## MKRN2
- **UniProt:** Q9H000 · **batch:** proteostasis-batch-2026-06-07c · **review status:** COMPLETE
- **PN placement:** two rows — `Translation|Cytosolic translation|Ribosome-associated QC|Ubiquitination` (TR) and `UPS|E3 ubiquitin and UBL ligases|RING|Makorin|C3H1-type ZnF` (UPS). **PN-node mapping:** identical to MKRN1 — RQC type→GO:0016567 (mapped); RQC group→GO:0006515 (mapped); RING group→GO:0061630 (mapped); subtype + UPS branch = no_mapping.
- **Consistency:** Partial mismatch. The UPS/E3-ligase placement (GO:0061630, GO:0016567) matches the review perfectly — both already in GOA (IBA/IEA/ISS). BUT the PN puts MKRN2 in the **same RQC node as MKRN1**, projecting GO:0006515 (protein QC). The review finds **no direct or inferred RQC evidence for human MKRN2** — RQC is raised only as a *suggested question* ("does MKRN2 contribute to co-translational QC… how is it partitioned from MKRN1?"). MKRN2's characterized biology is RELA/p65 / NF-kB (mostly ISS/by-similarity from rodent), not poly(A) RQC. So the PN RQC placement for MKRN2 is **paralogy-driven over-reach**, inherited from MKRN1.
- **PN story / NEW pressure:** No defensible NEW pressure. There is no human-experimental basis to annotate MKRN2 to GO:0006515 or GO:1990116; doing so would be PARALOG_OVERANNOTATION (MKRN1 evidence applied to MKRN2). The review correctly withholds an RQC annotation. The genuine MKRN2 functions (E3 ligase, NF-kB regulation) are already captured/over-annotation-flagged.
- **Mapping strategy:** This gene should NOT inherit the RQC-group GO:0006515 projection. The node mapping is fine as a *bucket* for MKRN1, but MKRN2's membership in that node is the problem — its projected GO:0006515 is unsupported for this paralog. Flag: MKRN2 RQC placement is broader/unsupported relative to the review (which has zero RQC terms).
- **Evidence alignment:** PN row 2 cites "19489725 / rev" (makorin review, same as MKRN1). Review anchors only on RNA-binding screen PMID:22681889 (HDA, VERIFIED) plus uniprot/ISS; notably **no dedicated experimental paper establishes human MKRN2's E3 activity or any RQC role** — consistent with the review's caution. Divergence: PN asserts RQC; review evidence does not.
- **Verdict:** Over-reach on the RQC branch (paralog inheritance from MKRN1). E3-ligase placement consistent. **Recommended edits:** [MAP] do not project GO:0006515 / GO:1990116 onto MKRN2 from the RQC node — no human-experimental RQC evidence; flag MKRN2's RQC-node membership as paralogy-driven (PARALOG_OVERANNOTATION) pending the suggested iCLIP/ribosome-profiling experiment.