PA5208 (Q9HTY2) notes

Identity

• UniProt Q9HTY2, unreviewed, 225 aa; locus PA5208, no gene name. Name
  "TIGR00153 family protein" is ProtNLM-generated. Domains: Pfam PF01865
  PhoU_div (DUF47), InterPro IPR018445 Put_Phosphate_transp_reg, IPR038078
  PhoU-like superfamily, NCBIfam TIGR00153, PANTHER PTHR36536 (UPF0111
  protein HI_1603). No TM segment, no signal peptide in the entry.
• Neighbour PA5207 is annotated "Phosphate transporter" (Pit family) in the
  PAO1 UniProt list (.cache/paint/pao1.tsv); TIGR00153/DUF47 proteins are
  commonly encoded next to Pit transporters and described as putative
  Pit-accessory, PhoU-like regulators. No experimental characterisation of
  PA5208 or of any member of the family was found (PubMed search for PA5208,
  TIGR00153, UPF0111, "Pit accessory protein").

Literature

• The only paper is the Overhage et al. 2007 mini-Tn5-lux swarming screen of
  PAO1 (PMID:17158671; full text cached). PA5208 is one of 36
  swarming-deficient insertion mutants
  PMID:17158671, and has a
  growth defect PMID:17158671. Biofilm: most non-flagellar, non-pilus mutants made somewhat less
  biofilm PMID:17158671. The screen
  used a 62 mM phosphate medium; Table 1 records possible polar effects of each
  insertion on downstream genes (the cached text does not include the table
  values), and PA5208 lies next to the Pit transporter gene PA5207.

Participation test

What entity performs swarming? The flagellum, its stators, pili and
rhamnolipid surfactant. PA5208 is a cytoplasmic PhoU-like protein of unknown
activity; a single insertion with a growth defect reduces swarming and biofilm,
which is necessity evidence at most, and possibly a polar or
phosphate-homeostasis effect. Neither row passes the participation test.

Clade check: the PTN002194937 leaves are Coxiella burnetii CBU_0015 (Pit
accessory protein; non-motile), Haemophilus influenzae HI_1603 (non-motile,
no flagellar genes), Shewanella SO_3770, Vibrio cholerae VC_2441 ("phosphate
transport regulator") and PA5208. A flagellum-dependent swarming term cannot
hold for organisms without flagella, so the IBD is wrong for the clade as well
as for the seed.

PseudoCAP IBA-seed assessment

Decisions summary

• REMOVE: swarming IBA (over-propagation to non-motile taxa, unsupported seed).
• MARK_AS_OVER_ANNOTATED: swarming IMP and single-species biofilm formation
  IMP (screen phenotypes), with PSEUDOCAP defects.
• No core function: the molecular activity is unknown (PhoU-like domain,
  putative Pit regulator).

Leaf evidence check (2026-11-06)

Audit of the GO_CENTRAL defect on PTN002194937, which made two claims that
needed separating: that the family is "a putative Pit phosphate transporter
accessory/regulator" (a prediction) and that two leaves are in organisms that
lack flagella (a taxon fact, and the load-bearing one). Leaf membership
confirmed with panther_tree.py node PTN002194937 --leaves: 5 leaves, all
PTHR36536:SF3.

Family description, marked as predicted. All five leaves match Pfam
PF01865 PhoU_div, NCBIfam TIGR00153 and InterPro IPR018445, whose own name
is "putative phosphate transport regulator". No leaf has any experimental
annotation, and two of the five "phosphate" names are a submitter SubName and
a ProtNLM name. The entry no longer asserts that the family regulates
phosphate transport; it asserts only that no leaf carries a flagellar
component or motor domain.

Taxon fact, verified. UniProt proteome query (rest.uniprot.org,
2026-11-06) for the six core flagellar structural and motor genes fliF,
flgB, flgE, flhA, fliC, motA:

A free-text flagell* search over the H. influenzae and C. burnetii
proteomes likewise returns no flagellar structural protein. Both organisms are
non-motile. So two of the five leaves cannot perform a flagellum-dependent
process at all.

Confidence raised PROBABLE -> CONFIRMED: the decisive fact is a live resource
query run here, not an inference from a protein name.