The discovery of new histone modifications is unfolding at startling rates, however, the identification of effectors capable of interpreting these modifications has lagged behind. Here we report the YEATS domain as an effective reader of histone lysine crotonylation – an epigenetic signature associated with active transcription. We show that the Taf14 YEATS domain engages crotonyllysine via a unique π-π-π-stacking mechanism and that other YEATS domains have crotonyllysine binding activity.

The YEATS domain, found in a number of chromatin-associated proteins, has recently been shown to have the capacity to bind histone lysine acetylation. Here, we show that the YEATS domain of Taf14, a member of key transcriptional and chromatin-modifying complexes in yeast, is a selective reader of histone H3 Lys9 acetylation (H3K9ac). Structural analysis reveals that acetylated Lys9 is sandwiched in an aromatic cage formed by F62 and W81. Disruption of this binding in cells impairs gene transcription and the DNA damage response. Our findings establish a highly conserved acetyllysine reader function for the YEATS domain protein family and highlight the significance of this interaction for Taf14.

Recognition of modified histones by “reader” proteins constitutes a key mechanism regulating diverse chromatin-associated processes important for normal and neoplastic development. We recently identified the YEATS domain as a novel acetyllysine-binding module; however, the functional importance of YEATS domain-containing proteins in human cancer remains largely unknown. Here, we show that the YEATS2 gene is highly amplified in human non-small cell lung cancer (NSCLC) and is required for cancer cell growth and survival. YEATS2 binds to acetylated histone H3 via its YEATS domain. The YEATS2-containing ATAC complex co-localizes with H3K27 acetylation (H3K27ac) on the promoters of actively transcribed genes. Depletion of YEATS2 or disruption of the interaction between its YEATS domain and acetylated histones reduces the ATAC complex-dependent promoter H3K9ac levels and deactivates the expression of essential genes. Taken together, our study identifies YEATS2 as a histone H3K27ac reader that regulates a transcriptional program essential for NSCLC tumorigenesis.

MYC is a major cancer driver but is documented to be a difficult therapeutic target itself. Here, we report on the biological activity, the structural basis, and therapeutic effects of the family of multitargeted compounds that simultaneously disrupt functions of two critical MYC-mediating factors through inhibiting the acetyllysine binding of BRD4 and the kinase activity of PI3K. We show that the dual-action inhibitor impairs PI3K/BRD4 signaling in vitro and in vivo and affords maximal MYC down-regulation. The concomitant inhibition of PI3K and BRD4 blocks MYC expression and activation, promotes MYC degradation, and markedly inhibits cancer cell growth and metastasis. Collectively, our findings suggest that the dualactivity inhibitor represents a highly promising lead compound for the development of novel anticancer therapeutics.T he MYC gene is frequently altered in human cancer. It encodes a transcription factor that binds to and regulates nearly 10-15% of genes in the human genome (1-3). The MYC targets mediate fundamental biological processes necessary for cell survival and general well-being, ranging from gene-expression and cell-cycle programs to cell proliferation and response to DNA damage, thereby establishing MYC as a global transcriptional regulator. MYC is overexpressed or amplified in many human cancers, which results in genome instability and deregulation of an array of signaling pathways responsible for malignant transformation. MYC expression level as well as synthesis, stability, and posttranslational modifications (PTMs) of the MYC protein are tightly regulated via several pathways, including PI3K-AKTmTOR and RAS-MAPK (4). Particularly, PI3K activation blocks MYC degradation through inhibiting GSK3β-dependent MYC phosphorylation at threonine 58, elevating MYC levels and inducing MYC-dependent oncogenic programs (4, 5).MYC gene expression has recently been linked to the activity of the BET (bromodomains and extraterminal domain) family of transcriptional coactivators (6-9). The BET protein BRD4 is found enriched at MYC and other oncogenes superenhancer and promoter regions, and transcriptional silencing of MYC coincides with the release of BET proteins from its locus, indicating that BET proteins can regulate MYC expression (10, 11). BRD4 itself is linked to multiple human malignancies: It forms chromosomal translocations in squamous carcinoma and NUT midline carcinoma, plays a role in progression of acute myeloid leukemia, and is up-regulated in breast cancer (7,(12)(13)(14). BRD4 contains a pair of bromodomains (BDs) that belong to the family of evolutionarily conserved structural modules that recognize acetyllysine PTMs in histones and nonhistone proteins (15, 16). Interestingly, BD1 and BD2 of BRD4 have distinct acetyllysine binding functions (17). BD1 binds to diacetylated histones, including histone H4 diacetylated at lysine 5 and lysine 8 (H4K5acK8ac), and this interaction helps to recruit or stabilize BRD4-containing transcription complexes at target gene promoters and enhancers. The se...

The field of chromatin biology has been advancing at an accelerated pace. Recent discoveries of previously uncharacterized sites and types of post-translational modifications (PTMs) and the identification of new sets of proteins responsible for the deposition, removal, and reading of these marks continue raising the complexity of an already exceedingly complicated biological phenomenon. In this Perspective article we examine the biological importance of new types and sites of histone PTMs and summarize the molecular mechanisms of chromatin engagement by newly discovered epigenetic readers. We also highlight the imperative role of structural insights in understanding PTM–reader interactions and discuss future directions to enhance the knowledge of PTM readout.