Phosphorylation of histone H2A or H2AX is an early and sensitive marker of DNA damage in eukaryotic cells, although mutation of the conserved damage-dependent phosphorylation site is well tolerated. Here, we show that H2A phosphorylation is required for cell-cycle arrest in response to DNA damage at the G1/S transition in budding yeast. Furthermore, we show that the tandem BRCT domain of Rad9 interacts directly with phosphorylated H2A in vitro and that a rad9 point mutation that abolishes this interaction results in in vivo phenotypes that are similar to those caused by an H2A phosphorylation site mutation. Remarkably, similar checkpoint defects are also caused by a Rad9 Tudor domain mutation that impairs Rad9 chromatin association already in undamaged cells. These findings indicate that constitutive Tudor domain-mediated and damage-specific BRCT domain-phospho-H2A-dependent interactions of Rad9 with chromatin cooperate to establish G1 checkpoint arrest.
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http://dx.doi.org/10.1038/sj.embor.7401036 | DOI Listing |
Protein-folding chaperone HSP90 buffers genetic variation in diverse organisms, but the clinical significance of HSP90 buffering in disease remains unclear. Here, we show that HSP90 buffers mutations in the BRCT domain of BRCA1. HSP90-buffered mutations encode protein variants that retain interactions with partner proteins and rely on HSP90 for protein stability and function in cell survival.
View Article and Find Full Text PDFbioRxiv
November 2024
Department of Immunology and Microbiology, The Scripps Research Institute, La Jolla, CA 92037 USA.
Numerous proteins perform their functions by transitioning between various structures. Understanding the conformational ensembles associated with these states is essential for uncovering crucial mechanistic aspects that regulate protein function. In this study, we utilized AlphaFold3 () to investigate the structural dynamics and mechanisms of enzymes involved in DNA homeostasis, using NAD-dependent Taq ligases and human DNA Ligase 1 as a case example.
View Article and Find Full Text PDFComput Struct Biotechnol J
December 2024
Department of Quantitative Health Sciences, Mayo Clinic, Rochester, MN, United States.
Biochim Biophys Acta Mol Basis Dis
January 2025
Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea. Electronic address:
There is evidence that BRCA1, particularly cytoplasmic BRCA1, plays a significant role in initiating apoptosis through various mechanisms. Maintaining the stability of BRCA1 in cancer cells may be a promising therapeutic strategy for breast cancer, especially in cases of triple-negative breast cancer (TNBC) lacking appropriate therapeutic targets. Previously, it was reported that cathepsin S (CTSS) interacts with the BRCT domain of BRCA1, leading to ubiquitin-mediated degradation.
View Article and Find Full Text PDFFront Oncol
September 2024
Department of Medical Oncology, School of Medicine and Surgery, University of Naples Federico II, Naples, Italy.
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