ARBA00035068

View original ARBA rule on UniProt

Type: ARBA
Status: COMPLETE
Action: MODIFY
Confidence: 0.75

Description

Assigns phosphatidylinositol-3-phosphate phosphatase activity (GO:0004438) to proteins containing myotubularin-related functional family domains, with condition set 1 targeting MTM1-related domains in Primates and condition set 2 targeting MTMR4-related domains across all Eukaryotes

Analysis Summary

Condition-set counts describe the sets recorded in this review, which may omit the full rule.

0
Domain Pairs Analyzed
2
Recorded condition sets
0
Subset Relationships
0
Redundant Annotations

Domain Overlap Analysis Table

Interactive prediction matrix showing how row entries PREDICT column entries. Cell (i,j) shows what fraction of proteins with row domain i also have column domain j. Click cells to view intersection in UniProt. Click domain IDs to view proteins with that domain.

CS 1
Primates 		CS 2
Eukaryota 		TGT EXT
ipr2go
Myotubularin 1, isoform C...
2.30.29.30:FF:000038
(15) 		myotubularin-related prot...
3.30.40.10:FF:000073
(19) 		phosphatidylinositol-3-ph...
GO:0004438 []
(81) 		IPR039802
IPR039802
(2) 		IPR046352
IPR046352
(3)
CS 1
Primates 		Myotubularin 1, isoform CRA_a
2.30.29.30:FF:000038 (15) 		100%
0%
J:0%
(0)
100%
J:19%
(15)
0%
J:0%
(0)
0%
J:0%
(0)
CS 2
Eukaryota 		myotubularin-related protein 4 isoform X2
3.30.40.10:FF:000073 (19)
0%
J:0%
(0) 		100%
100%
J:23%
(19)
0%
J:0%
(0)
16%
J:16%
(3)
TGT phosphatidylinositol-3-phosphate phosphatase activity
GO:0004438 [] (81)
19%
J:19%
(15)
23%
J:23%
(19) 		100%
2%
J:2%
(2)
4%
J:4%
(3)
EXT
ipr2go 		IPR039802
IPR039802 (2)
0%
J:0%
(0)
0%
J:0%
(0)
100%
J:2%
(2) 		100%
0%
J:0%
(0)
IPR046352
IPR046352 (3)
0%
J:0%
(0)
100%
J:16%
(3)
100%
J:4%
(3)
0%
J:0%
(0) 		100%

Legend: Each cell shows PREDICTS % (fraction of row entry proteins that also have column entry - row PREDICTS column), Jaccard similarity (J:%), and intersection count. CS = Condition Set(s), TGT = GO annotation target.

Review Summary

ARBA00035068 demonstrates solid biological foundation by correctly identifying myotubularin family proteins with established phosphatidylinositol-3-phosphate phosphatase activity. However, the rule exhibits significant taxonomic inconsistency (Primates vs all Eukaryotes) and lacks safeguards against pseudophosphatase false positives. The domain overlap analysis shows complete disjunction between condition sets, confirming they target distinct protein subfamilies. While the GO annotation is biochemically accurate, the rule would benefit from taxonomic harmonization and additional constraints to improve specificity. The rule captures functional diversity not present in existing InterPro2GO mappings, providing novel annotation coverage.

Action Rationale

The rule correctly identifies myotubularin phosphatase activity but suffers from taxonomic inconsistency and potential false positive risk. MTM1-related functions are arbitrarily restricted to Primates despite broader evolutionary conservation. The rule also lacks constraints to exclude pseudophosphatase family members that retain domains but lack catalytic activity. Harmonizing taxonomic scope and adding catalytic constraints would significantly improve specificity.

External Mappings (ipr2go)

These InterPro domains also map to the rule's GO term(s) via InterPro2GO but are not part of any condition set in this rule. They may represent alternative domain signatures that predict the same function.

