Download MendeleyStructural basis of complex assembly and nucleosome recognition by the chromatin remodeling ncBAF complex.
Xu, W., Ma, S., Li, Y., Li, M., Li, C., Yin, Y., Li, Q., Cheng, J., Chen, Y.(2026) J Mol Cell Biol
- PubMed: 42377898 Search on PubMed
- DOI: https://doi.org/10.1093/jmcb/mjag020
- Primary Citation Related Structures:
21VV, 21WA, 21WC - PubMed Abstract:
BRG1/BRM-associated factor (BAF)-family chromatin remodelers regulate transcription and genome organization by repositioning nucleosomes. The human non-canonical BAF (ncBAF) complex is uniquely defined by the presence of BRD9 and GLTSCR1/GLTSCR1L, as well as the absence of the ARID1/2 scaffold and the canonical nucleosome-binding module found in cBAF and PBAF. How ncBAF assembles and engages nucleosomes remains elusive. Here, we present a cryo-EM structure of ncBAF bound to a nucleosome, integrated with biochemical assays and crosslinking mass spectrometry analyses. The ncBAF complex adopts a three-module architecture comprising an ATPase motor module, a repositioned actin-related protein (ARP) module, and a highly flexible Base module. The ncBAF-specific subunits BRD9 and GLTSCR1L are largely dispensable for complex assembly and nucleosome remodeling. Instead, BCL7A directly engages the H2A-H2B acidic patch and the H2A N-terminal tail, providing a structural substitute for SMARCB1 in stimulating remodeling activity. These findings reveal how ncBAF compensates for the loss of the canonical nucleosome-binding module through modular reorganization, providing a structural framework for understanding ncBAF-mediated chromatin regulation and its roles in development and disease.
- Key Laboratory of Epigenetic Regulation and Intervention, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences; University of Chinese Academy of Sciences, Shanghai 200031, China.
Organizational Affiliation:
