A0BFB4 (GSPATT00028266001) is a 381-residue Paramecium tetraurelia serine/threonine protein kinase with conserved ATP-binding and catalytic-site signatures. Its placement below the autophagy-bearing Atg1/ULK ancestor supports an inherited role in autophagosome assembly and regulation, with cytoplasmic and autophagic membrane-associated pools. The exact protein substrates and regulation in Paramecium remain uncharacterized.
Reason: PAINT infers this location from the kinase lineage. Broadness, overlap with another compartment term and lack of target microscopy are not biological objections. This is accepted as an evolutionary localization inference, not as a default inferred merely from solubility. It does not resolve the more specific autophagic compartment assignment.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
Broad catalytic, nucleotide-binding, cytoplasmic and membrane annotations remain supported.
Reason: PAINT infers this location from the kinase lineage. Broadness, overlap with another compartment term and lack of target microscopy are not biological objections. This is accepted as an evolutionary localization inference, not as a default inferred merely from solubility. It does not resolve the more specific autophagic compartment assignment.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
Broad catalytic, nucleotide-binding, cytoplasmic and membrane annotations remain supported.
Summary: Retain the autophagy assignment supported by the inspected PAINT lineage.
Reason: The actual PTHR24348 tree identifies target leaf PTN002805316 (A0BFB4/GSPATT00028266001) as a descendant of PTN000681272, where the autophagy functions were placed from Atg1/ULK experimental descendants. This verifies the relevant ancestral placement; the specific function is accepted as inherited, without claiming a target assay. Current UniProt/InterPro assigns PTHR44167:SF18, a resource-classification discrepancy that warrants reconciliation but does not by itself refute the inspected tree or demonstrate functional loss. Compact ciliate architecture, overlapping terms and the family label are not counterevidence.
Propagation Review
Root cause:NO FAILURE CORE
Sources checked:
PANTHER:PTN000681272SUPPORTS TRANSFER
The actual nested PAINT tree was inspected: A0BFB4 leaf PTN002805316 descends from this function-bearing ancestor, with no target-specific loss established.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
The actual tree therefore confirms that A0BFB4 descends from the autophagy-bearing ancestral node.
Summary: Retain the autophagy assignment supported by the inspected PAINT lineage.
Reason: The actual PTHR24348 tree identifies target leaf PTN002805316 (A0BFB4/GSPATT00028266001) as a descendant of PTN000681272, where the autophagy functions were placed from Atg1/ULK experimental descendants. This verifies the relevant ancestral placement; the specific function is accepted as inherited, without claiming a target assay. Current UniProt/InterPro assigns PTHR44167:SF18, a resource-classification discrepancy that warrants reconciliation but does not by itself refute the inspected tree or demonstrate functional loss. Compact ciliate architecture, overlapping terms and the family label are not counterevidence.
Propagation Review
Root cause:NO FAILURE CORE
Sources checked:
PANTHER:PTN000681272SUPPORTS TRANSFER
The actual nested PAINT tree was inspected: A0BFB4 leaf PTN002805316 descends from this function-bearing ancestor, with no target-specific loss established.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
The actual tree therefore confirms that A0BFB4 descends from the autophagy-bearing ancestral node.
Summary: Retain the autophagy assignment supported by the inspected PAINT lineage.
Reason: The actual PTHR24348 tree identifies target leaf PTN002805316 (A0BFB4/GSPATT00028266001) as a descendant of PTN000681272, where the autophagy functions were placed from Atg1/ULK experimental descendants. This verifies the relevant ancestral placement; the specific function is accepted as inherited, without claiming a target assay. Current UniProt/InterPro assigns PTHR44167:SF18, a resource-classification discrepancy that warrants reconciliation but does not by itself refute the inspected tree or demonstrate functional loss. Compact ciliate architecture, overlapping terms and the family label are not counterevidence.
