Tdh (CG5955, Q9VPE8) notes

2026-10-09 review session

• Deep research (falcon, with perplexity-lite fallback) timed out / failed; no deep-research file.
• UniProt: mitochondrial L-threonine 3-dehydrogenase, EC 1.1.1.103, "glycine from L-threonine: step 1/2"
  [file:DROME/Tdh/Tdh-uniprot.txt "glycine from L-threonine: step 1/2."].
• Ki & Lim 2019: hypomorphic CG5955 allele raises threonine and increases sleep drive
  PMID:31313987;
  PMID:31313987. Authors note indirect effects
  possible.
• Livelo et al. 2023: CG5955 upregulated by time-restricted feeding; IFM knockdown causes muscle
  dysfunction and lipid accumulation
  PMID:36810287.

Decisions

• All 8 annotations accepted (MF 1.1.1.103, threonine catabolism, glycine biosynthesis step 1,
  mitochondrion). Sleep/muscle phenotypes not proposed as GO processes (downstream effects).

Cross-reference

• Gcat deep research cites a 2026 fat-body study in which Tdh knockdown reduced threonine-derived isotope
  incorporation into glycine and serine (see genes/DROME/Gcat/Gcat-deep-research-falcon.md), further
  supporting Tdh as step 1 of glycine formation from threonine. Not yet cached as a publication.