| Aspect | Key claim | Evidence type | Key quantitative/statistical details | Primary source with publication date and URL/DOI | Citation id(s) to use in final answer |
|---|---|---|---|---|---|
| Identity/domains | Human ANKFY1 corresponds to Rabankyrin-5, a Rab5 effector with an N-terminal BTB/POZ domain, ~21 ankyrin repeats, and a C-terminal FYVE finger/domain. | Biochemical, cell biology | Predicted size ~130 kDa; truncation mapping used constructs spanning aa 1–1169, 1–1075, 255–1169, 255–1075. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000003, pqac-00000005, pqac-00000014) |
| Lipid binding | ANKFY1 directly binds phosphatidylinositol 3-phosphate [PI(3)P], and FYVE-mediated PI(3)P recognition is required for membrane targeting. | Biochemical | Liposome-binding assays showed strongest binding to PI(3)P; FYVE deletion abolished endosomal recruitment despite retained Rab5-GTP binding in vitro. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000003, pqac-00000006, pqac-00000014) |
| Rab5 binding | ANKFY1 binds Rab5 specifically, directly, and in a GTP-dependent manner, consistent with its designation as a Rab5 effector. | Biochemical | Binds GST-Rab5-GTPγS/GTPcS, not Rab5-GDP or other tested Rabs. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000003, pqac-00000005, pqac-00000007) |
| Localization | ANKFY1 localizes to Rab5/EEA1-positive early endosomes and to large vacuolar macropinosomes; in kidney it is enriched beneath the apical brush border of proximal tubule cells. | Cell biology | ~80% colocalization with Rab5/EEA1-positive early endosomes in A431 cells; macropinocytic structures are largely transferrin-negative. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000001, pqac-00000003, pqac-00000004, pqac-00000007) |
| Endocytosis/macropinocytosis | ANKFY1 promotes fluid-phase uptake and macropinocytosis, especially at the apical membrane of polarized epithelial cells. Overexpression increases, and depletion reduces, macropinosome formation/uptake. | Cell biology | Overexpression increased macropinosome number and fluid-phase uptake; downregulation inhibited these processes; apical restriction emphasized in polarized epithelia. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000001, pqac-00000007, pqac-00000008) |
| Endosome fusion | ANKFY1 modulates early endosome fusion, stimulating homotypic early-endosome fusion and heterotypic fusion with clathrin-coated vesicles, but appears modulatory rather than the sole essential factor. | Biochemical, cell biology | Quantitative immunodepletion produced only minor effects in some early-endosome fusion assays, supporting a modulatory role. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000003, pqac-00000006, pqac-00000014) |
| Domain requirements for targeting | Efficient recruitment of ANKFY1 to early endosomes requires both PI(3)P/FYVE recognition and Rab5 interaction; neither module alone is sufficient. | Biochemical, cell biology | FYVE deletion mutant still bound Rab5-GTP in vitro but failed to localize in vivo; recruitment assays showed dependence on both Rab5 and PI(3)P. | Schnatwinkel et al., **2004-08**, *PLoS Biology*; https://doi.org/10.1371/journal.pbio.0020261 | (pqac-00000004, pqac-00000006, pqac-00000014) |
| Autophagy/phagophore expansion | A 2024 study identified ANKFY1 as an ATG2A-binding endosomal factor that bridges endosomes and phagophores, promoting ATG2A-mediated lipid transfer for phagophore growth. | Biochemical, cell biology | ANKFY1 depletion impaired autophagosome growth and autophagy flux, largely phenocopying ATG2A/B depletion. | Wei et al., **2024-04**, *Cell Discovery*; https://doi.org/10.1038/s41421-024-00659-y | (pqac-00000009, pqac-00000010) |
