sod2 encodes the manganese superoxide dismutase of Schizosaccharomyces pombe, a homodimeric enzyme of the Fe/Mn SOD family that contains only manganese as cofactor and dismutates superoxide to hydrogen peroxide and dioxygen (EC 1.15.1.1). It is imported into the mitochondrial matrix, where a 21-residue N-terminal targeting sequence is removed, and is acetylated on Lys25 after import. Unlike budding yeast Sod2, the S. pombe enzyme is already active before mitochondrial import, but mitochondrial localization is required for oxidative stress resistance and respiratory growth. sod2 is induced by superoxide generators, high osmolarity and heat through the Wis1-Sty1 MAP kinase pathway, independently of Atf1 and Pap1, and sod2 mutants are sensitive to superoxide generators, heat and osmotic stress.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0004784 superoxide dismutase activity | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA superoxide dismutase activity for the Fe/Mn SOD family. Reason: Core activity; S. pombe sod2 is itself an experimental source. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. file:SCHPO/sod2/sod2-uniprot.txt Reaction=2 superoxide + 2 H(+) = H2O2 + O2; Xref=Rhea:RHEA:20696, |
| GO:0004784 superoxide dismutase activity | IDA PMID:11350071 Characterization of the manganese-containing superoxide dism... | ACCEPT | Summary: Jeong et al. 2001 purified the sod2 gene product and showed it is a genuine MnSOD. Reason: Core molecular function. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. |
| GO:0004784 superoxide dismutase activity | IDA PMID:21295010 Mitochondrial localization of fission yeast manganese supero... | ACCEPT | Summary: Takahashi et al. 2011: Sod2 is enzymatically active even when mislocalized outside mitochondria. Reason: Direct activity data; also an S. pombe-specific difference from budding yeast, where Mn loading and activation require mitochondrial import. Supporting Evidence: PMID:21295010 Mitochondrial localization of MnSOD is not essential for the enzyme activity, but is crucial for oxidative stress resistance and growth under respiratory conditions of fission yeast. PMID:21295010 S. pombe MnSOD is already active even before mitochondrial localization |
| GO:0004784 superoxide dismutase activity | IEA GO_REF:0000120 | ACCEPT | Summary: Combined IEA (ARBA, InterPro Fe/Mn SOD signatures, RHEA:20696, EC 1.15.1.1). Supporting Evidence: file:SCHPO/sod2/sod2-uniprot.txt Reaction=2 superoxide + 2 H(+) = H2O2 + O2; Xref=Rhea:RHEA:20696, |
| GO:0004784 superoxide dismutase activity | ISS GO_REF:0000024 | ACCEPT | Summary: ISS from a characterised bacterial MnSOD (P0A0J3). Reason: Redundant with direct S. pombe evidence but correct. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. file:SCHPO/sod2/sod2-uniprot.txt SIMILARITY: Belongs to the iron/manganese superoxide dismutase family. |
| GO:0005515 protein binding | IPI PMID:11350071 Characterization of the manganese-containing superoxide dism... | MODIFY | Summary: protein binding (IPI with Sod2 itself): the native enzyme consists of two identical subunits. Reason: Bare protein binding is uninformative; the self-interaction is homodimerization. Proposed replacements: protein homodimerization activity Supporting Evidence: PMID:11350071 The native form consisted of two identical subunits. |
| GO:0005739 mitochondrion | HDA PMID:16823372 ORFeome cloning and global analysis of protein localization ... | ACCEPT | Summary: ORFeome YFP localization: Sod2 in mitochondria. Supporting Evidence: PMID:16823372 we determined the localization of 4,431 proteins, corresponding to approximately 90% of the fission yeast proteome, by tagging each ORF with the yellow fluorescent protein. PMID:11350071 It was localized in mitochondria as expected. |
| GO:0005739 mitochondrion | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA is_active_in mitochondrion for the eukaryotic MnSOD clade. Reason: Confirmed experimentally for S. pombe Sod2. Supporting Evidence: PMID:11350071 It was localized in mitochondria as expected. |
