Novel cellular regulatory mechanisms governing SWI/SNF activity

Project Summary In mammals, the SWI/SNF family of chromatin remodelers, known as canonical BAF (cBAF), PBAF, and GBAF complexes, are conserved ATP-dependent chromatin remodelers that generate genomic accessibility for DNA- templated processes. Due to their essential roles in diverse cellular pathways, these complexes make many important contributions to normal function and several disease states. Unfortunately, the cellular mechanisms by which SWI/SNF family complexes are themselves directly regulated by cellular signals remains poorly understood. Additionally, these complexes are known to coordinate their activities with many other chromatin remodelers, however the molecular features that mediate this coordination remain murky. Improved understanding of these issues would provide new opportunities to control nuclear activities in normal and disease states. To address these challenges, we have designed experiments that integrate new tools in epigenetics, cell biology, chemical biology, and microscopy. Our efforts leverage the ability to rapidly manipulate cellular signals and SWI/SNF activity in living cells to identify acute primary mechanisms. In addition to rapid perturbations, we have also designed rigorous assays that permit us to similarly measure immediate outcomes using epigenomics, proteomics, and live-cell microscopy. We will use these tools to answer essential questions about ATP- dependent chromatin remodeling specificity, including: (1) How do cellular signals influence SWI/SNF binding partner selection? (2) What pathways govern the dynamic spatial targeting of these complexes within subnuclear volumes? (3) How do these complexes coordinate remodeling activity with other chromatin regulators through non-catalytic interactions? Revealing the cellular mechanisms that influence these essential regulators may enable new interventions for rational control of gene expression patterns in diverse contexts.