D14 (AtD14, At3g03990, UniProt Q9SQR3) curation notes

Context: reviewed as part of the strigolactone_signaling_shoot_branching module (D14 receptor ->
SCF(MAX2) -> SMXL6/7/8 degradation -> BRC1). Falcon deep research was attempted but all providers
failed, so these notes are built from cached publications.

Identity

• UniProt Q9SQR3 (D14_ARATH, 267 aa), alpha/beta hydrolase, catalytic triad S97/D218/H247.
• Arabidopsis ortholog of rice D14; paralog KAI2 mediates karrikin responses
  PMID:22357928.

Receptor function

• SL induces open-to-closed transition and D14-D3/MAX2-ASK1 complex
  PMID:27479325.
• Catalytically dead AtD14 D218A still complements atd14 -> intact SL binding may suffice
  PMID:30643123.
• GR24-enhanced interaction with SMXL6/7 (Y2H, co-IP) PMID:26546446.
• Nuclear D14 binds SMXL7 and MAX2 SL-dependently PMID:27317673.

Hydrolase

• Hydrolyses GR24 butenolide; very slow turnover PMID:23381136.
• Hydrolysis deactivates SL after signalling PMID:30643123.

Localisation / feedback

• Nucleus + cytoplasm, overlapping MAX2; local action; SL-induced MAX2-dependent degradation PMID:24610723.

Curation decisions

• GO:1901601 strigolactone biosynthetic process: IBA REMOVE (receptor clade, d14 is SL-insensitive);
  IMP (PMID:22422982) also REMOVE on the same biology. Full text is not open access (Europe PMC: no PMC
  copy; science.org returns 403), so the assay could not be read; the same paper's IMP secondary shoot
  formation row suggests it was a branching phenotype, which reflects SL insensitivity, not biosynthesis.
  D14 does none of the work of SL formation (D27/CCD7/CCD8/MAX1 do), so the term is contradicted
  regardless of evidence code. (Changed from MARK_AS_OVER_ANNOTATED after PR #4383 review.)
• GO:0010223 secondary shoot formation -> MODIFY to GO:2000032 regulation of secondary shoot formation.
• protein binding to SMXLs/MAX2 -> MODIFY to GO:0038023 signaling receptor activity; HT HIPP26 -> REMOVE.
• NEW: GO:0038023 signaling receptor activity; GO:0052689 carboxylic ester hydrolase activity.
• Proposed term: strigolactone receptor activity (child of GO:0038023, analogous to GO:0038198 auxin receptor activity).