RNF40
Function
Component of the RNF20/40 E3 ubiquitin-protein ligase complex that mediates monoubiquitination of 'Lys-120' of histone H2B (H2BK120ub1). H2BK120ub1 gives a specific tag for epigenetic transcriptional activation and is also prerequisite for histone H3 'Lys-4' and 'Lys-79' methylation (H3K4me and H3K79me, respectively). It thereby plays a central role in histone code and gene regulation. The RNF20/40 complex forms a H2B ubiquitin ligase complex in cooperation with the E2 enzyme UBE2A or UBE2B; reports about the cooperation with UBE2E1/UBCH are contradictory. Required for transcriptional activation of Hox genes.
(Microbial infection) Promotes the human herpesvirus 8 (KSHV) lytic cycle by inducing the expression of lytic viral genes including the latency switch gene RTA/ORF50.
Pathway
Protein modification; protein ubiquitination.
Sequence Similarities
Belongs to the BRE1 family.
Tissue Specificity
Ubiquitously expressed. Expressed at higher level in testis, heart and pancreas, while it is only weakly expressed in lung, skeletal muscle and small intestine.
Cellular localization
- Nucleus
Alternative names
BRE1B, KIAA0661, RNF40, E3 ubiquitin-protein ligase BRE1B, BRE1-B, 95 kDa retinoblastoma-associated protein, RING finger protein 40, RING-type E3 ubiquitin transferase BRE1B, RBP95