opa1

UniProt ID: Q5U3A7
Organism: Danio rerio
Review Status: DRAFT
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Gene Description

Opa1 is a mitochondrial dynamin-like GTPase that couples GTP hydrolysis to inner-membrane fusion and cristae remodeling. Membrane-anchored long and soluble intermembrane-space forms cooperate in membrane remodeling. In zebrafish, opa1 depletion disrupts mitochondrial morphology and respiration and impairs embryonic development and ventricular cardiomyocyte growth.

Existing Annotations Review

GO Term Evidence Action Reason
GO:0008053 mitochondrial fusion
IBA
GO_REF:0000033
ACCEPT
Summary: Opa1 performs GTP-dependent mitochondrial membrane fusion.
Reason: Opa1 is the conserved inner-membrane fusion GTPase. The zebrafish depletion study supports mitochondrial remodeling, and ortholog biochemistry supplies the molecular mechanism; broad membrane/mitochondrial fusion terms remain valid alongside the inner-membrane-specific term.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0031966 mitochondrial membrane
IBA
GO_REF:0000033
ACCEPT
Summary: Mitochondrial membrane is a valid broader localization for Opa1.
Reason: The inner mitochondrial membrane is within the scope of mitochondrial membrane. Specific localization does not invalidate its parent; PAINT places this localization at the OPA1-family node PTN007514526.
Propagation Review
Root cause: NO FAILURE CORE
Sources checked:
PANTHER:PTN007514526 SUPPORTS TRANSFER
Current PAINT IBD and live target lineage verified; zebrafish Opa1 descends from this OPA1 node.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0016559 peroxisome fission
IBA
GO_REF:0000033
UNDECIDED
Summary: The ancestral peroxisome fission inference remains unresolved for zebrafish Opa1.
Reason: Independent PANTHER v19 tree retrieval places Q5U3A7 below PTN008520527 and OPA1 node PTN007514526. Current PAINT has the corresponding IBD at PTN008520527; this is an ancestral claim, not a pairwise transfer invalidated by a different donor name. The shared EAT-3 OpenScientist report identifies native IMS topology and domain divergence as mechanistic concerns. These are relevant biological arguments, but the report does not resolve loss of this ancestrally placed function in OPA1. A negative assay is not required to reject an IBA; here the lineage and domain premises offered for rejection did not withstand independent checks. Preserve uncertainty pending adjudication of inheritance or loss in the OPA1 clade. Moreover, PMID:32228866 Fig. 1A explicitly identifies an OPA1 middle domain and GED, contradicting the report's inference of GED loss from missing database domain labels.
Propagation Review
Root cause: UNRESOLVED
Sources checked:
PANTHER:PTN008520527 UNRESOLVED
Verified ancestor of the exact zebrafish leaf PTN000170160 through OPA1 node PTN007514526. Source functions in other dynamin branches are credible; inheritance/loss in OPA1 is unresolved.
GO:0005758 mitochondrial intermembrane space
IBA
GO_REF:0000033
ACCEPT
Summary: The Opa1 catalytic machinery acts in the mitochondrial intermembrane space.
Reason: The soluble processed form occupies the intermembrane space and cooperates with inner-membrane-anchored Opa1. This inherited OPA1 localization is supported by the target record and PTN007514526; the long form does not exclude the soluble form.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
cleavage and localizes in the intermembrane space.
GO:0008017 microtubule binding
IBA
GO_REF:0000033
UNDECIDED
Summary: The ancestral microtubule binding inference remains unresolved for zebrafish Opa1.
Reason: Independent PANTHER v19 tree retrieval places Q5U3A7 below PTN000170013 and OPA1 node PTN007514526. Current PAINT has the corresponding IBD at PTN000170013; this is an ancestral claim, not a pairwise transfer invalidated by a different donor name. The shared EAT-3 OpenScientist report identifies native IMS topology and domain divergence as mechanistic concerns. These are relevant biological arguments, but the report does not resolve loss of this ancestrally placed function in OPA1. A negative assay is not required to reject an IBA; here the lineage and domain premises offered for rejection did not withstand independent checks. Preserve uncertainty pending adjudication of inheritance or loss in the OPA1 clade. Moreover, PMID:32228866 Fig. 1A explicitly identifies an OPA1 middle domain and GED, contradicting the report's inference of GED loss from missing database domain labels.