Propagation Review
Root cause:NO FAILURE CORE
Sources checked:
PANTHER:PTN000681272SUPPORTS TRANSFER
The actual nested PAINT tree was inspected: A0BFB4 leaf PTN002805316 descends from this function-bearing ancestor, with no target-specific loss established.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
The actual tree therefore confirms that A0BFB4 descends from the autophagy-bearing ancestral node.
Summary: Retain the autophagy assignment supported by the inspected PAINT lineage.
Reason: The actual PTHR24348 tree identifies target leaf PTN002805316 (A0BFB4/GSPATT00028266001) as a descendant of PTN000681272, where the autophagy functions were placed from Atg1/ULK experimental descendants. This verifies the relevant ancestral placement; the specific function is accepted as inherited, without claiming a target assay. Current UniProt/InterPro assigns PTHR44167:SF18, a resource-classification discrepancy that warrants reconciliation but does not by itself refute the inspected tree or demonstrate functional loss. Compact ciliate architecture, overlapping terms and the family label are not counterevidence.
Propagation Review
Root cause:NO FAILURE CORE
Sources checked:
PANTHER:PTN000681272SUPPORTS TRANSFER
The actual nested PAINT tree was inspected: A0BFB4 leaf PTN002805316 descends from this function-bearing ancestor, with no target-specific loss established.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-placement-evidence.md
The actual tree therefore confirms that A0BFB4 descends from the autophagy-bearing ancestral node.
GO:0004674 protein serine/threonine kinase activity
IBA GO_REF:0000033
ACCEPT
Summary: Protein serine/threonine kinase activity is inferred by phylogenetic annotation from a broad set of orthologs across yeast, fly, worm, mouse, human, and fission yeast. This molecular function annotation is strongly supported by the domain architecture: A0BFB4 contains a protein kinase domain (PF00069) with a Ser/Thr kinase active site (IPR008271) and conserved ATP-binding site (IPR017441). The Ser/Thr kinase active site signature specifically supports serine/threonine rather than tyrosine kinase activity. This is the most well-supported annotation for this protein.
Reason: Strongly supported by both phylogenetic inference and domain architecture. The protein has a canonical Ser/Thr kinase domain with conserved active-site and ATP-binding residues. This is the core molecular function of the protein.
Reason: PAINT infers this location from the kinase lineage. Broadness, overlap with another compartment term and lack of target microscopy are not biological objections. This is accepted as an evolutionary localization inference, not as a default inferred merely from solubility. It does not resolve the more specific autophagic compartment assignment.
Summary: Retain the broad nucleotide binding annotation.
Reason: Nucleotide binding is intrinsic to the ATP-dependent kinase catalytic domain; the ATP-binding signatures support this core ligand-binding property. The ATP-binding-site and serine/threonine-kinase active-site signatures support the catalytic machinery. The specific kinase activity entails the broader nucleotide-binding/phosphotransfer classes; existing specific terms do not invalidate true ancestor annotations.
Summary: Retain the broad protein kinase activity annotation.
Reason: Protein kinase activity describes phosphate transfer to a protein substrate, supported by the protein-kinase domain and Ser/Thr active-site signatures without claiming a particular target substrate. The ATP-binding-site and serine/threonine-kinase active-site signatures support the catalytic machinery. The specific kinase activity entails the broader nucleotide-binding/phosphotransfer classes; existing specific terms do not invalidate true ancestor annotations.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-uniprot.txt
Protein_kinase_ATP_BS.
file:PARTE/A0BFB4/A0BFB4-uniprot.txt
Ser/Thr_kinase_AS.
GO:0004674 protein serine/threonine kinase activity
IEA GO_REF:0000120
ACCEPT
Summary: This is a second annotation of protein serine/threonine kinase activity, from the combined IEA pipeline (GO_REF:0000120) based on EC:2.7.11.1 and UniRule. This duplicates the IBA annotation of the same term (GO:0004674) with electronic rather than phylogenetic evidence, providing independent corroboration from domain architecture. Both the IBA phylogenetic inference and this IEA domain-based inference converge on the same core molecular function.
