id: ARBA00089175 description: 'This rule predicts GO:1990849 (vacuolar localization) for eukaryotic proteins containing two specific CATH FunFam domains: 1.20.58.900:FF:000013 and 2.30.29.30:FF:000315, both associated with pleckstrin homology domain-containing family M member 1 (PLEKHM1). The rule targets the eukaryotic domain (NCBITaxon:2759).' status: COMPLETE rule_type: ARBA rule: rule_id: ARBA00089175 condition_sets: - number: 1 conditions: - condition_type: FUNFAM value: 1.20.58.900:FF:000013 curie: CATH.FunFam:1.20.58.900:FF:000013 label: pleckstrin homology domain-containing family M member 1 isoform X1 negated: false - condition_type: FUNFAM value: 2.30.29.30:FF:000315 curie: CATH.FunFam:2.30.29.30:FF:000315 label: pleckstrin homology domain-containing family M member 1 isoform X1 negated: false - condition_type: TAXON value: '2759' curie: NCBITaxon:2759 label: Eukaryota negated: false notes: This condition set requires both FunFam domains that are characteristic of PLEKHM1 proteins. The analysis shows these two domains are completely redundant (Jaccard similarity 1.0), both co-occurring in exactly 3 proteins in SwissProt. The domains are completely contained within the set of proteins annotated with GO:1990849 (containment 1.0), suggesting this is a highly specific but narrow rule. pairwise_overlap: - condition_a: 1.20.58.900:FF:000013 condition_b: 2.30.29.30:FF:000315 protein_database: SWISSPROT count_a: 3 count_b: 3 intersection_count: 3 a_minus_b_count: 0 b_minus_a_count: 0 jaccard_similarity: 1.0 containment_a_in_b: 1.0 containment_b_in_a: 1.0 interpretation: REDUNDANT go_annotations: - go_id: GO:1990849 go_label: vacuolar localization aspect: BP entries: - id: 1.20.58.900:FF:000013 type: FUNFAM label: pleckstrin homology domain-containing family M member 1 isoform X1 appears_in_condition_sets: - 1 protein_count: 3 related_entries: - relationship: EQUIV target_id: 2.30.29.30:FF:000315 containment: 1.0 jaccard_similarity: 1.0 intersection_count: 3 exclusive_count: 0 - relationship: PREDICTS target_id: GO:1990849 containment: 1.0 jaccard_similarity: 0.01 intersection_count: 3 exclusive_count: 0 - id: 2.30.29.30:FF:000315 type: FUNFAM label: pleckstrin homology domain-containing family M member 1 isoform X1 appears_in_condition_sets: - 1 protein_count: 3 related_entries: - relationship: EQUIV target_id: 1.20.58.900:FF:000013 containment: 1.0 jaccard_similarity: 1.0 intersection_count: 3 exclusive_count: 0 - relationship: PREDICTS target_id: GO:1990849 containment: 1.0 jaccard_similarity: 0.01 intersection_count: 3 exclusive_count: 0 review_summary: ARBA00089175 targets a very specific set of proteins (PLEKHM1 family) for vacuolar localization annotation. The rule shows complete domain redundancy between its two FunFam conditions, which both identify the same 3 SwissProt proteins. While the biological basis appears sound (PLEKHM1 proteins are known to localize to lysosomes/vacuoles), the rule design is overly complex given the complete overlap of the two domains. The taxonomic restriction to Eukaryota is appropriate. Deep research is needed to validate whether GO:1990849 (a biological process term for vacuolar localization/transport) is the most appropriate term versus a cellular component term for vacuolar membrane or lumen localization. action: ACCEPT action_rationale: The rule has a strong biological basis with extensive experimental support for PLEKHM1's role in actively regulating lysosomal/vacuolar positioning. The BP term GO:1990849 is appropriate because PLEKHM1 participates in the process of localizing vacuoles/lysosomes rather than merely being a resident protein. Evidence from multiple systems (mammalian cells, osteoclasts, yeast orthologs) demonstrates conserved function in endolysosomal positioning through Rab7/Arl8b dual effector activity. While the two FunFam domains show complete statistical overlap, both RUN and PH domains may be necessary for PLEKHM1's characteristic multi-domain architecture. The rule is highly specific (only 3 proteins in SwissProt) and appears to correctly capture the PLEKHM1 family. Minor considerations include whether mammalian proteins should use "lysosome localization" instead of the generic "vacuolar" term, but this is acceptable for cross-eukaryotic application. suggested_modifications: - Consider adding complementary GO annotations capturing PLEKHM1's other functions such as "autophagosome-lysosome fusion" (GO:0097352), "SNARE complex assembly", or "vesicle tethering" for a more comprehensive functional description - For mammalian-specific annotations, consider using "lysosome localization" (GO:0032418) as a more precise alternative to generic "vacuolar localization" - Verify whether the two FunFam conditions represent functionally distinct domains (RUN vs PH) or merely alternative CATH classifications of the same protein; if the