| Study | Year/Month | Publication type | Key finding for ENDOU function | Enzymatic details (substrate/cofactor/products) | Localization/expression | Application/disease context | URL/DOI |
|---|---|---|---|---|---|---|---|
| Laneve et al., *J. Biol. Chem.* | 2008/Dec | Primary research | Human ENDOU/PP11 was experimentally reclassified from a putative protease to an endoribonuclease in the XendoU/EndoU family; mutagenesis supported a catalytic center involving H244, E243, E249, H259, and K302 (pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000004, pqac-00000007) | Binds RNA and cleaves single-stranded RNA at uridylates in a Mn²⁺-dependent reaction, yielding 2′,3′-cyclic phosphate ends; cleavage preference reported around GU, UA, AU, CU, UU, and UC motifs (pqac-00000001, pqac-00000002, pqac-00000003, pqac-00000004) | High placental expression, especially syncytiotrophoblast; prior work cited in the paper reported exclusive cytoplasmic localization in syncytiotrophoblast; precursor (~45 kDa) and mature (~42 kDa) forms were described (pqac-00000001, pqac-00000007, pqac-00000014, pqac-00000015, pqac-00000016) | Tumor-marker context: reported in 66.7% of mucinous cystadenocarcinomas, 57.1% of serous cystadenocarcinomas, 47% of breast cancers, and 38% of testicular/gastric cancers; authors also proposed a possible placental antiviral role (pqac-00000001, pqac-00000006, pqac-00000014) | https://doi.org/10.1074/jbc.m805759200 |
| Mushegian et al., *RNA* | 2020/Apr | Evolutionary/computational primary research | Positioned EndoU-family ribonucleases, including human ENDOU, within an ancient evolutionary relationship to the RNase A-like superfamily, supporting ENDOU as part of a deeply conserved RNase lineage rather than an isolated placental protein class (pqac-00000000) | Evolution/structure focused; no new human biochemical assay details extracted here beyond EndoU-family catalytic-domain homology (pqac-00000000) | Family-level context across bacteria, archaea, eukaryotes, and viruses; not a human localization study (pqac-00000000) | Useful for functional inference and domain-based annotation of human ENDOU (pqac-00000000) | https://doi.org/10.1261/rna.074385.119 |
| Nomoto et al., *J. Clin. Biochem. Nutr.* | 2021/Jul | Primary research | Proteomics identified ENDOU as significantly upregulated in cytotrophoblasts from placentas with preeclampsia/fetal growth restriction (PE-FGR), reinforcing relevance in placental biology (pqac-00000008, pqac-00000012) | Described, citing prior biochemical work, as a poly(U)-specific/uridylate-cleaving endoribonuclease acting on single-stranded RNA in an Mn²⁺-dependent manner; no new catalytic chemistry defined in this study (pqac-00000008) | Increased ENDOU protein expression in PE-FGR cytotrophoblasts versus controls (pqac-00000008, pqac-00000012) | Pregnancy disease/placental pathology biomarker context; paper also discussed homology to coronavirus Nsp15 and possible relevance to stress/host-response pathways (pqac-00000008, pqac-00000012) | https://doi.org/10.3164/jcbn.21-37 |
| Xu et al., *Front. Oncol.* | 2021/Feb | Primary research with bioinformatics and cell assays | ENDOU emerged as an independent prognostic marker candidate in head and neck squamous cell carcinoma (HNSCC); overexpression inhibited proliferation and migration of FaDu and Cal-27 cells, consistent with a tumor-suppressive effect in that setting (pqac-00000000) | Functional cancer study; enzymatic mechanism not newly characterized, but paper identified ENDOU/PP11 as uridylate-specific endoribonuclease based on prior literature (pqac-00000000) | Reported relatively low ENDOU expression in HNSCC, especially HPV-positive samples; correlations with immune infiltrates were noted (pqac-00000000) | Prognostic biomarker and tumor-suppressor-like candidate in HNSCC (pqac-00000000) | https://doi.org/10.3389/fonc.2020.522332 |
| Bašić et al., *Oncol. Lett.* | 2021/Oct | Primary research/meta-analysis with immunohistochemistry | Integrative transcriptomic meta-analysis nominated ENDOU as a potential diagnostic biomarker in cervical squamous cell carcinoma (pqac-00000000) | No new enzymology; paper characterized ENDOU as a soluble poly(U)-specific endoribonuclease based on prior studies (pqac-00000000) | IHC showed ENDOU positivity in ~1% of tumors versus ~40% of non-tumor tissues in the analyzed cohort, consistent with reduced expression in cancer tissue (pqac-00000000) | Potential diagnostic biomarker for cervical squamous cell carcinoma; low ENDOU associated with inhibition of epithelial development/differentiation processes (pqac-00000000) | https://doi.org/10.3892/ol.2021.13101 |
| Sun et al., *Nat. Commun.* | 2023/Oct | Primary research | Drosophila Arlr was identified as an ortholog/paralog system for mammalian EndoU biology; human ENDOU rescued arlr mutant lipid-storage defects, supporting conserved ENDOU-family function in post-transcriptional control of lipid metabolism (pqac-00000009, pqac-00000011) | In the cross-species rescue experiments, human ENDOU expression restored lipid droplet size and TAG levels and reduced mRNAs of candidate lipolysis genes; study implies conserved RNase-dependent control of target mRNAs but did not provide new human biochemical reaction chemistry (pqac-00000009, pqac-00000011) | Functional rescue was achieved by transgenic human ENDOU expression in Drosophila fat body; paper notes ENDOU contains a signal peptide and EndoU domain (pqac-00000009) | Mechanistic relevance to lipid homeostasis/aging and evidence for conserved physiological roles beyond placenta (pqac-00000009, pqac-00000011) | https://doi.org/10.1038/s41467-023-42042-7 |
| Malard et al., *Nat. Commun.* | 2025/Apr | Primary structural/biophysical research | Although outside 2023–2024, this mechanistically important study showed that eukaryotic/human EndoU is activated allosterically by Ca²⁺ binding remote from the catalytic triad, linking its N-terminal extension to catalytic control (pqac-00000005, pqac-00000013) | Crystal structure and biophysical assays supported calcium-dependent activation; calcium binding triggers structural rearrangements and water-mediated signaling to the catalytic core; study builds on prior knowledge that human ENDOU cleaves ssRNA 5′ of uridylates (pqac-00000005, pqac-00000013) | Reported expression in placenta and stratified squamous epithelia; cited as a biomarker in several cancers (squamous cell carcinoma, ovarian adenocarcinoma, non-trophoblastic tumors, breast cancer) (pqac-00000005, pqac-00000013) | Mechanistic clarification of ENDOU regulation and renewed biomarker relevance; not within requested date priority window but highly informative for annotation (pqac-00000005, pqac-00000013) | https://doi.org/10.1038/s41467-025-58462-6 |


*Table: This table compiles the most relevant evidence for human ENDOU/PP11 across foundational biochemistry, placental pathology, cancer biomarker studies, evolutionary inference, and recent cross-species functional work. It emphasizes experimentally supported claims and separates mechanistic human ENDOU findings from broader EndoU-family context.*