ERG9 notes (P29704, YHR190W)

• Function: squalene synthase, 2 FPP + NAD(P)H -> squalene via PSPP, EC 2.5.1.21 [UniProt:P29704]; PMID:8157649.
• Recombinant truncated soluble enzyme active, monomeric, Mg2+/NADPH PMID:8323279.
• Cloning by complementation of erg9-1; activity in E. coli; C-terminal hydrophobic anchor, ER integration PMID:1807826.
• Microsomal enzyme requiring phospholipid PMID:350878.
• Enriched in plasma-membrane-associated ER PMID:11298754 (not in GOA for ERG9).
• YeastPathways splits the reaction into EC 2.5.1.103 (FPP -> PSPP) + PSPP -> squalene; both halves are Erg9; GO:0051996 covers the overall reaction.
• Mito / MOM proteomics hits and Erg26 protein-binding rows: over-annotation / REMOVE.
• Decisions: 22 ACCEPT, 6 MODIFY, 3 KEEP_AS_NON_CORE, 2 MARK_AS_OVER_ANNOTATED, 2 REMOVE (protein binding).