| Autophagy quantitative reconstitution | In reconstituted liposome assays, ANKFY1 enhanced ATG2A-mediated lipid transfer and tethering of PI(3)P-containing liposomes; FYVE-mediated PI(3)P binding was essential. | Biochemical | Example donor liposomes: 61% DOPC, 30% POPE, 2% NBD-PE, 2% Rhod-PE, 5% PI3P; acceptor liposomes: 65% DOPC, 30% POPE, 5% PI3P; ANKFY1 roughly doubled ATG2A lipid transfer efficiency; DLS showed clustering/tethering of 100 nm PI(3)P liposomes only with ATG2A+ANKFY1; microscopy quantification used n=36 vs 48 cells in one assay and n=30 cells in others. | Wei et al., **2024-04**, *Cell Discovery*; https://doi.org/10.1038/s41421-024-00659-y | (pqac-00000010, pqac-00000011, pqac-00000012, pqac-00000017) |
| Visual/mechanistic support | Figure-level evidence shows ANKFY1-ATG2A proximity at Rab5-positive endosomes and LC3-positive phagophores, plus FRET/co-flotation support for ANKFY1-assisted ATG2A lipid transfer. | Figure/image evidence | Retrieved figures include microscopy with white-arrow-marked three-way proximity and FRET curves/quantification demonstrating enhanced transfer in the presence of ANKFY1. | Wei et al., **2024-04**, *Cell Discovery*; https://doi.org/10.1038/s41421-024-00659-y | (pqac-00000017, pqac-00000018, pqac-00000019, pqac-00000020) |
| Kidney/podocyte relevance | In podocytes, ANKFY1 localizes to Rab5-positive vesicles/endosomes in a FYVE-dependent manner and interacts with GAPVD1; this supports a role in endocytic regulation relevant to glomerular filtration barrier biology. | Cell biology, genetics | Deletion of the FYVE domain abrogated vesicular localization; ANKFY1 and GAPVD1 partially colocalized and co-immunoprecipitated; endogenous/overexpressed ANKFY1 partially colocalized with Rab5. | Hermle et al., **2018-06**, *JASN*; https://doi.org/10.1681/ASN.2017121312 | (pqac-00000002) |
| Human genetics/disease links | Biallelic ANKFY1 variants are linked to steroid-resistant nephrotic syndrome (SRNS), and a 2024 case report extends the phenotype to a probable neuro-renal syndrome with infantile-onset proteinuria plus movement disorder. | Human genetics, functional assay | 2018 study screened 665 patients by exome sequencing and found homozygous ANKFY1 missense mutation in two siblings with SRNS; 2024 case reported compound heterozygous variants p.Ser918Ter and c.3287–11_3287–10del with abnormal splicing producing 199 bp full-length and 108 bp exon-24-skipped PCR products; urinary markers included α1-microglobulin 127 mg/L, microalbumin 159 mg/L, IgG 42.3 mg/L. | Hermle et al., **2018-06**, *JASN*; https://doi.org/10.1681/ASN.2017121312; Zhang et al., **2024-06**, *Clinical Kidney Journal*; https://doi.org/10.1093/ckj/sfae124 | (pqac-00000002, pqac-00000013, pqac-00000015, pqac-00000016) |
| Variant functional consequences | Patient-derived ANKFY1 variants in the 2024 case reduced ANKFY1 protein expression but did not obviously alter subcellular localization in the overexpression assay. | Genetics, cell biology | Exon 24-skipped transcript detected; two transcripts differed by ~108 bp; western blot showed reduced ANKFY1 expression from both variants. | Zhang et al., **2024-06**, *Clinical Kidney Journal*; https://doi.org/10.1093/ckj/sfae124 | (pqac-00000013, pqac-00000015) |
| Disease-target associations | Open Targets currently lists ANKFY1 associations with familial idiopathic SRNS, neurodegenerative disease, type 2 diabetes mellitus, obesity, and overnutrition, but these are association-level signals rather than validated therapeutic indications. | Database | Evidence size reported as 3 for each listed disease; strongest score among displayed entries was for familial idiopathic SRNS (score 0.3696), followed by neurodegenerative disease (0.3345) and type 2 diabetes mellitus (0.2181). | Open Targets platform query for ANKFY1, accessed during this research; https://platform.opentargets.org/ | (pqac-00000000) |


*Table: This table summarizes the main experimentally supported functions, localization, pathways, and disease links for human ANKFY1/Rabankyrin-5. It is designed to provide citable claims and quantitative details for a final research report.*