PA1057 (Q9I4R7, ShaE) notes

2026-10-28 review (PseudoCAP IBA-seed worklist, rank 26)

No deep-research provider was available; literature collected by PubMed search
and cached abstracts or full texts. The PseudoCAP-cited paper (PMID:16030218,
Kosono et al. 2005) is abstract-only here: its PMC copy (PMC1196046) is a
scanned PDF with no text. The same paper also seeds the subunit C IBD
(see genes/PSEAE/PA1055/PA1055-notes.md).

Identity

UniProt Q9I4R7 (unreviewed), 174 aa, three predicted TM helices (Phobius
12-30, 36-57, 69-88). InterPro IPR002758 Cation_antiport_E; Pfam PF01899
(MNHE); PANTHER PTHR34584:SF1 [file:PSEAE/PA1057/PA1057-uniprot.txt].
Fourth gene of the six-gene sha cluster PA1054-PA1059 (shaABCDEFG with
shaA and shaB fused in Gram-negative Mrp operons PMID:29218041). By gene order and family, PA1057 = ShaE (MrpE); the abstract
names only PA1054 explicitly, so the mapping is an inference.

What PMID:16030218 shows

Whole-cluster complementation of E. coli TO114, lost when PA1054 is deleted
PMID:16030218.
The abstract reports disruption of PA1054 only PMID:16030218. The abstract describes no PA1057 mutant (full text not read).

MrpE in the family

Needed for normal membrane levels of other subunits and for complex
formation in B. pseudofirmus PMID:20624916. MrpE-T113Y abolishes antiport and
complex PMID:29218041.
But in B. subtilis MrpE was reported dispensable for ion transport
PMID:29218041.
Structure: two short TMHs plus a cytoplasmic domain; one model has Na+
entering via MrpE PMID:36241630.

Annotation decisions (summary)

GO:0015385 sodium:proton antiporter activity (IBA, IMP): ACCEPT as the core
activity, but contributes_to; defects for qualifier and IMP code.
GO:0035725 sodium ion transmembrane transport (IBA, IMP): ACCEPT; IMP code
flagged.
GO:0008324 (IEA): MODIFY to GO:0015385; GO:0006812 (IEA): MODIFY to
GO:0035725; GO:0016020 (IEA): MODIFY to GO:0005886; GO:0005886: ACCEPT.

PseudoCAP IBA-seed assessment

PTN node	node term	n_seeds	leaf IBAs	seed annotation (term, evidence, PMID)	verdict	rationale
PTN002160407	GO:0015385 sodium:proton antiporter activity	1 (sole)	20	GO:0015385, IMP, PMID:16030218	INDIRECT-PHENOTYPE	The abstract describes no PA1057 mutant. The evidence is a PA1054 disruption plus whole-cluster complementation of E. coli TO114, which shows the Sha complex is an antiporter. MrpE is an accessory subunit needed for complex assembly in B. pseudofirmus but reported dispensable for transport in B. subtilis. Right as `contributes_to`, not as `enables` + IMP. The LUCA-root node also covers MBH/MBX hydrogenase subunit A proteins (TK2080, TK1226).
PTN002160407	GO:0035725 sodium ion transmembrane transport	1 (sole)	20	GO:0035725, IMP, PMID:16030218	SOUND	As a subunit of the Na+-extruding complex, PA1057 takes part in Na+ transmembrane transport, and MrpE is proposed as the Na+ entry route. The process fits the clade, MBH Na+ modules included. Caveat: IMP looks like the wrong code for PA1057 (no mutant in the abstract); filed as a CHECK.

Audit 2026-10-29: confidence matched to what was read

PMID:16030218 is still abstract-only here: the PubMed MCP returns no body
text (the PMC copy, PMC1196046, is a scanned PDF the publisher does not
release as XML), and the PMC, Europe PMC and ASM pages were not retrievable.
The WRONG_EVIDENCE_CODE (IMP) defects on this gene rest on the abstract not
describing a mutant of this gene, so they are lowered from PROBABLE to
SUSPECTED. The WRONG_QUALIFIER defects (enables vs contributes_to) rest on
positive statements in other Mrp papers and stay PROBABLE. The reference
correctness for PMID:16030218 is changed from MISCITED to UNVERIFIED.
Annotation actions are unchanged.

Full-text check of PMID:16030218 (2026-11-05)

The full text of Kosono et al. 2005 was supplied by the user and read. It
supersedes the earlier notes above that describe this paper as abstract-only.
The only sha mutant the paper constructs is the PA1054 insertion; the
cluster-level evidence comes from expressing the whole PA1054-PA1059 cluster,
or the cluster with PA1054 disrupted, in an antiporter-deficient E. coli
strain. There is no PA1057 mutant, so the IMP evidence-code defects on PA1057 are CONFIRMED.