Reason: Protein serine/threonine kinase activity is strongly supported by both phylogenetic inference (IBA) and domain architecture (IEA). This IEA annotation provides independent corroboration of the core molecular function.
Summary: ATP binding is inferred from the protein kinase domain (IPR000719), the ATP-binding site signature (IPR017441), and UniRule. All protein kinases bind ATP as a phosphate donor. A0BFB4 has a conserved ATP-binding site (residue 125 annotated as ATP-binding in UniProt). This is a well-supported, core molecular function annotation.
Reason: ATP binding is a fundamental requirement for kinase catalytic activity, strongly supported by the conserved ATP-binding site and domain architecture. This is a core molecular function annotation.
Summary: Retain the broad kinase activity annotation.
Reason: Kinase activity describes the phosphotransfer reaction of the catalytic domain and is part of its conserved molecular role. The ATP-binding-site and serine/threonine-kinase active-site signatures support the catalytic machinery. The specific kinase activity entails the broader nucleotide-binding/phosphotransfer classes; existing specific terms do not invalidate true ancestor annotations.
Summary: Retain the broad transferase activity annotation.
Reason: Transferase activity covers the phosphate-group transfer performed by the kinase domain; it is not an unrelated or peripheral activity. The ATP-binding-site and serine/threonine-kinase active-site signatures support the catalytic machinery. The specific kinase activity entails the broader nucleotide-binding/phosphotransfer classes; existing specific terms do not invalidate true ancestor annotations.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-uniprot.txt
Protein_kinase_ATP_BS.
file:PARTE/A0BFB4/A0BFB4-uniprot.txt
Ser/Thr_kinase_AS.
Core Functions
Inferred ATP-dependent protein serine/threonine phosphorylation in autophagosome assembly and regulation, supported by conserved catalytic signatures and verified descent from the function-bearing Atg1/ULK ancestor.
Q: Why does live UniProt/InterPro classify A0BFB4 as PTHR44167:SF18 while the actual PAINT PTHR24348 tree explicitly places it below PTN000681272 (inherited PTHR24348:SF22)? Does any independent sequence/phylogenetic evidence overturn the presently supported Atg1/ULK functional inheritance?
External Prediction Reviews
These computational predictions are reviewed separately from the GOA annotation set used for this review. The assessments below are from this project and do not constitute official GO annotations or endorsement by GO/UniProt. They are not included in the existing annotation review above.
Prediction method: ProtNLM2 · Version: UniProt 2024_06 pilot
Review rationale: The target has a protein kinase domain at residues 96–348 together with protein-kinase ATP-binding and serine/threonine-kinase active-site signatures. These features support the curated IBA protein serine/threonine kinase activity and provide a mechanistic basis for protein phosphorylation. The process term itself is absent from the cached annotations, so the prediction adds an explicit biological-process annotation. It follows from the supported catalytic activity and does not identify a new substrate or autophagy mechanism.
Supporting Evidence:
file:PARTE/A0BFB4/A0BFB4-uniprot.txt: "ID A0BFB4_PARTE Unreviewed; 381 AA. ... DR GO; GO:0005776; C:autophagosome; IBA:GO_Central. ... DR GO; GO:0005737; C:cytoplasm; IBA:GO_Central. ... DR GO; GO:0005829; C:cytosol; IBA:GO_Central. ... DR GO; GO:0016020; C:membrane; IBA:GO_Central. ... DR GO; GO:0000407; C:phagophore assembly site; IBA:GO_Central. ... DR GO; GO:0004674; F:protein serine/threonine kinase activity; IBA:GO_Central. ... DR GO; GO:0000045; P:autophagosome assembly; IBA:GO_Central. ... DR GO; GO:0010506; P:regulation of autophagy; IBA:GO_Central. ... DR InterPro; IPR000719; Prot_kinase_dom. ... DR InterPro; IPR017441; Protein_kinase_ATP_BS. ... DR InterPro; IPR008271; Ser/Thr_kinase_AS. ... FT DOMAIN 96..348 ... FT /note="Protein kinase""