IPR039802
ipr2go
Maps to:
GO:0004438
2 proteins in Swiss-Prot
IPR046352
ipr2go
Maps to:
GO:0004438
3 proteins in Swiss-Prot

Rule Definition

Condition Sets

Condition Set 1

2 condition(s)

Condition Set 2

2 condition(s)

Assessments

ACCEPTABLE

Rule structure is reasonably parsimonious with two distinct condition sets targeting different myotubularin subfamilies (MTM1 vs MTMR4). Complete disjunction between condition sets (Jaccard = 0.0) confirms they capture non-overlapping protein sets. However, taxonomic restrictions appear arbitrary and inconsistent, suggesting the rule could be simplified by harmonizing taxonomic scope across both condition sets.

STRONG

Extensive biochemical and structural evidence supports myotubularin phosphatidylinositol-3-phosphate phosphatase activity. MTM1 and MTMR4 are well-characterized family members with demonstrated substrate specificity and physiological relevance. However, family complexity includes pseudophosphatases that lack catalytic activity despite domain conservation.

Supporting Evidence:

  • file:rules/arba/ARBA00035068/ARBA00035068-deep-research-comprehensive.md: Myotubularins (MTMs) are dual-specificity phosphatases that specifically dephosphorylate phosphatidylinositol 3-phosphate (PtdIns3P) and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). MTM1 and MTMR4 both demonstrate PtdIns3P phosphatase activity in vitro and belong to the protein tyrosine phosphatase superfamily with conserved active sites.
NONE

Domain overlap analysis reveals complete disjunction between condition sets (Jaccard similarity = 0.0, intersection = 0 proteins). The two CATH FunFams target distinct myotubularin subfamily members with no protein overlap. This indicates the condition sets capture genuinely different protein populations, supporting the biological rationale for separate annotation paths.

APPROPRIATE

GO:0004438 (phosphatidylinositol-3-phosphate phosphatase activity) accurately describes the core biochemical function shared by both MTM1 and MTMR4 subfamily members. While some family members have dual substrate specificity (PtdIns3P and PtdIns(3,5)P2), the chosen term captures the primary conserved activity. More specific terms could distinguish substrate preferences but would require rule splitting.

TOO_NARROW

Significant taxonomic inconsistency exists: MTM1-related domains restricted to Primates while MTMR4-related domains span all Eukaryotes. This restriction appears arbitrary given that myotubularin activity is evolutionarily conserved and MTM1 orthologs exist in many non-primate mammals. The biological rationale for primate-specific restriction is unclear and likely reflects annotation bias rather than functional constraint.

References (1)

