Cationic polyamines such as spermidine and spermine are critical in all forms of life, as they regulate the function of biological macromolecules. Intracellular polyamine metabolism is regulated by reversible acetylation and dysregulated polyamine metabolism is associated with neoplastic diseases such as colon cancer, prostate cancer and neuroblastoma. Here we report that histone deacetylase 10 (HDAC10) is a robust polyamine deacetylase, using recombinant enzymes from Homo sapiens (human) and Danio rerio (zebrafish). The 2.85 Å-resolution crystal structure of zebrafish HDAC10 complexed with a transition-state analogue inhibitor reveals that a glutamate gatekeeper and a sterically constricted active site confer specificity for N8-acetylspermidine hydrolysis and disfavour acetyllysine hydrolysis. Both HDAC10 and spermidine are known to promote cellular survival through autophagy. Accordingly, this work sets a foundation for studying the chemical biology of autophagy through the structure-based design of inhibitors that may also serve as new leads for cancer chemotherapy.

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.

Background:The six human SET1 family core complexes catalyze methylation of histone H3 lysine 4 (H3K4). Results: Different SET1 family core complexes catalyze different levels of H3K4 methylation. Conclusion: Product specificity of the SET1 family is correlated with evolutionary lineage. Significance: Core complex subunits differentially regulate the product specificity of different SET1 family members.

Highlights d Histone lysine crotonylation (Kcr) oscillates in the yeast metabolic cycle (YMC) d Deregulation of crotonyl-CoA metabolism results in YMC defects d Taf14, a histone Kcr reader, is needed for transcription oscillations in the YMC d Kcr reading by Taf14 reduces growth gene expression during nutrient limitation

The yeast Set2 histone methyltransferase is a critical enzyme that plays a number of key roles in gene transcription and DNA repair. Recently, the human homologue, SETD2, was found to be recurrently mutated in a significant percentage of renal cell carcinomas, raising the possibility that the activity of SETD2 is tumorsuppressive. Using budding yeast and human cell line model systems, we examined the functional significance of two evolutionarily conserved residues in SETD2 that are recurrently mutated in human cancers. Whereas one of these mutations (R2510H), located in the Set2 Rpb1 interaction domain, did not result in an observable defect in SETD2 enzymatic function, a second mutation in the catalytic domain of this enzyme (R1625C) resulted in a complete loss of histone H3 Lys-36 trimethylation (H3K36me3). This mutant showed unchanged thermal stability as compared with the wild type protein but diminished binding to the histone H3 tail. Surprisingly, mutation of the conserved residue in Set2 (R195C) similarly resulted in a complete loss of H3K36me3 but did not affect dimethylated histone H3 Lys-36 (H3K36me2) or functions associated with H3K36me2 in yeast. Collectively, these data imply a critical role for Arg-1625 in maintaining the protein interaction with H3 and specific H3K36me3 function of this enzyme, which is conserved from yeast to humans. They also may provide a refined biochemical explanation for how H3K36me3 loss leads to genomic instability and cancer.Cancer is increasingly characterized by alterations in chromatin-modifying enzymes (1). SETD2, a non-redundant histone H3 lysine 36 (H3K36) 4 methyltransferase (2), has been found to be mutated in a growing list of tumor types, most notably in clear cell renal cell carcinoma (ccRCC) (1, 3, 4), but also in high grade gliomas (5), breast cancer (6), bladder cancer (7), and acute lymphoblastic leukemia (8 -10). Recent studies exploring intratumor heterogeneity in ccRCC identified distinct mutations in SETD2 from spatially distinct subsections of an individual tumor, suggesting that mutation of SETD2 is a critical and selected event in ccRCC cancer progression (11). Mutations in SETD2 are predominantly inactivating, such as early nonsense or frameshift mutations, which lead to nonfunctional protein and global loss of H3K36 trimethylation (H3K36me3) (4,11,12). Missense mutations tend to cluster in two domains (1,4,12,13): the SET domain, which catalyzes H3K36me3 (14), and the Set2 Rpb1 interaction (SRI) domain, which mediates the interaction between SETD2 and the hyperphosphorylated form of RNA polymerase II (RNAPII) (13).SETD2 and its yeast counterpart, Set2, both associate with RNAPII in a co-transcriptional manner (13,15,16). In yeast, Set2 mediates all H3K36 methylation states (H3K36me1/me2/ me3) (17) and regulates the recruitment of chromatin-remodeling enzymes (Isw1b) and a histone deacetylase (Rpd3) (18) that functions to keep gene bodies deacetylated, thereby maintaining a more compact chromatin structure (19,20) that is more resistant to inappropr...

