CBP and p300 are histone acetyltransferases (HATs) that associate with and acetylate transcriptional regulators and chromatin. Mutations in their catalytic 'cores' are linked to genetic disorders, including cancer. Here we present the 2.8-Å crystal structure of the catalytic core of human p300 containing its bromodomain, CH2 region and HAT domain. The structure reveals that the CH2 region contains a discontinuous PHD domain interrupted by a RING domain. The bromodomain, PHD, RING and HAT domains adopt an assembled configuration with the RING domain positioned over the HAT substrate-binding pocket. Disease mutations that disrupt RING attachment led to upregulation of HAT activity, thus revealing an inhibitory role for this domain. The structure provides a starting point for understanding how chromatin-substrate targeting and HAT regulation are coupled and why mutations in the p300 core lead to dysregulation.

Lipids are important cellular metabolites, with a wide range of structural and functional diversity. Many operate as signaling molecules. Lipids though have rarely been studied in large-scale interaction screen; they are poorly represented in current biological networks.Here, we describe the use of miniaturized lipid–arrays for the large-scale study of protein–lipid interactions. In yeast, we show general feasibility with a systematic screen implying 172 proteins. We report 530 protein–lipid associations, the majority is novel and several were validated using other techniques.The screen uncovers numerous insights into lipid function in yeast and equivalent systems in humans. It revealed (i) previously undetected cryptic lipid-binding domains, (ii) series of new cellular targets for sphingolipids and (iii) new ligands for some PH domains that can cooperatively bind additional lipids and work as coincidence sensor to integrate both phosphatidylinositol phosphates and sphingolipid signaling pathways.The significant number of biological insights uncovered shows that even major classes of metabolites have been insufficiently studied. This illustrates the general relevance of such systematic screens and calls for further system-wide analyses.