Raw YAML

View Source YAML 
id: ARBA00035068
description: 'Assigns phosphatidylinositol-3-phosphate phosphatase activity (GO:0004438) to proteins containing myotubularin-related functional family domains, with condition set 1 targeting MTM1-related domains in Primates and condition set 2 targeting MTMR4-related domains across all Eukaryotes'
status: COMPLETE
rule_type: ARBA
rule:
  rule_id: ARBA00035068
  condition_sets:
  - number: 1
    conditions:
    - condition_type: FUNFAM
      value: 2.30.29.30:FF:000038
      curie: CATH.FunFam:2.30.29.30:FF:000038
      label: Myotubularin 1, isoform CRA_a
      negated: false
    - condition_type: TAXON
      value: Primates
      curie: NCBITaxon:9443
      label: Primates
      negated: false
    notes: ''
  - number: 2
    conditions:
    - condition_type: FUNFAM
      value: 3.30.40.10:FF:000073
      curie: CATH.FunFam:3.30.40.10:FF:000073
      label: myotubularin-related protein 4 isoform X2
      negated: false
    - condition_type: TAXON
      value: Eukaryota
      curie: NCBITaxon:2759
      label: Eukaryota
      negated: false
    notes: ''
  go_annotations: []
  reviewed_protein_count: 0
  unreviewed_protein_count: 0
  created_date: ''
  modified_date: ''
  entries:
  - id: 2.30.29.30:FF:000038
    type: FUNFAM
    label: Myotubularin 1, isoform CRA_a
    appears_in_condition_sets:
    - 1
    protein_count: 15
    related_entries:
    - relationship: EQUIV
      target_id: 3.30.40.10:FF:000073
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 15
    - relationship: EQUIV
      target_id: IPR039802
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 15
    - relationship: EQUIV
      target_id: IPR046352
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 15
    - relationship: PREDICTS
      target_id: GO:0004438
      containment: 1.0
      jaccard_similarity: 0.185
      intersection_count: 15
      exclusive_count: 0
  - id: 3.30.40.10:FF:000073
    type: FUNFAM
    label: myotubularin-related protein 4 isoform X2
    appears_in_condition_sets:
    - 2
    protein_count: 19
    related_entries:
    - relationship: EQUIV
      target_id: 2.30.29.30:FF:000038
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 19
    - relationship: EQUIV
      target_id: IPR039802
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 19
    - relationship: PREDICTED_BY
      target_id: IPR046352
      containment: 1.0
      jaccard_similarity: 0.158
      intersection_count: 3
      exclusive_count: 0
    - relationship: PREDICTS
      target_id: GO:0004438
      containment: 1.0
      jaccard_similarity: 0.235
      intersection_count: 19
      exclusive_count: 0
  - id: IPR039802
    type: INTERPRO
    source: ipr2go
    protein_count: 2
    asserted_predicted_go_terms:
    - GO:0004438
    related_entries:
    - relationship: EQUIV
      target_id: 2.30.29.30:FF:000038
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 2
    - relationship: EQUIV
      target_id: 3.30.40.10:FF:000073
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 2
    - relationship: EQUIV
      target_id: IPR046352
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 2
    - relationship: PREDICTS
      target_id: GO:0004438
      containment: 1.0
      jaccard_similarity: 0.025
      intersection_count: 2
      exclusive_count: 0
  - id: IPR046352
    type: INTERPRO
    source: ipr2go
    protein_count: 3
    asserted_predicted_go_terms:
    - GO:0004438
    related_entries:
    - relationship: EQUIV
      target_id: 2.30.29.30:FF:000038
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 3
    - relationship: PREDICTS
      target_id: 3.30.40.10:FF:000073
      containment: 0.158
      jaccard_similarity: 0.158
      intersection_count: 3
      exclusive_count: 16
    - relationship: EQUIV
      target_id: IPR039802
      containment: 0.0
      jaccard_similarity: 0.0
      intersection_count: 0
      exclusive_count: 3
    - relationship: PREDICTS
      target_id: GO:0004438
      containment: 1.0
      jaccard_similarity: 0.037
      intersection_count: 3
      exclusive_count: 0
review_summary: 'ARBA00035068 demonstrates solid biological foundation by correctly identifying myotubularin family proteins with established phosphatidylinositol-3-phosphate phosphatase activity. However, the rule exhibits significant taxonomic inconsistency (Primates vs all Eukaryotes) and lacks safeguards against pseudophosphatase false positives. The domain overlap analysis shows complete disjunction between condition sets, confirming they target distinct protein subfamilies. While the GO annotation is biochemically accurate, the rule would benefit from taxonomic harmonization and additional constraints to improve specificity. The rule captures functional diversity not present in existing InterPro2GO mappings, providing novel annotation coverage.'
action: MODIFY
action_rationale: 'The rule correctly identifies myotubularin phosphatase activity but suffers from taxonomic inconsistency and potential false positive risk. MTM1-related functions are arbitrarily restricted to Primates despite broader evolutionary conservation. The rule also lacks constraints to exclude pseudophosphatase family members that retain domains but lack catalytic activity. Harmonizing taxonomic scope and adding catalytic constraints would significantly improve specificity.'
