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Crystal structure of REV7(R124A/A135D) in complex with a Shieldin3 fragment
Structural highlights
FunctionMD2L2_HUMAN Adapter protein able to interact with different proteins and involved in different biological processes. Mediates the interaction between the error-prone DNA polymerase zeta catalytic subunit REV3L and the inserter polymerase REV1, thereby mediating the second polymerase switching in translesion DNA synthesis. Translesion DNA synthesis releases the replication blockade of replicative polymerases, stalled in presence of DNA lesions. May also regulate another aspect of cellular response to DNA damage through regulation of the JNK-mediated phosphorylation and activation of the transcriptional activator ELK1. Inhibits the FZR1- and probably CDC20-mediated activation of the anaphase promoting complex APC thereby regulating progression through the cell cycle. Regulates TCF7L2-mediated gene transcription and may play a role in epithelial-mesenchymal transdifferentiation.[1] [2] [3] [4] [5] Publication Abstract from PubMedShieldin complex subunit 3 (SHLD3) is the apical subunit of a recently identified shieldin complex and plays a critical role in DNA double-strand break (DSB) repair. To fulfill its function in DNA repair, SHLD3 interacts with the mitotic spindle assembly checkpoint protein REV7 homolog (REV7), but the details of this interaction remain obscure. Here, we present the crystal structures of REV7 in complex with SHLD3's REV7-binding domain (RBD) at 2.2-2.3 A resolutions. The structures revealed that the ladle-shaped RBD in SHLD3 uses its N-terminal loop and C-terminal alpha-helix (alphaC-helix) in its interaction with REV7. The N-terminal loop exhibited a structure similar to those previously identified in other REV7-binding proteins, whereas the less conserved alphaC-helix region adopted a distinct mode for binding REV7. In vitro and in vivo binding analyses revealed that the N-terminal loop and alphaC-helix are both indispensable for high-affinity REV7 binding (with low-nanomolar affinity), underscoring the crucial role of SHLD3 alphaC-helix in protein binding. Moreover, binding kinetics analyses revealed that the REV7 "safety-belt" region, which plays a role in binding other proteins, is essential for SHLD3-REV7 binding, as this region retards the dissociation of the RBD from the bound REV7. Together, the findings of our study reveal the molecular basis of the SHLD3-REV7 interaction and provide critical insights into how SHLD3 recognizes REV7. Structural basis for shieldin complex subunit 3-mediated recruitment of the checkpoint protein REV7 during DNA double-strand break repair.,Dai Y, Zhang F, Wang L, Shan S, Gong Z, Zhou Z J Biol Chem. 2019 Dec 3. pii: RA119.011464. doi: 10.1074/jbc.RA119.011464. PMID:31796627[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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