PIGF (Q07326) review notes

Deep research: falcon was OUT OF CREDITS (HTTP 402); no -deep-research-falcon.md generated.
Review grounded in PIGF-uniprot.txt, the seeded PIGF-goa.tsv, and cached publications/PMID_*.md.

Core biology (verified)

• PIGF is a non-catalytic accessory (stabilizing) subunit of the GPI ethanolamine-phosphate
  transferases PIGO and PIGG. It is NOT an independent enzyme.
• PMID:15632136
• PMID:32156170
• PMID:32156170 (PIGO adds EtNP to Man3, PIGG to Man2; PIGF is the shared stabilizer)
• UniProt: "Stabilizing subunit of the ethanolamine phosphate transferase 3 and ethanolamine phosphate transferase 2 complexes"; "PIGF is required to stabilize PIGG and PIGO".
• Core BP: GPI anchor biosynthetic process (GO:0006506).
• Location: ER membrane (GO:0005789); multi-pass membrane protein (6 TM helices in UniProt features).
• Disease: homozygous p.Pro172Arg causes an inherited GPI-deficiency disorder (OORS / DOORS-overlap).
• PMID:33386993

GOA molecular function

• The seeded GOA TSV carries NO catalytic MF term for PIGF. The only MF line is
  GO:0005515 protein binding (IPI, PMID:32296183 HuRI Y2H). Per instructions I did NOT invent a
  catalytic activity. NOTE: the UniProt DR block lists GO:0051377 mannose-ethanolamine phosphotransferase activity; IBA:GO_Central, but that term is NOT in the GOA TSV, so it was
  intentionally not added as a core_function function.
• core_functions therefore omits function and records BP under directly_involved_in
  (GO:0006506) + location (GO:0005789).

protein binding IPI (PMID:32296183)

• 8 IPI lines to AQP6, GPR152, LYVE1, MANBAL, TIMMDC1, TMEM130, TMEM14B, TMEM86B — all HuRI
  high-throughput Y2H hits to unrelated membrane proteins, none of them PIGO/PIGG.
• Action: MARK_AS_OVER_ANNOTATED (bare uninformative protein binding; not REMOVE per policy).

PANTHER family id

• No PTHR##### family id is present in the UniProt cross-references. The GOA WITH/FROM only
  shows a PANTHER node id PANTHER:PTN009167560 (from the IBA), and UniProt has a PAN-GO line
  but no PANTHER; PTHR##### DR line.

Other identifiers

• InterPro IPR009580 (GPI_biosynthesis_protein_Pig-F); Pfam PF06699 (PIG-F). eggNOG KOG3144.
• Isoforms: Q07326-1 (canonical), Q07326-2 (VSP_004361).