POT1 (FOX3/POX3, YIL160C; UniProt P27796) notes
Identity and activity
- Peroxisomal 3-ketoacyl-CoA thiolase, EC 2.3.1.16, last step of the peroxisomal beta-oxidation cycle [UniProt:P27796 "Responsible for the thiolytic cleavage of straight chain 3-"].
- Purified from S. cerevisiae as a homodimer of 45 kDa subunits; peroxisomal location by subcellular fractionation and immunogold PMID:7754706.
- Purified ScFox3 shows thiolase activity PMID:19470242. Same paper reports antifungal activity of the purified protein (in vitro; physiological relevance unclear).
Beta-oxidation role
- fox3 deletion changes the polyhydroxyalkanoate (PHA) monomer profile, consistent with a block at the thiolase step PMID:12819196.
Targeting
- N-terminal PTS2 (aa 1-16) necessary and sufficient for peroxisomal targeting PMID:8125978.
- PTS2 is bound by the PEX7 receptor together with PEX21/PEX18 co-receptors; crystal structure of the Pex7p-Pex21p-PTS2(thiolase) complex PMID:23812376; Y2H with Pex18p/Pex21p PMID:9864360. These "protein binding" IPIs reflect import-cargo recognition, not enzyme function.
- Also detected in the mitochondrial IMS proteome (Vogtle et al. 2012, PMID:22984289) - minor/secondary location, physiological meaning unknown.
Other
- mRNA binding: Pot1p identified in an RNA-binding protein screen; associated mRNAs enriched for translation GO terms PMID:21124907. Moonlighting, not established functionally.
- IBA phenylacetate catabolic process: donor E. coli PaaJ (P0C7L2, 3-oxoadipyl-CoA thiolase). S. cerevisiae has no Paa ring-cleavage pathway; this is node over-propagation.
- YeastPathways RCA places the FAO pathway in cytosol; yeast beta-oxidation is exclusively peroxisomal -> cytosol RCA is wrong.