Propagation Review
Root cause: UNRESOLVED
Sources checked:
PANTHER:PTN000170013 UNRESOLVED
Verified ancestor of the exact zebrafish leaf PTN000170160 through OPA1 node PTN007514526. Source functions in other dynamin branches are credible; inheritance/loss in OPA1 is unresolved.
GO:0003924 GTPase activity
IEA
GO_REF:0000120
ACCEPT
Summary: GTP hydrolysis is part of the core Opa1 membrane-remodeling mechanism.
Reason: Opa1 itself consumes GTP by hydrolysis while driving membrane fusion. GTPase activity and GTP metabolic process are valid broader descriptions of work performed by the protein; a more specific fusogenic term does not make them over-annotations.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
Reaction=GTP + H2O = GDP + phosphate + H(+)
GO:0005525 GTP binding
IEA
GO_REF:0000002
ACCEPT
Summary: Opa1 binds GTP as the substrate of its dynamin-like GTPase domain.
Reason: Nucleotide binding is intrinsic to the conserved hydrolytic fusion mechanism, not a secondary developmental effect.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
Reaction=GTP + H2O = GDP + phosphate + H(+)
GO:0005743 mitochondrial inner membrane
IEA
GO_REF:0000044
ACCEPT
Summary: Long Opa1 is anchored in the mitochondrial inner membrane.
Reason: The long/short processing system positions Opa1 at the inner membrane and adjacent intermembrane space, matching the membrane-fusion machinery.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
inner mitochondrial membrane, and the short soluble form
GO:0005758 mitochondrial intermembrane space
IEA
GO_REF:0000044
ACCEPT
Summary: The Opa1 catalytic machinery acts in the mitochondrial intermembrane space.
Reason: The soluble processed form occupies the intermembrane space and cooperates with inner-membrane-anchored Opa1. This inherited OPA1 localization is supported by the target record and PTN007514526; the long form does not exclude the soluble form.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
cleavage and localizes in the intermembrane space.
GO:0061025 membrane fusion
IEA
GO_REF:0000108
ACCEPT
Summary: Opa1 performs GTP-dependent mitochondrial membrane fusion.
Reason: Opa1 is the conserved inner-membrane fusion GTPase. The zebrafish depletion study supports mitochondrial remodeling, and ortholog biochemistry supplies the molecular mechanism; broad membrane/mitochondrial fusion terms remain valid alongside the inner-membrane-specific term.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0003924 GTPase activity
ISS
GO_REF:0000024
ACCEPT
Summary: GTP hydrolysis is part of the core Opa1 membrane-remodeling mechanism.
Reason: Opa1 itself consumes GTP by hydrolysis while driving membrane fusion. GTPase activity and GTP metabolic process are valid broader descriptions of work performed by the protein; a more specific fusogenic term does not make them over-annotations.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
Reaction=GTP + H2O = GDP + phosphate + H(+)
GO:0005743 mitochondrial inner membrane
ISS
GO_REF:0000024
ACCEPT
Summary: Long Opa1 is anchored in the mitochondrial inner membrane.
Reason: The long/short processing system positions Opa1 at the inner membrane and adjacent intermembrane space, matching the membrane-fusion machinery.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
inner mitochondrial membrane, and the short soluble form
GO:0005758 mitochondrial intermembrane space
ISS
GO_REF:0000024
ACCEPT
Summary: The Opa1 catalytic machinery acts in the mitochondrial intermembrane space.
Reason: The soluble processed form occupies the intermembrane space and cooperates with inner-membrane-anchored Opa1. This inherited OPA1 localization is supported by the target record and PTN007514526; the long form does not exclude the soluble form.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
cleavage and localizes in the intermembrane space.
GO:0032740 positive regulation of interleukin-17 production
ISS
GO_REF:0000024
KEEP AS NON CORE
Summary: Opa1 has a conserved, context-specific role in supporting IL-17 production.
