oar2

Summary: 3-oxoacyl-ACP reductase activity (combined IEA mapping).

Reason: UniProt records the NADPH-dependent 3-oxoacyl-[ACP] reductase reaction (EC 1.1.1.100) for Oar2; there is no S. pombe enzyme assay, and the assignment rests on SDR family membership, PANTHER placement in the 3-oxoacyl-ACP reductase subfamily, the conserved SDR catalytic tetrad residues (proton acceptor by PROSITE rule; others by similarity to UniProtKB:O93868) and NADP(+)-binding residues, and transfer from the characterized S. cerevisiae ortholog Oar1.

Summary: 3-oxoacyl-ACP reductase activity (ISO transfer from S. cerevisiae Oar1).

Reason: UniProt records the NADPH-dependent 3-oxoacyl-[ACP] reductase reaction (EC 1.1.1.100) for Oar2; there is no S. pombe enzyme assay, and the assignment rests on SDR family membership, PANTHER placement in the 3-oxoacyl-ACP reductase subfamily, the conserved SDR catalytic tetrad residues (proton acceptor by PROSITE rule; others by similarity to UniProtKB:O93868) and NADP(+)-binding residues, and transfer from the characterized S. cerevisiae ortholog Oar1.

Summary: ORFeome YFP screen: mitochondrion.

Summary: UniProt subcellular location mapping; consistent.

Reason: UniProt's mitochondrion location for Oar2 is experimental, from the S. pombe ORFeome localization screen (PMID:16823372, also the source of the separate HDA row); the mapping row restates that observation.

Summary: Mitochondrial type II fatty acid synthesis (PAINT).

Reason: UniProt assigns Oar2 to mitochondrial fatty acid biosynthesis by similarity (to S. cerevisiae Oar1) and records the 3-oxoacyl-ACP reductase reaction, the first reduction step of each FAS elongation cycle; its mitochondrial location is experimental (PMID:16823372). No S. pombe genetic data on fatty acid synthesis are cited.

Summary: Mitochondrial type II fatty acid synthesis (UniPathway mapping).

Reason: Same claim as the IBA row: UniProt assigns Oar2 to fatty acid biosynthesis (pathway and by-similarity function) and records the 3-oxoacyl-ACP reductase reaction.

Summary: Curator inference to lipoate biosynthesis, a term now obsolete in GO. Oar2 is a 3-oxoacyl-ACP reductase of mitochondrial fatty acid synthesis, which supplies the octanoyl precursor of lipoic acid; it does not itself act in lipoate synthesis.

Reason: The term is obsolete in current GO (GO:0009107, obsolete lipoate biosynthetic process). By similarity (UniProt ECO:0000250) Oar2 is the 3-oxoacyl-ACP reductase of mitochondrial type II fatty acid synthesis, and mtFAS produces the octanoyl-ACP precursor from which lipoic acid is made (reviewed in Angerer 2015, on the general eukaryotic pathway). That makes Oar2 a supplier of the pathway's precursor, required for it rather than doing a step of it, so the process claim over-reaches; its own role is captured by the mitochondrial fatty acid biosynthesis rows. Pathway-level inference, not an S. pombe experiment.

Summary: PAINT inference of the generic SDR oxidoreductase activity; correct at family level, with the specific 3-oxoacyl-ACP reductase activity annotated.

Reason: Correct but uninformative. Oar2 is an SDR-family member (InterPro IPR002347, PROSITE ADH_SHORT) whose curated reaction is NADPH-dependent 3-oxoacyl-ACP reduction; GO:0004316, asserted in this review, is_a this term. The PAINT node placement is not in question.

Summary: IBA for quinone binding from node PTN002449501 (sourced from human CBR4); S. pombe Oar2 is a mitochondrial 3-oxoacyl-ACP reductase in type II fatty acid synthesis with no evidence of the mammalian CBR4/HSD17B8 complex's in vitro quinone reductase side activity.

Reason: Propagated from the Opisthokonta node PANTHER:PTN002449501 (seeded by human CBR4, UniProtKB:Q8N4T8). While human CBR4 (the beta subunit of the mammalian heterotetrameric mitochondrial KAR complex with HSD17B8) exhibits secondary carbonyl/quinone reductase activity in vitro, fungal Oar2/Oar1 is an NADPH-dependent 3-oxoacyl-[ACP] reductase dedicated to mitochondrial type II fatty acid synthesis (mtFAS) with no evidence of quinone binding, matching the MARK_AS_OVER_ANNOTATED judgment on S. cerevisiae OAR1.