THI3 (YDL080C, Q07471) notes

Evidence journal

• TPP-binding regulator of THI genes PMID:19013460.
• Interacts with Pdc2p PMID:19013460 and Thi2p PMID:16194233; TPP-binding mutants derepress THI genes PMID:16194233.
• No decarboxylase activity PMID:22904058; UniProt CAUTION records the conflict with earlier genetics [UniProt:Q07471].
• Earlier genetics: YDL080C "solely responsible" for alpha-ketoisocaproate decarboxylation PMID:10753893, later attributed to Aro10 PMID:15933030; Thi3p regulatory role PMID:15933030.
• Nucleus (GFP) [UniProt:Q07471].

Curation decisions

• All decarboxylase MF rows (EXP/IEA/RCA), carboxy-lyase, catalytic activity, isoleucine catabolism RCA and cytosol RCA REMOVED (contradicted by direct assay).
• Core: TF binding (Thi2p/Pdc2p coactivator) in positive regulation of thiamine biosynthesis; TPP binding as sensor.
• YeastCyc assignment of THI3 to Ehrlich decarboxylation steps (isoleucine, leucine) is not supported; module curator should drop THI3 from the decarboxylase step or mark it as regulatory only.