8esc | pdb_00008esc
Structure of the Yeast NuA4 Histone Acetyltransferase Complex
Structural highlights
FunctionTRA1_YEAST Essential component of histone acetyltransferase (HAT) complexes, which serves as a target for activators during recruitment of HAT complexes. Essential for vegetative growth. Functions as a component of the transcription regulatory histone acetylation (HAT) complexes SAGA, SALSA and SLIK. SAGA is involved in RNA polymerase II-dependent transcriptional regulation of approximately 10% of yeast genes. At the promoters, SAGA is required for recruitment of the basal transcription machinery. It influences RNA polymerase II transcriptional activity through different activities such as TBP interaction (SPT3, SPT8 and SPT20) and promoter selectivity, interaction with transcription activators (GCN5, ADA2, ADA3 and TRA1), and chromatin modification through histone acetylation (GCN5) and deubiquitination (UBP8). SAGA acetylates nucleosomal histone H3 to some extent (to form H3K9ac, H3K14ac, H3K18ac and H3K23ac). SAGA interacts with DNA via upstream activating sequences (UASs). SALSA, an altered form of SAGA, may be involved in positive transcriptional regulation. SLIK is proposed to have partly overlapping functions with SAGA. It preferentially acetylates methylated histone H3, at least after activation at the GAL1-10 locus.[1] [2] Publication Abstract from PubMedThe NuA4 protein complex acetylates histones H4 and H2A to activate both transcription and DNA repair. We report the 3.1-A resolution cryo-electron microscopy structure of the central hub of NuA4, which flexibly tethers the histone acetyltransferase (HAT) and Trimer Independent of NuA4 involved in Transcription Interactions with Nucleosomes (TINTIN) modules. The hub contains the large Tra1 subunit and a core that includes Swc4, Arp4, Act1, Eaf1, and the C-terminal region of Epl1. Eaf1 stands out as the primary scaffolding factor that interacts with the Tra1, Swc4, and Epl1 subunits and contributes the conserved HSA helix to the Arp module. Using nucleosome-binding assays, we find that the HAT module, which is anchored to the core through Epl1, recognizes H3K4me3 nucleosomes with hyperacetylated H3 tails, while the TINTIN module, anchored to the core via Eaf1, recognizes nucleosomes that have hyperacetylated H2A and H4 tails. Together with the known interaction of Tra1 with site-specific transcription factors, our data suggest a model in which Tra1 recruits NuA4 to specific genomic sites then allowing the flexible HAT and TINTIN modules to select nearby nucleosomes for acetylation. Structure and flexibility of the yeast NuA4 histone acetyltransferase complex.,Zukin SA, Marunde MR, Popova IK, Soczek KM, Nogales E, Patel AB Elife. 2022 Oct 20;11. pii: 81400. doi: 10.7554/eLife.81400. PMID:36263929[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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