RanBP-type & C3HC4-type zinc finger-containing protein 1; ubiquitin-conjugating enzyme 7-interacting protein 3; hepatitis B virus X-associated protein 4; HBV-associated factor 4; heme-oxidized IRP2 ubiquitin ligase 1; RING finger protein 54 (RBCK1, C20orf18, RNF54, UBCE7IP3, XAP3, XAP4)

Function

• might act as an E3 ubiquitin-protein ligase, or as part of the E3 complex, which accepts ubiquitin from specific E2 ubiquitin-conjugating enzymes, such as UBE2L3/UBCM4, & then transfers it to substrates
• functions as an E3 ligase for oxidized IREB2 & both heme & oxygen are necessary for IREB2 ubiquitination
• interacts with protein kinase C beta-1-type (PRKCB1) & protein kinase C zeta-type (PRKCZ) & with UBE2L3
• forms homodimers in vitro
• interacts with PRKCH
• interacts with the HBV pX/HBx protein, which is required to activate transcription of the viral genome
• isoform 1 & isoform 2 interact with IREB2 only in iron-rich conditions

Structure

• contains 1 B box-type Zn+2 finger
• contains 1 RanBP2-type Zn+2 finger
• contains 1 RING-type Zn+2 finger
• contains 1 ubiquitin-like domain

Alternative splicing

• named isoforms=3
• some isoforms may be produced at very low levels due to a premature stop codon in the mRNA, leading to nonsense-mediated mRNA decay

More general terms

• ubiquitin conjugating enzyme 7 interacting protein
• ring finger protein
• phosphoprotein

Additional terms

• hepatitis B virus (HBV)
• ubiquitin (UBCEP2, UBB, UBC)

Database

• Entrez gene: http://www.ncbi.nlm.nih.gov/sites/entrez?db=gene&cmd=Retrieve&dopt=Graphics&list_uids=10616
• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:10616
• OMIM: https://mirror.omim.org/entry/610924
• UniProt: http://www.uniprot.org/uniprot/Q9BYM8.html