scholarly journals Human MLH1 Protein Participates in Genomic Damage Checkpoint Signaling in Response to DNA Interstrand Crosslinks, while MSH2 Functions in DNA Repair

PLoS Genetics ◽  
2008 ◽  
Vol 4 (9) ◽  
pp. e1000189 ◽  
Author(s):  
Qi Wu ◽  
Karen M. Vasquez
Keyword(s):  
Dna Repair ◽  
Checkpoint Signaling ◽  
Interstrand Crosslinks ◽  
Dna Interstrand Crosslinks ◽  
Genomic Damage ◽  
Mlh1 Protein

scholarly journals FANCD2-FANCI is a clamp stabilized on DNA by monoubiquitination during DNA repair

2019 ◽  
Author(s):  
Pablo Alcón ◽  
Shabih Shakeel ◽  
Ketan J. Patel ◽  
Lori A. Passmore
Keyword(s):  
Dna Repair ◽  
Cancer Susceptibility ◽  
Abnormal Development ◽  
Interstrand Crosslinks ◽  
Closed Conformation ◽  
Dna Crosslinks ◽  
Double Stranded Dna ◽  
Dna Interstrand Crosslinks ◽  
Insight Into ◽  
Crosslink Repair

Vertebrate DNA crosslink repair is a crucial process that excises toxic replication-blocking DNA interstrand crosslinks1. This pathway fails in the inherited human disease Fanconi anemia (FA), resulting in abnormal development, loss of blood production, and marked cancer susceptibility2. Numerous factors involved in crosslink repair have been identified, and mutations in their corresponding genes cause FA3. A biochemical description of how FA gene products might initiate the removal of DNA crosslinks is now emerging. However, structural insight into this vital process has been limited. Here, we use electron cryomicroscopy (cryoEM) to determine the structure of a key DNA crosslink repair factor – FANCD2 heterodimerized with FANCI (D2-I). Recombinant chicken D2-I adopts a conformation that is in agreement with the structure of its murine counter-part4. In contrast, the activated monoubiquitinated form of D2-I (ubD2-I) adopts an alternative closed conformation, creating a channel that encloses double-stranded DNA. Ubiquitin is positioned at the interface of FANCD2 and FANCI, and acts as a molecular pin to trap ubD2-I in the closed conformation, clamped on DNA. The new solvent-exposed interface around the monoubiquitination site is likely a platform for recruitment of other DNA repair factors. We also find that isolated FANCD2 is a dimer, but it adopts a closed conformation that is unable to bind DNA. When incubated with free FANCI, the FANCD2 homodimer exchanges to D2-I, acquiring DNA binding properties. This suggests an autoinhibitory mechanism that prevents FANCD2 activation on DNA until after assembly with FANCI. Together, our cryoEM and biochemical analysis suggests that D2-I is a clamp that is locked onto DNA by ubiquitin, and provides unanticipated new insight into the regulation and the initiation of DNA cross-link repair.

scholarly journals Structural basis of FANCD2 deubiquitination by USP1-UAF1

2020 ◽  
Author(s):  
Martin L. Rennie ◽  
Connor Arkinson ◽  
Viduth K. Chaugule ◽  
Rachel Toth ◽  
Helen Walden
Keyword(s):  
Dna Repair ◽  
Fanconi Anemia ◽  
Conformational Changes ◽  
Substrate Recognition ◽  
Structural Basis ◽  
Interstrand Crosslinks ◽  
Biochemical Assays ◽  
Dna Interstrand Crosslinks ◽  
Specific Protease ◽  
Ubiquitin Specific Protease

AbstractUbiquitin-Specific Protease 1 (USP1), together with the cofactor UAF1, acts during DNA repair processes to specifically to remove mono-ubiquitin signals. The mono-ubiquitinated FANCI-FANCD2 heterodimer is one such substrate and is involved in the repair of DNA interstrand crosslinks via the Fanconi Anemia pathway. Here we determine structures of human USP1-UAF1 with and without ubiquitin, and bound to mono-ubiquitinated FANCI-FANCD2 substrate. Crystal structures of USP1-UAF1 reveal plasticity in USP1 and key differences to USP12-UAF1 and USP46-UAF1. A cryoEM reconstruction of USP1-UAF1 in complex mono-ubiquitinated FANCI-FANCD2, highlights a highly orchestrated deubiquitination process with USP1-UAF1 driving conformational changes in the substrate. An extensive interface between UAF1 and FANCI, confirmed by mutagenesis and biochemical assays, provides a molecular explanation for their requirement despite neither being directly involved in catalysis. Overall, our data provide molecular details of USP1-UAF1 regulation and substrate recognition.

scholarly journals Regulation of the Fanconi Anemia DNA Repair Pathway by Phosphorylation and Monoubiquitination

