biostudies-literatureXuan FCPRITNational Cancer InstituteNCI NIH HHSNational Institutes of HealthNIGMS NIH HHS168414https://www.ebi.ac.uk/biostudies/studies/S-EPMC10957329biostudies-literatureUnknown436(7)The lysine acetyltransferase KAT5 is a pivotal enzyme responsible for catalyzing histone H4 acetylation in cells. In addition to its indispensable HAT domain, KAT5 also encompasses a conserved Tudor-knot domain at its N-terminus. However, the function of this domain remains elusive, with conflicting findings regarding its role as a histone reader. In our study, we have employed a CRISPR tiling array approach and unveiled the Tudor-knot motif as an essential domain for cell survival. The Tudor-knot domain does not bind to histone tails and is not required for KAT5's chromatin occupancy. However, its absence leads to a global reduction in histone acetylation, accompanied with genome-wide alterations in gene expression that consequently result in diminished cell viability. Mechanistically, we find that the Tudor-knot domain regulates KAT5's HAT activity on nucleosomes by fine-tuning substrate accessibility. In summary, our study uncovers the Tudor-knot motif as an essential domain for cell survival and reveals its critical role in modulating KAT5's catalytic efficiency on nucleosome and KAT5-dependent transcriptional programs critical for cell viability.Journal of molecular biologyThe Tudor-knot Domain of KAT5 Regulates Nucleosomal Substrate Acetylation.PMC10957329CA268440R01 CA204020CA204020GM137927R35 GM137927R01 CA268440R01 CA255506CA260666CA255506R01 CA260666RR160097Wen HHe WXuan FHuang MXuan HXu HShi XfalseThe Tudor-knot Domain of KAT5 Regulates Nucleosomal Substrate Acetylation.The lysine acetyltransferase KAT5 is a pivotal enzyme responsible for catalyzing histone H4 acetylation in cells. In addition to its indispensable HAT domain, KAT5 also encompasses a conserved Tudor-knot domain at its N-terminus. However, the function of this domain remains elusive, with conflicting findings regarding its role as a histone reader. In our study, we have employed a CRISPR tiling array approach and unveiled the Tudor-knot motif as an essential domain for cell survival. The Tudor-knot domain does not bind to histone tails and is not required for KAT5's chromatin occupancy. However, its absence leads to a global reduction in histone acetylation, accompanied with genome-wide alterations in gene expression that consequently result in diminished cell viability. Mechanistically, we find that the Tudor-knot domain regulates KAT5's HAT activity on nucleosomes by fine-tuning substrate accessibility. In summary, our study uncovers the Tudor-knot motif as an essential domain for cell survival and reveals its critical role in modulating KAT5's catalytic efficiency on nucleosome and KAT5-dependent transcriptional programs critical for cell viability.2024-01-01T00:00:00Z2024 Apr2026-06-27T03:21:54.843Z2025-07-04T03:05:53.344ZS-EPMC109573293814187410.1016/j.jmb.2023.168414