NCU04302 encodes a 157-residue Ubc9-family SUMO-conjugating E2 enzyme. Its conserved UBC catalytic domain and phylogenetic placement support transfer of activated SUMO to protein substrates, predominantly in the nucleus. SUMO modification provides a mechanism for regulating nuclear proteins; target-specific substrates and the distribution among nuclear subcompartments remain incompletely characterized.
Summary: The ortholog transfer from fission-yeast P40984 specifies heterochromatin.
Reason: The ortholog transfer from fission-yeast P40984 specifies heterochromatin. Nuclear SUMO conjugation is established at family level, but conserved residence in this particular chromatin compartment has not been verified for Neurospora.
Summary: Nuclear localization is supported by the conserved Ubc9 phylogenetic annotation at PTN000629675 and the nuclear SUMO-conjugation pathway.
Reason: Nuclear localization is supported by the conserved Ubc9 phylogenetic annotation at PTN000629675 and the nuclear SUMO-conjugation pathway. This is a family-based localization inference rather than direct imaging of NCU04302.
Summary: Nuclear localization is supported by the conserved Ubc9 phylogenetic annotation at PTN000629675 and the nuclear SUMO-conjugation pathway.
Reason: Nuclear localization is supported by the conserved Ubc9 phylogenetic annotation at PTN000629675 and the nuclear SUMO-conjugation pathway. This is a family-based localization inference rather than direct imaging of NCU04302.
Summary: Chromosome residence is more specific than the supported nuclear SUMO pathway.
Reason: Chromosome residence is more specific than the supported nuclear SUMO pathway. The ARBA chromosome assignment does not establish stable or regulated chromosome association of this protein, and target-specific localization evidence was not recovered.
Summary: Ubc9-mediated SUMO conjugation can support genome maintenance through modification of repair proteins.
Reason: Ubc9-mediated SUMO conjugation can support genome maintenance through modification of repair proteins. The fission-yeast ortholog transfer is biologically coherent, but DNA repair is one substrate-dependent role of a general SUMO E2 rather than its defining biochemical function.
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: Ubc9 catalyzes transfer of activated SUMO through a thioester intermediate; ATP-dependent modifier activation belongs to the E1 step.
Reason: Ubc9 catalyzes transfer of activated SUMO through a thioester intermediate; ATP-dependent modifier activation belongs to the E1 step. The more specific SUMO conjugating enzyme activity identifies the E2 chemistry and avoids the generic ATP-coupled ligase assignment.
Summary: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily.
Reason: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily. Biochemical work on yeast and mammalian Ubc9 establishes SUMO thioester formation, making SUMO conjugation a well-grounded conserved function. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily.
Reason: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily. Biochemical work on yeast and mammalian Ubc9 establishes SUMO thioester formation, making SUMO conjugation a well-grounded conserved function. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: SUMO transferase activity is a valid broad description of Ubc9-mediated covalent SUMO transfer.
Reason: SUMO transferase activity is a valid broad description of Ubc9-mediated covalent SUMO transfer. The conserved SUMO-E2 placement and Ubc9 biochemistry provide the biological support independently of this row’s electronic source. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: This EC:2.3.2.23 mapping specifies transfer of ubiquitin, whereas PAINT places NCU04302 in the SUMO-conjugating Ubc9 lineage.
Reason: This EC:2.3.2.23 mapping specifies transfer of ubiquitin, whereas PAINT places NCU04302 in the SUMO-conjugating Ubc9 lineage. The substrate distinction is mechanistic: the characterized Ubc9 homologs form SUMO thioesters. Replace the ubiquitin-specific activity with SUMO conjugating enzyme activity. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily.
Reason: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily. Biochemical work on yeast and mammalian Ubc9 establishes SUMO thioester formation, making SUMO conjugation a well-grounded conserved function. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily.
Reason: The UBC catalytic domain and PAINT placement at PTN000629675 support the Ubc9 SUMO-E2 subfamily. Biochemical work on yeast and mammalian Ubc9 establishes SUMO thioester formation, making SUMO conjugation a well-grounded conserved function. The target has modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, corroborated by 75% full-length identity to characterized fission-yeast Ubc9.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
Summary: Ubc9 participates in conserved SUMO-conjugation assemblies.
Reason: GO:0106068 includes a SUMO-protein transferase with other proteins that confer substrate specificity; it does not require a permanently stable assembly. The Ubc9-specific sequence assignment and conserved interactions with SUMO, substrates and E3 ligases support this broad complex annotation from the fission-yeast ortholog. No named Neurospora E3 partner or stoichiometry is inferred.
The SUMO E2 Ubc9 serves as a lynchpin in the SUMO conjugation pathway, interacting with the SUMO E1 during activation, with thioester linked SUMO after E1 transfer and with the substrate and SUMO E3 ligases during conjugation.
Core Functions
NCU04302 encodes a 157-residue Ubc9-family SUMO-conjugating E2 enzyme.
The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage).
The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation.
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.
Review rationale: The target is a Ubc9-family SUMO E2, supported by modifier-specific CDD UBCc_UBE2I and FunFam Ubc9 assignments, full-length similarity to characterized Ubc9, and the curated SUMO-specific PAINT inference. Characterized Ubc9 homologs form thioester intermediates with SUMO. Transferase activity is therefore correct but less precise than the existing SUMO conjugating enzyme activity. This broad GO result does not validate the separate ubiquitin-specific paragraph.
file:NEUCR/NCU04302/NCU04302-bioinformatics/RESULTS.md: "The full-length target sequence is 75.0% identical to fission-yeast Ubc9 P40984 across 156 aligned residue pairs (99.36% target coverage), and 62.42% identical to human Ubc9 P63279 across 157 residue pairs (100% target coverage)."
PMID:12597774: "The Hus5.62 protein is also capable of forming a thioester link with SUMO, but it does not function in sumoylation assays, either in the modification of Rad22 or in SUMO chain formation."