latter, one could be removed for parsimony parsimony: assessment: ACCEPTABLE notes: 'The rule requires both RUN domain (1.20.58.900:FF:000013) and PH domain (2.30.29.30:FF:000315) FunFams, which show complete co-occurrence in SwissProt (Jaccard 1.0). While this appears redundant statistically, it may be biologically justified. PLEKHM1 function requires the integration of both domains: the RUN domain mediates Arl8b binding and is necessary for lysosomal localization, while the PH domain likely contributes to membrane association. The combination of RUN and PH domains may be diagnostic for PLEKHM1-like proteins performing dual-GTPase effector functions. However, if these FunFams represent different structural classifications of the same protein regions rather than functionally distinct domains, then one condition could potentially be removed.' supported_by: - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml supporting_text: '"condition_a: 1.20.58.900:FF:000013, condition_b: 2.30.29.30:FF:000315, protein_database: SWISSPROT, count_a: 3, count_b: 3, intersection_count: 3, a_minus_b_count: 0, b_minus_a_count: 0, jaccard_similarity: 1.0, containment_a_in_b: 1.0, containment_b_in_a: 1.0, interpretation: REDUNDANT"' - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md supporting_text: '"PLEKHM1 architecture and core biology: Reviews and recent primary work describe PLEKHM1 (pleckstrin homology and RUN domain-containing M1) as a multivalent adaptor: an N‑terminal PH domain, central RUN domain(s), a C‑terminal Rubicon-homology (RH) region that binds Rab7, and a canonical LC3‑interacting region (LIR)."' literature_support: assessment: STRONG notes: 'Extensive experimental evidence supports PLEKHM1''s role in lysosomal/vacuolar localization and positioning. PLEKHM1 functions as a dual Rab7/Arl8b effector that localizes to late endosomes and lysosomes, recruiting HOPS complex components and mediating membrane tethering and fusion. Multiple lines of evidence demonstrate that PLEKHM1 actively regulates lysosomal positioning: immunofluorescence shows colocalization with LAMP1, depletion causes abnormal perinuclear lysosome clustering, and osteoclast-specific knockout impairs lysosome trafficking to the ruffled border. The RUN domain mediates Arl8b binding while the RH domain binds Rab7, allowing PLEKHM1 to coordinate opposing motor-based transport systems. Human disease mutations causing osteopetrosis further validate the biological importance of PLEKHM1''s vacuolar localization function.' supported_by: - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"Immunofluorescence microscopy studies using specific anti-PLEKHM1 antibodies demonstrate robust colocalization of PLEKHM1 with LAMP1, a canonical lysosomal marker protein. Furthermore, structured illumination microscopy and cryo-immunogold electron microscopy reveal that PLEKHM1 localizes specifically to the limiting membranes of enlarged and tightly clustered endolysosomal compartments."' - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"By simultaneously binding both Rab7 (which promotes minus-end-directed dynein-mediated transport through RILP) and Arl8b (which promotes plus-end-directed kinesin-mediated transport through SKIP), PLEKHM1 effectively coordinates the balance between competing motor systems."' - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md supporting_text: '"PLEKHM1 acts as a multivalent adaptor that binds Rab7, Arl8, LC3/GABARAPs, and HOPS; contains a canonical LIR that docks into LC3B; RUN–HOPS contacts are proposed but need more structural work. Autophagosome–lysosome fusion is a central role."' - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"Loss-of-function mutations in PLEKHM1 result in autosomal recessive osteopetrosis type 6 (OPTB6), a human genetic disorder characterized by increased bone density reflecting impaired osteoclast function. The molecular basis for osteopetrosis in PLEKHM1-deficient patients derives from the inability of osteoclasts to properly position lysosomes at the ruffled border."' condition_overlap: assessment: COMPLETE notes: The two FunFam conditions show complete overlap, both matching exactly the same 3 proteins in SwissProt. This represents maximal redundancy where one condition provides no additional discriminatory power beyond the other. Standard curation practice would be to retain only one condition. supported_by: - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml supporting_text: '"Analyzed 1 domain-domain pairs and 2 domain-GO pairs across entire rule. Average Jaccard similarity: 0.340. 