Shmt (CG3011, Q9W457) notes

2026-10-09 review session

• Deep research (falcon, with perplexity-lite fallback) timed out / failed; no deep-research file.
• Winkler et al. 2017 (full text cached):
• catalytic requirement: PMID:28515048
• isoforms: PMID:28515048
• localization: PMID:28515048;
  nuclear pool PMID:28515048
• tetramer: PMID:28515048
• Frenkel et al. 2017 (abstract only): glycine synthesis in LNv clock neurons needed for normal period
  PMID:28380364.

Decisions

• Core: GO:0004372 in cytoplasm, mitochondrion, nucleus; glycine biosynthesis, serine catabolism, folate cycle.
• regulation of circadian rhythm (IMP): KEEP_AS_NON_CORE (glycine-supply consequence).
• hydroxytrimethyllysine aldolase (ISS from SHMT1) and carnitine biosynthesis (IC): KEEP_AS_NON_CORE;
  in vitro side activity of mammalian SHMT, untested in insects.

Update: deep research arrived

• Shmt-deep-research-falcon.md (written after the wrapper timed out) agrees with the review.
• Caveat: mitochondrial localization in flies is inferred from the presequence, not shown directly
  [Shmt-deep-research-falcon.md "Mitochondrial localization is inferred from transcript structure and the predicted import sequence, not directly demonstrated by organelle colocalization."].
  The IBA/ISS mitochondrial rows are still accepted as sound inferences.
• Later work (per deep research; not cached): dTTP depletion by cycle 13 in Shmt embryos, and SHMT loss
  promoting genome instability in a Ras tumor model.