NIRF is a ubiquitin ligase that is capable of ubiquitinating PCNP, a PEST-containing nuclear protein

FEBS Lett. 2004 Jan 16;557(1-3):209-14. doi: 10.1016/s0014-5793(03)01495-9.


We previously reported the association of a novel Np95/ICBP90-like RING finger protein (NIRF) with a novel PEST-containing nuclear protein (PCNP). NIRF is a nuclear protein with a ubiquitin-like domain, a PHD finger, a YDG/SRA domain, Rb-binding motifs and a RING finger. In this study, we showed that NIRF has auto-ubiquitination activity, the hallmark of a ubiquitin ligase. PCNP was readily ubiquitinated in 293 and COS-7 cells, and NIRF ubiquitinated PCNP in vitro as well as in vivo. Considering that NIRF is implicated in cell cycle regulation, these findings suggest that NIRF and PCNP are a ubiquitin ligase and its substrate, respectively, and may constitute a novel signaling pathway with some relation to cell proliferation.

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • COS Cells
  • Catalysis
  • Cell Line
  • Chlorocebus aethiops
  • Humans
  • Kinetics
  • Molecular Sequence Data
  • Nuclear Proteins / metabolism*
  • Rabbits
  • Transfection
  • Ubiquitin / metabolism
  • Ubiquitin-Protein Ligases / metabolism*


  • Adaptor Proteins, Signal Transducing
  • Nuclear Proteins
  • PCNP protein, human
  • Ubiquitin
  • UHRF2 protein, human
  • Ubiquitin-Protein Ligases

Associated data

  • GENBANK/AB037675
  • GENBANK/AB071698