Decoding the Assembly and Function of Paralogue Specific SIN3A and SIN3B Human Chromatin Remodeling Complexes and Networks - ABSTRACT Paralog switching in chromatin remodeling complexes plays a key role in development and loss of regulatory control over chromatin paralog functions is closely linked to many types of cancer. Human SIN3A and SIN3B are amongst this class of important chromatin remodeling paralogs. SIN3A mutations are considered driver mutations in uterine corpus endometrial carcinoma, and both SIN3A and SIN3B haploinsufficiency linked to human neurodevelopmental disorders. Human SIN3A and SIN3B are members of several large multiprotein complexes involved in chromatin remodeling containing the histone deacetylase enzymes HDAC1 and HDAC2. While the overall members of the SIN3A and SIN3B complexes is largely known, the structure and function of specific complexes in these networks remain poorly understood. Furthermore, the precise targeting of gene repression by SIN3/HDAC-mediated histone deacetylation is likely controlled by the non-catalytic SIN3 subunits but also remains enigmatic. These fundamental gaps in knowledge regarding the structure and function of SIN3A and SIN3B containing complexes limit our ability to devise specific therapeutic interventions in cancer, for example. The overarching goal of the research in the laboratory is to understand the molecular mechanisms of how specific SIN3A and SIN3B complexes regulate gene expression and chromatin remodeling in normal and diseased human conditions. We are in a unique position to advance the understanding of these area of research based on my strong track record and long-standing expertise in chromatin remodeling and proteomics, assembled team of collaborators, and multidisciplinary approach. In our lab, we continually develop new proteomic technologies and apply them to chromatin remodeling complexes and networks. Here, we will use a comprehensive approach of affinity purification, enzyme kinetics, peptide synthesis, fluorescence microscopy, genomics, quantitative proteomics, cross linking mass spectrometry, and integrative structural modeling. Using these methodologies over the next five years, we will investigate 1) How are SIN3A and SIN3B complexes assembled, 2) What are the regulatory functions of specific subunits, 3) How do SIN3A complexes regulate specific transcription factor function, 4) What are the SIN3A and SIN3B networks in endometrial cells, and 5) How can we disrupt protein protein interactions in these complexes? This set of questions will go from a fundamental structure and function of these complexes to determining the role of specific complexes in important human cellular models. We will lay the foundation to address the gap in knowledge in the diversity and function of specific chromatin remodeling complexes. In addition, we will begin to develop new therapeutic strategies to target specific chromatin remodeling complexes. With this information in hand, we will be closer to our long-term goal and vision of designing peptide-based approaches to disrupt specific protein complexes as novel and specific cancer therapeutic agents.