Reason: The actual ISS donor is mouse Opa1 P58281, with IMP evidence from PMID:36171294. Its T-cell-specific deletion reduces IL-17A independently of cell division, early activation, and restored respiration; OPA1-dependent metabolic signaling therefore supports cytokine output. Ortholog transfer to zebrafish is plausible but remains an inference, and this immune context is noncore relative to membrane remodeling.
Propagation Review
Root cause: NO FAILURE NON CORE
Sources checked:
UniProtKB:P58281 SUPPORTS TRANSFER
Live QuickGO donor IMP PMID:36171294 and full primary verified; supports OPA1-dependent IL-17 production. Target immune context is inferred.
Supporting Evidence:
PMID:36171294
Thus, OPA1 sustains cytokine production in TH17 cells in vitro, but not early differentiation events associated with transcription factor expression.
GO:2000330 positive regulation of T-helper 17 cell lineage commitment
ISS
GO_REF:0000024
MODIFY
Summary: The donor study supports IL-17 effector output more clearly than Th17 lineage commitment.
Reason: Full PMID:36171294 explicitly distinguishes impaired IL-17A production from intact early lineage-specifying transcription-factor expression. Late effects on maintenance and RORgamma-t do not by themselves demonstrate the initial lineage-commitment step. Retain the biological immune effect using positive regulation of IL-17 production, also already represented by its own source annotation; no additional NEW row is proposed.
Propagation Review
Root cause: TERM SCOPING PROBLEM
Sources checked:
UniProtKB:P58281 SUPPORTS SOURCE BUT NOT TARGET
Actual source supports cytokine production and tissue maintenance; Fig. 1 and text report intact early lineage-factor expression.
Supporting Evidence:
PMID:36171294
Thus, OPA1 sustains cytokine production in TH17 cells in vitro, but not early differentiation events associated with transcription factor expression.
GO:0097749 membrane tubulation
ISS
GO_REF:0000024
ACCEPT
Summary: Opa1 assemblies deform and tubulate mitochondrial inner membranes.
Reason: Conserved OPA1 helical assembly and membrane engagement perform physical membrane remodeling. These ISS terms describe the direct molecular mechanism underlying cristae architecture and fusion, rather than a phenotype-only inference.
Supporting Evidence:
PMID:32228866
hydrophobic residues in its extended membrane-binding domain are critical for its tubulation activity.
GO:0180020 membrane bending activity
ISS
GO_REF:0000024
ACCEPT
Summary: Opa1 assemblies deform and tubulate mitochondrial inner membranes.
Reason: Conserved OPA1 helical assembly and membrane engagement perform physical membrane remodeling. These ISS terms describe the direct molecular mechanism underlying cristae architecture and fusion, rather than a phenotype-only inference.
Supporting Evidence:
PMID:32228866
hydrophobic residues in its extended membrane-binding domain are critical for its tubulation activity.
GO:1990627 mitochondrial inner membrane fusion
ISS
GO_REF:0000024
ACCEPT
Summary: Opa1 performs GTP-dependent mitochondrial membrane fusion.
Reason: Opa1 is the conserved inner-membrane fusion GTPase. The zebrafish depletion study supports mitochondrial remodeling, and ortholog biochemistry supplies the molecular mechanism; broad membrane/mitochondrial fusion terms remain valid alongside the inner-membrane-specific term.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0140523 GTPase-dependent fusogenic activity
ISS
GO_REF:0000024
ACCEPT
Summary: Opa1 performs GTP-dependent mitochondrial membrane fusion.
Reason: Opa1 is the conserved inner-membrane fusion GTPase. The zebrafish depletion study supports mitochondrial remodeling, and ortholog biochemistry supplies the molecular mechanism; broad membrane/mitochondrial fusion terms remain valid alongside the inner-membrane-specific term.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
file:DANRE/opa1/opa1-uniprot.txt
Reaction=GTP + H2O = GDP + phosphate + H(+)
GO:0055015 ventricular cardiac muscle cell development
IMP
PMID:25022898
Tom70 serves as a molecular switch to determine pathological...
KEEP AS NON CORE
Summary: Zebrafish Opa1 supports ventricular cardiomyocyte growth and morphology.
Reason: The full Tom70 paper directly tests Opa1 knockdown in zebrafish: Fig. 6H shows enlarged ventricular myocytes at 2 dpf, with fragmented mitochondria and blurred cristae. This is genuine target evidence despite the Tom70-focused title. Retain the contextual cardiac-development annotation without treating the experiment as proof of a dedicated early cardiac-lineage program.