suggested_modifications:
- 'Harmonize taxonomic scope: expand MTM1 condition (set 1) from Primates to all Eukaryotes or restrict both to Vertebrates/Mammals'
- 'Add structural constraints to exclude pseudophosphatase family members lacking conserved catalytic residues'
- 'Consider more specific GO terms that distinguish substrate preferences (PtdIns3P vs PtdIns(3,5)P2)'
- 'Evaluate splitting into separate rules for MTM1 vs MTMR4 subfamilies given their distinct cellular roles'
parsimony:
  assessment: ACCEPTABLE
  notes: 'Rule structure is reasonably parsimonious with two distinct condition sets targeting different myotubularin subfamilies (MTM1 vs MTMR4). Complete disjunction between condition sets (Jaccard = 0.0) confirms they capture non-overlapping protein sets. However, taxonomic restrictions appear arbitrary and inconsistent, suggesting the rule could be simplified by harmonizing taxonomic scope across both condition sets.'
literature_support:
  assessment: STRONG
  notes: 'Extensive biochemical and structural evidence supports myotubularin phosphatidylinositol-3-phosphate phosphatase activity. MTM1 and MTMR4 are well-characterized family members with demonstrated substrate specificity and physiological relevance. However, family complexity includes pseudophosphatases that lack catalytic activity despite domain conservation.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00035068/ARBA00035068-deep-research-comprehensive.md
    supporting_text: 'Myotubularins (MTMs) are dual-specificity phosphatases that specifically dephosphorylate phosphatidylinositol 3-phosphate (PtdIns3P) and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P2). MTM1 and MTMR4 both demonstrate PtdIns3P phosphatase activity in vitro and belong to the protein tyrosine phosphatase superfamily with conserved active sites.'
condition_overlap:
  assessment: NONE
  notes: 'Domain overlap analysis reveals complete disjunction between condition sets (Jaccard similarity = 0.0, intersection = 0 proteins). The two CATH FunFams target distinct myotubularin subfamily members with no protein overlap. This indicates the condition sets capture genuinely different protein populations, supporting the biological rationale for separate annotation paths.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00035068/ARBA00035068-analysis.yaml
    supporting_text: 'condition_a: 2.30.29.30:FF:000038, condition_b: 3.30.40.10:FF:000073, intersection_count: 0, jaccard_similarity: 0.0, interpretation: DISJOINT'
go_specificity:
  assessment: APPROPRIATE
  notes: 'GO:0004438 (phosphatidylinositol-3-phosphate phosphatase activity) accurately describes the core biochemical function shared by both MTM1 and MTMR4 subfamily members. While some family members have dual substrate specificity (PtdIns3P and PtdIns(3,5)P2), the chosen term captures the primary conserved activity. More specific terms could distinguish substrate preferences but would require rule splitting.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00035068/ARBA00035068-deep-research-comprehensive.md
    supporting_text: 'Different myotubularin family members have distinct substrate preferences (PtdIns3P vs PtdIns(3,5)P2), kinetic parameters, cellular localization and regulation. The broad GO term GO:0004438 may not capture this functional diversity adequately, but correctly identifies the core conserved phosphatase activity.'
taxonomic_scope:
  assessment: TOO_NARROW
  notes: 'Significant taxonomic inconsistency exists: MTM1-related domains restricted to Primates while MTMR4-related domains span all Eukaryotes. This restriction appears arbitrary given that myotubularin activity is evolutionarily conserved and MTM1 orthologs exist in many non-primate mammals. The biological rationale for primate-specific restriction is unclear and likely reflects annotation bias rather than functional constraint.'
  supported_by:
  - reference_id: file:rules/arba/ARBA00035068/ARBA00035068-deep-research-comprehensive.md
    supporting_text: 'The rule applies different taxonomic restrictions to structurally and functionally related proteins: MTM1-related domains restricted to Primates only, MTMR4-related domains to all Eukaryotes. This inconsistency is problematic because myotubularin activity is conserved across eukaryotes and MTM1 orthologs exist in many non-primate mammals.'
confidence: 0.75
references:
- id: file:rules/arba/ARBA00035068/ARBA00035068-deep-research-comprehensive.md
  title: Comprehensive analysis of myotubularin family phosphatases
  findings:
  - statement: 'Myotubularins are dual-specificity phosphatases that specifically dephosphorylate PtdIns3P and PtdIns(3,5)P2, critical for endosomal membrane dynamics'
  - statement: 'MTM1 and MTMR4 represent distinct subfamilies with conserved phosphatase activity but different cellular localizations and substrate preferences'
  - statement: 'Family includes pseudophosphatases lacking catalytic activity but retaining regulatory functions'
  - statement: 'Taxonomic restriction to Primates for MTM1 lacks biological justification given evolutionary conservation'
supported_by:
- reference_id: file:rules/arba/ARBA00035068/ARBA00035068-analysis.yaml
  supporting_text: 'Complete disjunction between condition sets confirms distinct protein populations (intersection_count: 0, jaccard_similarity: 0.0)'