ERG9 is the C. albicans member of the canonical fungal squalene synthase lineage. The local
UniProt record places A0A1D8PI71 in PANTHER:PTHR11626:SF2 (SQUALENE SYNTHASE), and the
PTHR11626 family review treats SF2 as the active squalene synthase subfamily while calling
out Arabidopsis SQS2 and Botryococcus SSL members as exceptions outside this canonical
Candida case [file:genes/CANAL/ERG9/ERG9-uniprot.txt, "DR PANTHER; PTHR11626:SF2; SQUALENE SYNTHASE; 1."],
[file:interpro/panther/PTHR11626/PTHR11626-review.yaml, "Squalene synthase activity is conserved in
the single-copy orthologs of fungi, animals and plants, which make up most of SF2."].
Biologically, ERG9 sits at the branch where two molecules of farnesyl diphosphate are
committed to sterol synthesis as squalene. The 2024 fungal sterol-pathway paper is not direct
C. albicans ERG9 enzymology, but it gives a useful modern pathway statement: "farnesyl
pyrophosphate, the last product of the mevalonate pathway, is converted to squalene by
squalene synthase" PMID:39060235.
The GOA-cited Song et al. paper is C. albicans specific but expression-only for this review.
It supports ERG9 belonging to the late sterol response rather than directly proving catalysis
or localization: ERG9 and ERG11 transcripts increased under lovastatin/fluconazole during
mid-logarithmic growth PMID:14653518.
The review remains anchored to the C. albicans SC5314 reference-proteome entry
A0A1D8PI71. A transient 2026-11-06 refetch pulled the older P78589/ERG9_CANAX
entry from strain ATCC 10259 / CBS 5796 instead; that entry is not in the SC5314
reference proteome, lacks CGD locus cross-references, and is not used here as a
machine-readable alternative counterpart.
Newer-literature search:
just deep-research-falcon CANAL ERG9 failed because agentapi is not installed; noERG9-deep-research-falcon.md was created.