Molecular basis for the recognition of CIZ1 by ERH

FEBS J. 2023 Feb;290(3):712-723. doi: 10.1111/febs.16611. Epub 2022 Sep 11.

Abstract

Enhancer of rudimentary homologue (ERH), a small protein conserved in eukaryotes, is involved in a wide spectrum of cellular events, including cell cycle progression, piRNA biogenesis, miRNA maturation and gene expression. Human ERH is recruited to replication foci by CDKN1A-interacting zinc finger protein 1 (CIZ1), and plays an important role in cell growth control. However, the molecular basis for CIZ1 recognition by ERH remains unknown. By using GST pull-down experiment, we found that a fragment within CIZ1, upstream of its first zinc finger, is sufficient for binding to ERH. We solved the structure of CIZ1-bound ERH, in which the ERH dimer binds to two CIZ1 fragments to form a 2 : 2 heterotetramer. CIZ1 forms intermolecular antiparallel β-strands with ERH, and its binding surface on ERH is distinct from those of other known ERH-binding ligands. The ERH-CIZ1 interface was further validated by mutagenesis and binding experiments. Our structural study complemented by biochemistry experiments not only provides insights into a previously unidentified ligand-binding mode for ERH but also sheds light on the understanding of evolutionarily conserved roles for ERH orthologs.

Keywords: CDKN1A-interacting zinc finger protein 1; crystal structure; enhancer of rudimentary homologue; homodimer; replication foci.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Cycle
  • Cell Cycle Proteins* / genetics
  • Cell Division
  • Genes, cdc
  • Humans
  • Nuclear Proteins / metabolism
  • Transcription Factors* / genetics

Substances

  • Transcription Factors
  • Cell Cycle Proteins
  • Ciz1 protein, human
  • Nuclear Proteins