UPF3B

UniProt: Q9BZI7 · batch: proteostasis-batch-2026-06-07c · review status: COMPLETE
PN placement: Translation|Cytosolic translation|Translation termination|Modulation of termination ; PN-node mapping: type no_mapping; group mapped, ok_for_propagation → GO:0006415 translational termination; class/branch context_only, too_broad. Projected: GO:0006415 (goa_status=new_to_goa).
Consistency: Gene-level consistent. Deep-research/notes, review YAML and GOA agree UPF3B is the principal active UPF3 paralog: EJC-associated NMD adaptor that recruits UPF2 and links to UPF1, stimulating NMD. Core: GO:0003729 mRNA binding, GO:0035145 EJC, GO:0170010 NMD complex, GO:0000184 NMD (ACCEPT, multiple), and notably GO:2000624 positive regulation of NMD — the correct opposite directionality to its antagonist paralog UPF3A. No internal contradictions; the UPF3A/UPF3B directionality is handled correctly across the pair.
PN story / NEW pressure: PN groups UPF3B under "Modulation of termination," projecting GO:0006415 as new_to_goa. UPF3B's biology (positive NMD adaptor) is fully captured by GO:0000184 + GO:2000624 + EJC/complex terms. No NEW term is defensible; the termination link is indirect (acts after termination, via the surveillance complex).
Mapping strategy: As with the other UPF genes, GROUP→GO:0006415 (translational termination, = peptide release) over-reaches — UPF3B is an EJC/NMD adaptor, not a release factor — and would be an unsupported new GOA assertion. Type-level no_mapping should govern; UPF3B is already correctly anchored on GO:0000184 and positively-directed GO:2000624.
Evidence alignment: PN row carries no reference titles; review well-evidenced (PMID:18066079 UPF2/UPF3 bridge UPF1 / stimulate helicase; UniProt EJC-link FUNCTION; NMD/complex terms). No competing PN citations.
Verdict: Consistent gene biology with correct positive directionality (mirror of UPF3A); PN group→GO:0006415 over-reaches — UPF3B's role is NMD adaptor (GO:0000184 / GO:2000624), not translational termination.

Recommended edits: [MAP] do NOT project GO:0006415 (translational termination) onto UPF3B — it is an EJC/NMD adaptor acting downstream of termination, already correctly anchored on GO:0000184 and GO:2000624 (positive regulation of NMD). Type-level no_mapping should win.