Genes ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1763
Author(s):  
Masamichi Ishiai
Keyword(s):  
Dna Repair ◽  
Fanconi Anemia ◽  
Genome Stability ◽  
Short Review ◽  
Repair Pathway ◽  
Binding Partner ◽  
Interstrand Crosslinks ◽  
Pathway Activation ◽  
Dna Interstrand Crosslinks

The Fanconi anemia (FA) DNA repair pathway coordinates a faithful repair mechanism for stalled DNA replication forks caused by factors such as DNA interstrand crosslinks (ICLs) or replication stress. An important role of FA pathway activation is initiated by monoubiquitination of FANCD2 and its binding partner of FANCI, which is regulated by the ATM-related kinase, ATR. Therefore, regulation of the FA pathway is a good example of the contribution of ATR to genome stability. In this short review, we summarize the knowledge accumulated over the years regarding how the FA pathway is activated via phosphorylation and monoubiquitination.

scholarly journals trans-Fatty acids promote p53-dependent apoptosis triggered by cisplatin-induced DNA interstrand crosslinks via the Nox-RIP1-ASK1-MAPK pathway

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yusuke Hirata ◽  
Miki Takahashi ◽  
Yuto Yamada ◽  
Ryosuke Matsui ◽  
Aya Inoue ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Mapk Pathway ◽  
Regulatory Protein ◽  
Strand Break ◽  
Mitogen Activated Protein Kinase ◽  
Ros Generation ◽  
Apoptotic Pathway ◽  
Interstrand Crosslinks ◽  
Pathway Activation ◽  
Dna Interstrand Crosslinks

Abstracttrans-Fatty acids (TFAs) are food-derived fatty acids associated with various diseases including cardiovascular diseases. However, the underlying etiology is poorly understood. Here, we show a pro-apoptotic mechanism of TFAs such as elaidic acid (EA), in response to DNA interstrand crosslinks (ICLs) induced by cisplatin (CDDP). We previously reported that TFAs promote apoptosis induced by doxorubicin (Dox), a double strand break (DSB)-inducing agent, via a non-canonical apoptotic pathway independent of tumor suppressor p53 and apoptosis signal-regulating kinase (ASK1), a reactive oxygen species (ROS)-responsive kinase. However, here we found that in the case of CDDP-induced apoptosis, EA-mediated pro-apoptotic action was reversed by knockout of either p53 or ASK1, despite no increase in p53 apoptotic activity. Upon CDDP treatment, EA predominantly enhanced ROS generation, ASK1-p38/c-Jun N-terminal kinase (JNK) mitogen-activated protein kinase (MAPK) pathway activation, and ultimately cell death, all of which were suppressed either by co-treatment of the NADPH oxidase (Nox) inhibitor Apocynin, or by knocking out its regulatory protein, receptor-interacting protein 1 (RIP1). These results demonstrate that in response to CDDP ICLs, TFAs promote p53-dependent apoptosis through the enhancement of the Nox-RIP1-ASK1-MAPK pathway activation, providing insight into the diverse pathogenetic mechanisms of TFAs according to the types of DNA damage.

scholarly journals Differential functions of FANCI and FANCD2 ubiquitination stabilize ID2 complex on DNA

2020 ◽  
Author(s):  
Martin L. Rennie ◽  
Kimon Lemonidis ◽  
Connor Arkinson ◽  
Viduth K. Chaugule ◽  
Mairi Clarke ◽  
...  
Keyword(s):  
Fanconi Anemia ◽  
Large Scale ◽  
The Other ◽  
Molecular Function ◽  
Post Translational Modifications ◽  
Hydrophobic Residues ◽  
Interstrand Crosslinks ◽  
Double Stranded Dna ◽  
Dna Interstrand Crosslinks ◽  
Lysine Residues

AbstractThe Fanconi Anemia (FA) pathway is a dedicated pathway for the repair of DNA interstrand crosslinks, and which is additionally activated in response to other forms of replication stress. A key step in the activation of the FA pathway is the monoubiquitination of each of the two subunits (FANCI and FANCD2) of the ID2 complex on specific lysine residues. However, the molecular function of these modifications has been unknown for nearly two decades. Here we find that ubiquitination of FANCD2 acts to increase ID2’s affinity for double stranded DNA via promoting/stabilizing a large-scale conformational change in the complex, resulting in a secondary “Arm” ID2 interphase encircling DNA. Ubiquitination of FANCI, on the other hand, largely protects the ubiquitin on FANCD2 from USP1/UAF deubiquitination, with key hydrophobic residues of FANCI’s ubiquitin being important for this protection. In effect, both of these post-translational modifications function to stabilise a conformation in which the ID2 complex encircles DNA.

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