Download MendeleyMultistate structures of the MLL1-WRAD complex bound to H2B-ubiquitinated nucleosome.
Rahman, S., Hoffmann, N.A., Worden, E.J., Smith, M.L., Namitz, K.E.W., Knutson, B.A., Cosgrove, M.S., Wolberger, C.(2022) Proc Natl Acad Sci U S A 119: e2205691119-e2205691119
- PubMed: 36095189
- DOI: https://doi.org/10.1073/pnas.2205691119
- Primary Citation of Related Structures:
7UD5, 8DU4 - PubMed Abstract:
The human Mixed Lineage Leukemia-1 (MLL1) complex methylates histone H3K4 to promote transcription and is stimulated by monoubiquitination of histone H2B. Recent structures of the MLL1-WRAD core complex, which comprises the MLL1 methyltransferase, W DR5, R bBp5, A sh2L, and D PY-30, have revealed variability in the docking of MLL1-WRAD on nucleosomes. In addition, portions of the Ash2L structure and the position of DPY30 remain ambiguous. We used an integrated approach combining cryoelectron microscopy (cryo-EM) and mass spectrometry cross-linking to determine a structure of the MLL1-WRAD complex bound to ubiquitinated nucleosomes. The resulting model contains the Ash2L intrinsically disordered region (IDR), SPRY insertion region, Sdc1-DPY30 interacting region (SDI-motif), and the DPY30 dimer. We also resolved three additional states of MLL1-WRAD lacking one or more subunits, which may reflect different steps in the assembly of MLL1-WRAD. The docking of subunits in all four states differs from structures of MLL1-WRAD bound to unmodified nucleosomes, suggesting that H2B-ubiquitin favors assembly of the active complex. Our results provide a more complete picture of MLL1-WRAD and the role of ubiquitin in promoting formation of the active methyltransferase complex.
Organizational Affiliation:
Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205.
