enhances p53 activity after ionizing irradiation. CK1α siRNA also cooperates with DNA damage to induce apoptosis. These results suggest that CK1α is a functionally relevant MDMX-binding protein and plays an important role in regulating p53 activity in the absence or presence of stress.


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