PGLP1 (PGLP1A; At5g36700; UniProtKB:P0DKC3) curation notes

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are a manual literature summary built only from cached publications in publications/
and the UniProt record (PGLP1-uniprot.txt). No -deep-research-*.md file exists for
this gene.

Identity

• UniProt P0DKC3, "Phosphoglycolate phosphatase 1A, chloroplastic", gene name PGLP1A,
  locus At5g36700; 362 aa precursor, transit peptide 1-54 (proteomics-defined), HAD-like
  hydrolase superfamily, CbbY/CbbZ/Gph/YieH family (UniProt SIMILARITY, InterPro
  IPR006349 PGP_euk, NCBIfam TIGR01452).
• The literature name is PGLP1. A second UniProt entry, P0DKC4 (PGLP1B, At5g36790),
  carries an identical gene model; the original paper notes a genome double annotation in
  this region PMID:17478634. All functional work cited here is on At5g36700.

Molecular function: 2-phosphoglycolate phosphatase (EC 3.1.3.18)

• Recombinant PGLP1 (mature form, without the transit peptide) has PGLP activity
  PMID:17478634.
• Knockout (pglp1-1, SALK_130837) reduces leaf PGLP activity by 97%
  PMID:17478634.
• UniProt curated function and catalytic activity (ECO:0000269 PubMed:17478634):
  "Photorespiratory enzyme that dephosphorylates the 2-phosphoglycolate produced by the
  RuBisCO oxygenation reaction."; Rhea:14369, 2-phosphoglycolate + H2O = glycolate +
  phosphate.
• Enzyme properties (from plant/algal enzymes; review) PMID:17478634.
• Redox regulation: H2O2 sulfenylates PGLP1 at Cys-86 and inhibits it under heat stress
  PMID:38409783.

Biological process: photorespiration (entry step of the C2 cycle)

• PMID:17478634
• Conditional lethality in air, rescued by high CO2 PMID:17478634; the classical EMS
  mutant CS119 carries a missplicing mutation in At5g36700 PMID:17478634.
• Review PMID:22303256 and PMID:22303256.
• The paralog PGLP2 (At5g47760) is active but non-photorespiratory, putatively cytosolic
  PMID:17478634.
• Physiological consequence: 2PG that PGLP1 removes inhibits Calvin-Benson enzymes
  PMID:28947491.
  This is a regulatory consequence of the metabolite, not an additional PGLP1 activity; no
  regulatory process term is proposed.
• Thermotolerance: antisense lines are heat-sensitive and overexpressors more tolerant
  PMID:38409783. This is a downstream
  consequence of 2PG detoxification; I did not propose a "response to heat" annotation.

Location: chloroplast stroma

• Predicted 62-aa transit peptide PMID:17478634; the transit peptide cleavage after Met-54 and
  N-acetylation of Thr-55 were mapped by proteomics (UniProt FT TRANSIT, ECO:0007744
  PubMed:22223895).
• Found in the chloroplast proteome PMID:17478634. Peltier et al. 2006 is the stromal oligomeric proteome (PMID:16207701).
• Mature protein ~34 kDa in vivo after import PMID:38409783.
• TAIR RCA NOT cytosol (PMID:21166475) is consistent: the cytosolic proteome paper set
  aside plastid-targeted proteins.

Annotation decisions (summary)

• MF GO:0008967 (IMP, IEA): ACCEPT, core.
• MF GO:0016791 phosphatase activity (IBA, IEA): MODIFY to GO:0008967.
• CC chloroplast / plastid / stroma HDA rows: ACCEPT (proteomic screens; stroma is the
  precise compartment). Cytoplasm IBA: MODIFY to chloroplast stroma (PAINT node is a mostly
  cytosolic HAD-phosphatase clade; PGLP1 is plastid-targeted).
• BP ND root: MODIFY to GO:0009853 photorespiration (GOA lacks any photorespiration row
  for P0DKC3 although the IMP paper establishes it).
• PANTHER: UniProt places P0DKC3 in PTHR19288:SF46; no PANTHER id is asserted in the
  review.