The minimal, reusable ubiquitin-conjugation relay: an E1 ubiquitin-activating enzyme adenylates ubiquitin and forms a thioester with it in an ATP-dependent reaction; the activated ubiquitin is passed to the active-site cysteine of an E2 conjugating enzyme; and an E3 ligase brings the E2~ubiquitin together with a selected substrate to transfer ubiquitin onto a substrate lysine. Iteration builds polyubiquitin chains that mark substrates for proteasomal degradation or other fates. The same relay (with cognate activating/conjugating/ligase enzymes) is reused by the ubiquitin-like modifiers SUMO, NEDD8, and ISG15. The motif is gene-free and taxon-neutral, fixing only the E1/E2/E3 roles by molecular-function term and the activating transfer topology. Grounded in GO:0016567 (protein ubiquitination).
Reusable conformance target. A node declares `conforms_to: [{template: ubiquitin_transfer_relay}]` when its steps instantiate the E1-activation / E2-conjugation / E3-ligation transfer. The E3 architecture (RING, HECT, RBR; monomeric or cullin-RING/SCF) and the modifier identity (ubiquitin vs SUMO/NEDD8) are realization-specific.
All recommended fields populated.
✗ none found
No MODULE:ubiquitin_transfer_relay deep-research report alongside the module YAML.
3 leaf node(s) with no concrete protein grounding:
✓ every declared conforms_to bundle matches its template motif.
No concrete UniProt-grounded genes in this module.
The E1 enzyme adenylates ubiquitin and forms an E1~ubiquitin thioester (ATP-dependent).
Activates ubiquitin and charges the E2.
The activated ubiquitin is transferred to the active-site cysteine of an E2 conjugating enzyme.
Carries activated ubiquitin to the E3.
The E3 ligase positions the E2~ubiquitin and a selected substrate to transfer ubiquitin onto a substrate lysine.
Transfers ubiquitin onto the selected substrate.