1 pairs with >50% overlap, 2 subset relationships."' go_specificity: assessment: APPROPRIATE notes: 'GO:1990849 "vacuolar localization" is appropriate for PLEKHM1 proteins, as they actively regulate lysosomal/vacuolar positioning rather than merely being resident proteins. PLEKHM1 coordinates opposing motor-based transport systems through dual Rab7/Arl8b binding, with overexpression causing dramatic perinuclear clustering and depletion causing loss of peripheral distribution. The term captures PLEKHM1''s role in the process of localizing vacuoles/lysosomes to specific cellular locations. However, there is a taxonomic terminology consideration: in mammals the organelle is properly called "lysosome" while in yeast/fungi it is "vacuole". The generic term "vacuolar localization" may be appropriately broad for cross-eukaryotic application, though mammalian-specific annotations might prefer "lysosome localization" (GO:0032418).' supported_by: - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"Overexpression of PLEKHM1 together with Arl8b results in dramatic perinuclear clustering of lysosomes, whereas Arl8b expression alone promotes peripheral lysosomal positioning. These positioning effects reflect genuine changes in lysosomal localization patterns rather than artifacts of overexpression."' - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"The distinction between vacuolar localization and protein localization to the vacuole proves critical for accurate rule implementation. Vacuolar localization describes organellar transport and positioning processes, while protein localization to vacuole (GO:0072665) would describe the process by which individual protein molecules become associated with vacuolar membranes."' taxonomic_scope: assessment: APPROPRIATE notes: The rule restricts to Eukaryota (NCBITaxon:2759), which is appropriate since vacuoles/lysosomes are eukaryote-specific organelles. PLEKHM1 orthologs exist throughout eukaryotic lineages and maintain conserved interactions with Rab GTPases and HOPS complex components. The core mechanism appears ancient, with conservation across fungal, plant, and animal kingdoms. Yeast possess functional homologs of mammalian PLEKHM1, and heterologous expression studies demonstrate functional conservation. However, some functional divergence may exist between unicellular and multicellular eukaryotes, particularly regarding vacuole organization and cell cycle-linked pH dynamics in yeast versus mammalian lysosomes. supported_by: - reference_id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md supporting_text: '"Comparative genomics and functional studies indicate that PLEKHM1 orthologs exist throughout eukaryotic lineages and maintain conserved interactions with Rab GTPases and HOPS complex components. Yeast possesses functional homologs of mammalian PLEKHM1, as demonstrated by studies showing that deletion of yeast vacuolar protein sorting genes results in autophagy and endocytic trafficking defects similar to those observed in mammalian cells lacking PLEKHM1."' confidence: 0.8 references: - id: file:rules/arba/ARBA00089175/ARBA00089175-analysis.yaml title: Domain overlap analysis for ARBA00089175 findings: - statement: Two FunFam conditions show complete redundancy with Jaccard similarity 1.0 - statement: Both domains match exactly 3 proteins in SwissProt - statement: Both domains are completely contained within GO:1990849 annotated proteins - id: file:rules/arba/ARBA00089175/ARBA00089175.enriched.json title: Enriched rule data for ARBA00089175 findings: - statement: Rule created 2025-03-21, predicts GO:1990849 for Eukaryota - statement: Uses two CATH FunFam conditions for PLEKHM1 isoform X1 - id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-perplexity.md title: Deep research analysis of PLEKHM1 vacuolar localization (Perplexity) findings: - statement: PLEKHM1 localizes to late endosomes/lysosomes through Rab7 and Arl8b interactions - statement: Functions as dual GTPase effector coordinating opposing motor-based transport systems - statement: Recruits HOPS tethering complex to mediate autophagosome-lysosome fusion - statement: Loss causes osteopetrosis in humans due to impaired lysosome trafficking in osteoclasts - statement: Orthologs conserved across eukaryotic lineages with similar functions in yeast - id: file:rules/arba/ARBA00089175/ARBA00089175-deep-research-falcon.md title: Deep research analysis of PLEKHM1 structure and function (Falcon) findings: - statement: PLEKHM1 contains PH, RUN, RH, and LIR domains for multivalent adaptor function - statement: RUN domain binds Arl8b while RH domain binds Rab7 for dual GTPase engagement - statement: Central role in autophagosome-lysosome fusion as HOPS-interacting protein - statement: Evidence primarily from animal systems; plant/fungal orthologs less characterized - statement: Recommendation to use lysosome-specific terms for Metazoa vs vacuole terms for fungi/plants - id: https://www.ebi.ac.uk/QuickGO/term/GO:1990849 title: QuickGO entry for GO:1990849 vacuolar localization findings: - statement: Biological process term for vacuolar transport and maintenance