Mixed Lineage Leukemia 1 (MLL1) protein is a member of the SET1 (or MLL) family of histone methyltransferases. In humans, this family consists of six members: MLL1-4, SETd1A, and SETd1B (1-8). The SET1 family catalyzes methylation of histone 3 lysine 4 (H3K4), 3 an epigenetic mark that is associated with active transcription (9 -12). The human SET1 family is composed of large proteins with several well characterized functional domains involved in chromatin binding and protein-protein interactions (13, 14) (Fig. 1A). Although some of these domains differ among family members, all share a C-terminal SET (suppressor of variegation, enhancer of Zeste, trithorax) domain that confers H3K4 methyltransferase activity (15). Like many chromatin-modifying enzymes, the SET1 family works as part of multiprotein complexes that contain binding partners involved in enzymatic regulation and gene targeting. Although the majority of isolated SET1 family SET domains catalyze weak H3K4 monomethylation (H3K4me1), enhanced methylation is observed in the context of a "core complex" (16). The minimal core complex required for enhanced methylation is composed of the SET1/MLL SET domain and a subcomplex called WRAD (WD-40 repeat protein 5 (WDR5), retinoblastoma-binding protein 5 (RbBP5), absent small homeotic 2-like (ASH2L), and dumpy-30 (DPY-30)) (17)(18)(19)(20). Interestingly, SET1 family core complexes preferentially catalyze different levels of H3K4 methylation in a manner that correlates with their evolutionary lineage (16). Whereas SETd1A/B core complexes catalyze mono-, di-, and trimethylation of H3K4 (H3K4me1, H3K4me2, and H3K4me3, respectively), the MLL1 and MLL4 (also known as MLL2) core complexes predominantly catalyze mono-and dimethylation (16). In contrast, MLL2 and MLL3 core complexes catalyze predominantly H3K4 monomethylation (16). In cells, different levels of H3K4 methylation are localized to distinct genomic regions and are associated with distinct functional outcomes (21-23). Assembly of the MLL1 core complex requires a direct interaction between MLL1 and WDR5, whereby WDR5 acts to stabilize the interaction between the MLL1 SET domain and the RbBP5/ASH2L heterodimer (18,24). The MLL1-WDR5 interaction occurs via the conserved Win (WDR5 interaction) * This work was supported, in whole or in part, by the National Institutes of Health Grant R01CA140522 (to M. S. C.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

BackgroundHistone posttranslational modifications (PTMs) function to regulate chromatin structure and function in part through the recruitment of effector proteins that harbor specialized “reader” domains. Despite efforts to elucidate reader domain–PTM interactions, the influence of neighboring PTMs and the target specificity of many reader domains is still unclear. The aim of this study was to use a high-throughput histone peptide microarray platform to interrogate 83 known and putative histone reader domains from the chromo and Tudor domain families to identify their interactions and characterize the influence of neighboring PTMs on these interactions. ResultsNearly a quarter of the chromo and Tudor domains screened showed interactions with histone PTMs by peptide microarray, revealing known and several novel methyllysine interactions. Specifically, we found that the CBX/HP1 chromodomains that recognize H3K9me also recognize H3K23me2/3—a poorly understood histone PTM. We also observed that, in addition to their interaction with H3K4me3, Tudor domains of the Spindlin family also recognized H4K20me3—a previously uncharacterized interaction. Several Tudor domains also showed novel interactions with H3K4me as well.ConclusionsThese results provide an important resource for the epigenetics and chromatin community on the interactions of many human chromo and Tudor domains. They also provide the basis for additional studies into the functional significance of the novel interactions that were discovered.Electronic supplementary materialThe online version of this article (doi:10.1186/s13072-017-0117-5) contains supplementary material, which is available to authorized users.

The Mixed Lineage Leukemia-1 (MLL1) enzyme is a histone H3 lysine 4 (H3K4) monomethyltransferase and has served as a paradigm for understanding the mechanism of action of the human SET1 family of enzymes that include MLL1–4, and SET1d1a,b. Dimethylation of H3K4 requires a sub-complex including WDR5, RbBP5, Ash2L, and DPY-30 (WRAD), which binds to each SET1 family member forming a minimal core complex that is required for multiple lysine methylation. We recently demonstrated that WRAD is a novel histone methyltransferase that preferentially catalyzes H3K4 dimethylation in a manner that is dependent on an unknown non-active site surface from the MLL1 SET domain. Recent genome sequencing studies have identified a number of human disease-associated missense mutations that localize to the SET domains of several MLL family members. In this investigation, we mapped many of these mutations onto the three-dimensional structure of the SET domain and noticed that a subset of MLL2 (KMT2D, ALR, MLL4)-associated Kabuki syndrome (KS) missense mutations map to a common solvent-exposed surface that is not expected to alter enzymatic activity. We introduced these mutations into the MLL1 SET domain and observed that all are defective for H3K4 dimethylation by the MLL1 core complex, which is associated with a loss of the ability of MLL1 to interact with WRAD or with the RbBP5-Ash2L heterodimer. Our results suggest that amino acids from this surface, which we term the Kabuki interaction surface or (KIS), are required for formation of a second active site within SET1 family core complexes.