| GO:0005739 mitochondrion | IDA PMID:11350071 Characterization of the manganese-containing superoxide dism... | ACCEPT | Summary: Sod2 localized in mitochondria with removal of a 21-residue targeting sequence. Supporting Evidence: PMID:11350071 It was localized in mitochondria as expected. PMID:11350071 Its N-terminal amino acid sequence indicated that the mitochondrial targeting sequence of 21 amino acids was removed. |
| GO:0005739 mitochondrion | IEA GO_REF:0000117 | ACCEPT | Summary: ARBA mitochondrion prediction. Reason: Correct; matrix is more specific. Supporting Evidence: PMID:11350071 It was localized in mitochondria as expected. |
| GO:0005759 mitochondrial matrix | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping of Mitochondrion matrix (from PMID:11350071). Supporting Evidence: file:SCHPO/sod2/sod2-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion matrix PMID:11350071 Its N-terminal amino acid sequence indicated that the mitochondrial targeting sequence of 21 amino acids was removed. |
| GO:0005759 mitochondrial matrix | ISO GO_REF:0000024 | ACCEPT | Summary: ISO mitochondrial matrix from S. cerevisiae Sod2 (SGD:S000001050). Reason: Agrees with the processed presequence and UniProt matrix location for S. pombe Sod2. Supporting Evidence: file:SCHPO/sod2/sod2-uniprot.txt SUBCELLULAR LOCATION: Mitochondrion matrix PMID:11350071 Its N-terminal amino acid sequence indicated that the mitochondrial targeting sequence of 21 amino acids was removed. |
| GO:0006801 superoxide metabolic process | IEA GO_REF:0000002 | KEEP AS NON CORE | Summary: InterPro2GO superoxide metabolic process. Reason: Correct but broader than removal of superoxide radicals, which is annotated experimentally; kept as non-core as in the S. cerevisiae SOD2 review. Supporting Evidence: file:SCHPO/sod2/sod2-uniprot.txt Reaction=2 superoxide + 2 H(+) = H2O2 + O2; Xref=Rhea:RHEA:20696, |
| GO:0019430 removal of superoxide radicals | IMP PMID:11350071 Characterization of the manganese-containing superoxide dism... | ACCEPT | Summary: sod2 disruption renders cells sensitive to superoxide generators, heat and high osmolarity. Reason: Core process. Supporting Evidence: PMID:11350071 The sod2 disruption rendered cells sensitive to various superoxide-generators, heat, and high osmolarity, suggesting that the mitochondrial MnSOD acts as a general defense agent against multiple stresses. |
| GO:0019430 removal of superoxide radicals | IMP PMID:21295010 Mitochondrial localization of fission yeast manganese supero... | ACCEPT | Summary: Mitochondrial localization of Sod2 is needed for oxidative stress resistance and respiratory growth. Supporting Evidence: PMID:21295010 Mitochondrial localization of MnSOD is not essential for the enzyme activity, but is crucial for oxidative stress resistance and growth under respiratory conditions of fission yeast. |
| GO:0030145 manganese ion binding | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT IBA manganese ion binding for MnSODs. Reason: Purified Sod2 contains only manganese. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. |
| GO:0030145 manganese ion binding | IDA PMID:11350071 Characterization of the manganese-containing superoxide dism... | ACCEPT | Summary: Purified Sod2 contains only manganese as cofactor. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. |
| GO:0046872 metal ion binding | IEA GO_REF:0000002 | TOO GENERAL | Summary: InterPro2GO generic metal ion binding. Reason: True but uninformative; manganese ion binding (GO:0030145) is annotated with direct evidence. Supporting Evidence: PMID:11350071 Purification and analysis of the sod2+ gene product revealed that it contained only manganese as a cofactor, thus verified to be a genuine MnSOD. |
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Download this section (compressed HTML)Q: How does S. pombe Sod2 acquire manganese before mitochondrial import, given that budding yeast Sod2 is only metallated inside mitochondria, and does Lys25 acetylation regulate its activity?
Experiment: Compare metal content and specific activity of Sod2 purified from cytosol-retained (presequence-deleted) and mitochondrial forms, and test K25R/K25Q mutants for activity and stress resistance.
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