Ubiquitin activating enzyme

Function

Ubiquitin activating enzyme (Uba) or E1 enzyme catalyzes the first step in the ubiquitination of a protein tagged to be degraded by the proteasome. Ubiquitin activating enzyme (E1) and ATP produce a C-terminal acyl adenylated ubiquitin molecule which binds to ubiquitin conjugating enzyme (E2) (Ubc) cysteine^[1]. The Ubc then binds to ubiquitin ligase (E3) via a conserved binding region. E3 catalyzes the transfer of ubiquitin from the Ubc-ubiquitin complex to a lysine residue of the target protein.

• Uba1 see Uba1.
  
• Uba3 is the catalytic subunit of NEDD8 activating enzyme and APPB1 is its regulatory subunit. Similar to ubiquitin and SUMO, NEDD8 binds to proteins after processing of its C-terminal.
  
• Uba6 regulates the interferon-gamma production of T-cells by modulating NF-κB activation pathway^[2].

For ubiquitin-like modifier-activating enzyme Atg7 see Autophagy-related protein

(PDB entry 1y8x). .

3D structures of Ubiquitin activating enzyme

References

1. ↑ Nagai Y, Kaneda S, Nomura K, Yasuda H, Seno T, Yamao F. Ubiquitin-activating enzyme, E1, is phosphorylated in mammalian cells by the protein kinase Cdc2. J Cell Sci. 1995 Jun;108 ( Pt 6):2145-52. PMID:7673335
2. ↑ Lee JY, An EK, Hwang J, Jin JO, Lee PCW. Ubiquitin Activating Enzyme UBA6 Regulates Th1 and Tc1 Cell Differentiation. Cells. 2021 Dec 29;11(1):105. PMID:35011668 doi:10.3390/cells11010105