Supporting Evidence:
PMID:25022898
The inactivation of Opa1 obviously enlarged the ventricular myocytes at 2 dpf
GO:0008053 mitochondrial fusion
ISS
GO_REF:0000024
ACCEPT
Summary: Opa1 performs GTP-dependent mitochondrial membrane fusion.
Reason: Opa1 is the conserved inner-membrane fusion GTPase. The zebrafish depletion study supports mitochondrial remodeling, and ortholog biochemistry supplies the molecular mechanism; broad membrane/mitochondrial fusion terms remain valid alongside the inner-membrane-specific term.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0046039 GTP metabolic process
ISS
GO_REF:0000024
ACCEPT
Summary: GTP hydrolysis is part of the core Opa1 membrane-remodeling mechanism.
Reason: Opa1 itself consumes GTP by hydrolysis while driving membrane fusion. GTPase activity and GTP metabolic process are valid broader descriptions of work performed by the protein; a more specific fusogenic term does not make them over-annotations.
Supporting Evidence:
file:DANRE/opa1/opa1-uniprot.txt
Reaction=GTP + H2O = GDP + phosphate + H(+)
GO:0070300 phosphatidic acid binding
ISS
GO_REF:0000024
ACCEPT
Summary: phosphatidic acid binding supports Opa1 membrane remodeling.
Reason: The actual human OPA1 donor has direct liposome-binding evidence in PMID:20185555 Fig. 2A: OPA1-S1 binds phosphatidic-acid-containing liposomes and binding stimulates GTP hydrolysis. This is a real molecular capacity despite cardiolipin being the likely predominant physiological lipid. The zebrafish ISS assertion is retained as conserved membrane-remodeling capacity; target biochemical specificity remains inferred.
Supporting Evidence:
PMID:20185555
OPA1-S1 associates strongly with liposomes containing 25% phosphatidic acid (POPA) or 25% phosphoserine (POPS)
GO:1901612 cardiolipin binding
ISS
GO_REF:0000024
ACCEPT
Summary: cardiolipin binding supports Opa1 membrane remodeling.
Reason: The curated ISS assertion concerns lipid engagement of the conserved OPA1 membrane-remodeling machinery. Cardiolipin engagement is explicit in the target record; phosphatidic-acid specificity is transferred by curator judgment rather than measured in the zebrafish developmental paper. Neither specificity is excluded by Opa1 having a fusion role.
Supporting Evidence:
PMID:20185555
OPA1 can promote the protrusion of lipid tubules from the surface of cardiolipin-containing liposomes.
GO:0007005 mitochondrion organization
IMP
PMID:23516612
Opa1 is required for proper mitochondrial metabolism in earl...
ACCEPT
Summary: Opa1 maintains mitochondrial morphology in zebrafish.
Reason: The full target study reports fragmented mitochondria after opa1 depletion, consistent with direct membrane-fusion/remodeling work. Mitochondrion organization is a valid core parent process.
Supporting Evidence:
PMID:23516612
Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
GO:0043009 chordate embryonic development
IMP
PMID:23516612
Opa1 is required for proper mitochondrial metabolism in earl...
KEEP AS NON CORE
Summary: Opa1 function supports zebrafish embryonic development.
Reason: The target study documents growth delay, smaller eyes, edema and impaired cardiac/locomotor performance after depletion. These developmental requirements are retained as context-specific consequences of mitochondrial function; they are not added to the core molecular-function summary.
Supporting Evidence:
PMID:23516612
Opa1 morphants had smaller eyes and eye edema at later stages.

Core Functions

Opa1 hydrolyzes GTP to drive mitochondrial inner membrane fusion and membrane remodeling, maintaining mitochondrial morphology.

Supporting Evidence:
  • file:DANRE/opa1/opa1-uniprot.txt
    Reaction=GTP + H2O = GDP + phosphate + H(+)
  • PMID:23516612
    Opa1 catalyzes fusion of inner mitochondrial membranes and formation of the cristae
  • file:DANRE/opa1/opa1-deep-research-falcon.md
    its catalytic activity is **GTP hydrolysis (GTP β†’ GDP + Pi)**, coupled to conformational changes that power membrane remodeling, tethering, and fusion.

References

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Deep Research

Falcon

(opa1-deep-research-falcon.md)

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πŸ“š Additional Documentation

Notes

(opa1-notes.md)

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