UBE4B

The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes, or E1s, ubiquitin-conjugating enzymes, or E2s, and ubiquitin-protein ligases, or E3s. This gene encodes an additional conjugation factor, E4, which is involved in multiubiquitin chain assembly. This gene is also the strongest candidate in the neuroblastoma tumor suppressor genes. Alternatively spliced transcript variants encoding distinct isoforms have been found for this gene. [provided by RefSeq]

Full Name

ubiquitination factor E4B (UFD2 homolog, yeast)

Function

Ubiquitin-protein ligase that probably functions as an E3 ligase in conjunction with specific E1 and E2 ligases (By similarity).
May also function as an E4 ligase mediating the assembly of polyubiquitin chains on substrates ubiquitinated by another E3 ubiquitin ligase (By similarity).
May regulate myosin assembly in striated muscles together with STUB1 and VCP/p97 by targeting myosin chaperone UNC45B for proteasomal degradation (PubMed:17369820).

Biological Process

Biological Process granzyme-mediated apoptotic signaling pathway Source:UniProtKB1 Publication
Biological Process proteasome-mediated ubiquitin-dependent protein catabolic process Source:MGI1 Publication
Biological Process protein polyubiquitination Source:GO_Central1 Publication
Biological Process response to UV Source:UniProtKB1 Publication
Biological Process ubiquitin-dependent ERAD pathway Source:GO_Central1 Publication
Biological Process ubiquitin-dependent protein catabolic process Source:UniProtKB1 Publication

Cellular Location

Cytoplasm
Nucleus

PTM

Proteolytically cleaved by caspases during apoptosis. Cleaved efficiently at Asp-123 by caspase-6 and granzyme B. Cleaved with approximately 10-fold less efficiency at Asp-109 by caspase-3 and caspase-7.