PA5291 encodes BetT3, one of three betaine/carnitine/choline transporter (BCCT, TC 2.A.15) family secondary transporters of Pseudomonas aeruginosa. It is a multi-pass cytoplasmic membrane protein with twelve predicted transmembrane helices and a long C-terminal tail, a feature linked to osmoregulation in related BCCTs. BetT3 transports choline: the PAO1 gene restores choline uptake to a choline transport-deficient Pseudomonas syringae strain, and a betT3 deletion lowers choline uptake by about 80% in choline-induced P. aeruginosa. Expression is induced by choline and repressed by BetI. BetT3 alone can support growth on choline as a carbon source, acts with BetT1 in early uptake after transfer to choline, and is the main choline transporter at high osmolarity, where choline is converted to the osmoprotectant glycine betaine.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005275 amine transmembrane transporter activity | IDA PMID:18156257 Pseudomonas syringae BetT is a low-affinity choline transpor... | MODIFY | Summary: PseudoCAP IDA seed of PTN001247333 from heterologous complementation in P. syringae. Reason: BetT3 (= PA5291) restores choline uptake in a choline transport-deficient P. syringae strain. Choline is a quaternary ammonium compound and GO places its transport outside amine transport, so the specific term is GO:0015220. Seed verdict SOUND for the node term. Proposed replacements: choline transmembrane transporter activity Supporting Evidence: PMID:18156257 Functional P. putida and P. aeruginosa transporters were identified file:PSEAE/PA5291/PA5291-notes.md We previously showed that BetT2 and BetT3 transport GB and choline, respectively file:PSEAE/PA5291/PA5291-bioinformatics/RESULTS.md PA14_69850 BetT3 is identical to PAO1 |
| GO:0015653 glycine betaine:proton symporter activity | IDA PMID:18156257 Pseudomonas syringae BetT is a low-affinity choline transpor... | UNDECIDED | Summary: PseudoCAP IDA glycine betaine:proton symport from the 2008 P. syringae paper. Reason: The 2008 full text could not be read. The same group later summarised it as showing that BetT2 transports glycine betaine and BetT3 transports choline, and BetT2 is PA3933 while BetT3 is PA5291. The row therefore most likely belongs to PA3933. Not removed, because the full text might also report glycine betaine uptake by BetT3. Supporting Evidence: file:PSEAE/PA5291/PA5291-notes.md We previously showed that BetT2 and BetT3 transport GB and choline, respectively file:PSEAE/PA5291/PA5291-bioinformatics/RESULTS.md PA14_12990 BetT2 is identical to PAO1 PA3933 |
| GO:0031460 glycine betaine transport | IDA PMID:18156257 Pseudomonas syringae BetT is a low-affinity choline transpor... | UNDECIDED | Summary: PseudoCAP IDA glycine betaine transport from the 2008 P. syringae paper. Reason: As for the GO:0015653 row; most likely BetT2 (PA3933) data. Supporting Evidence: file:PSEAE/PA5291/PA5291-notes.md We previously showed that BetT2 and BetT3 transport GB and choline, respectively |
| GO:0071475 cellular hyperosmotic salinity response | IDA PMID:18156257 Pseudomonas syringae BetT is a low-affinity choline transpor... | KEEP AS NON CORE | Summary: PseudoCAP IDA hyperosmotic salinity response from osmoprotection in P. syringae. Reason: BetT3 conferred osmoprotection when expressed in P. syringae at high salt, and in P. aeruginosa it is the main choline transporter at high osmolarity, supplying choline for glycine betaine synthesis. A real but secondary role of the transporter. Supporting Evidence: file:PSEAE/PA5291/PA5291-notes.md confer osmoprotection when expressed in P. syringae in a hyperosmolar environment PMID:21478341 BetT3 was the major choline transporter under hyperosmolar conditions |
| GO:0022857 transmembrane transporter activity | IBA GO_REF:0000033 | MODIFY | Summary: PAINT transmembrane transporter IBD at the BCCT family node PTN001247333. Reason: The family-level term is correct and substrate-neutral by design. For BetT3 the substrate is choline, so the row is refined to GO:0015220. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN001247333 · PTN001247333 SUPPORTS TRANSFER BCCT family node; seeds carry different quaternary ammonium substrates, so the node correctly stops at transmembrane transporter activity. Stands on E. coli BetT and CaiT and on BetT1 and BetT3. UniProtKB:Q9HX83 · PA3933 BetT2 SOURCE BAD Its seed row (GO:0005275 from PMID:21478341) describes BetT3, not BetT2; the node does not depend on it. Proposed replacements: choline transmembrane transporter activity Supporting Evidence: file:PSEAE/PA5291/PA5291-notes.md We previously showed that BetT2 and BetT3 transport GB and choline, respectively PMID:21478341 BetT3 was the major choline transporter under hyperosmolar conditions |
| GO:0022857 transmembrane transporter activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO transmembrane transporter activity from IPR000060 (BCCT). Reason: As for the IBA row; refined to choline transmembrane transporter activity. Proposed replacements: choline transmembrane transporter activity Supporting Evidence: file:PSEAE/PA5291/PA5291-uniprot.txt TIGR00842; bcct PMID:21478341 BetT3 was the major choline transporter under hyperosmolar conditions |
| GO:0015837 amine transport | IEA GO_REF:0000108 | MODIFY | Summary: Inferred from the amine transmembrane transporter IDA. Reason: Follows the MF row; the substrate is choline. Proposed replacements: choline transport Supporting Evidence: PMID:21478341 BetT3 was the major choline transporter under hyperosmolar conditions |
| GO:0055085 transmembrane transport | IEA GO_REF:0000108 | KEEP AS NON CORE | Summary: Inferred from transmembrane transporter activity. Reason: True and as precise as GO allows for the process: the substrate is choline, but GO:0015871 choline transport is not a descendant of GO:0055085 (checked in go-basic.obo and QuickGO, 2026-11-06), so replacing this row with it would drop the transmembrane claim, and GO has no choline transmembrane transport process term. The substrate axis is carried by the GO:0015837 row in this review, which is refined to GO:0015871. Kept as non-core rather than refined. Supporting Evidence: PMID:21478341 BetT3 was the major choline transporter under hyperosmolar conditions |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: IBA plasma membrane from the BCCT node, seeded by E. coli BCCTs. Reason: BCCT transporters are multi-pass cytoplasmic membrane proteins; BetT3 has twelve predicted TM helices and imports choline. Supporting Evidence: file:PSEAE/PA5291/PA5291-uniprot.txt TIGR00842; bcct |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular location mapping (cell membrane). Reason: Agrees with the BCCT family location and the uptake activity. Supporting Evidence: file:PSEAE/PA5291/PA5291-uniprot.txt TIGR00842; bcct |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO membrane from IPR000060. Reason: True but general; the cytoplasmic (plasma) membrane is accepted on two rows here. Proposed replacements: plasma membrane Supporting Evidence: file:PSEAE/PA5291/PA5291-uniprot.txt TIGR00842; bcct |
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