Cryo-electron microscopy structure of a human PRMT5:MEP50 complex

PLoS One. 2018 Mar 8;13(3):e0193205. doi: 10.1371/journal.pone.0193205. eCollection 2018.

Abstract

Protein arginine methyl transferase 5 (PRMT5) is a signaling protein and histone modifying enzyme that is important in many cellular processes, including regulation of eukaryotic gene transcription. Reported here is a 3.7 Å structure of PRMT5, solved in complex with regulatory binding subunit MEP50 (methylosome associated protein 50, WDR77, p44), by single particle (SP) cryo-Electron Microscopy (cryo-EM) using micrographs of particles that are visibly crowded and aggregated. Despite suboptimal micrograph appearance, this cryo-EM structure is in good agreement with previously reported crystal structures of the complex, which revealed a 450 kDa hetero-octameric assembly having internal D2 symmetry. The catalytic PRMT5 subunits form a core tetramer and the MEP50 subunits are arranged peripherally in complex with the PRMT5 N-terminal domain. The cryo-EM reconstruction shows good side chain definition and shows a well-resolved peak for a bound dehydrosinefungin inhibitor molecule. These results demonstrate the applicability of cryo-EM in determining structures of human protein complexes of biomedical significance and suggests cryo-EM could be further utilized to understand PRMT5 interactions with other biologically important binding proteins and ligands.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / chemistry*
  • Adaptor Proteins, Signal Transducing / metabolism
  • Cryoelectron Microscopy*
  • Humans
  • Imaging, Three-Dimensional
  • Models, Molecular
  • Molecular Structure
  • Protein Conformation
  • Protein-Arginine N-Methyltransferases / chemistry*
  • Protein-Arginine N-Methyltransferases / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • MEP50 protein, human
  • PRMT5 protein, human
  • Protein-Arginine N-Methyltransferases

Grants and funding

This research was funded in its entirety by Eli Lilly and Company. Eli Lilly and Company provided support in the form of salaries for authors [DET, RM, CR], but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section. Disclosure of this work in the form of a published manuscript has been approved by Eli Lilly and Company.