betT (b0314) encodes the high-affinity choline transporter of Escherichia coli, a secondary carrier of the betaine/choline/carnitine transporter (BCCT) family driven by the proton-motive force. It has 12 transmembrane segments in the cytoplasmic membrane, with a short cytoplasmic N-terminus and a long cytoplasmic C-terminal domain. BetT activity rises about tenfold on hyperosmotic upshock, and C-terminal truncations block this activation. BetT supplies intracellular choline to the BetA-BetB pathway that makes the osmoprotectant glycine betaine. betT is transcribed divergently from betIBA, and both transcripts are induced by osmotic stress and choline.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: PAINT plasma-membrane IBD at the BCCT family node PTN001247333 (seeds include BetT itself). Reason: BetT is a 12-helix inner-membrane protein; topology was determined experimentally. P0ABC9 is one of the node's seeds. Supporting Evidence: PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed PMID:15919996 we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins |
| GO:0005886 plasma membrane | IDA PMID:15919996 Global topology analysis of the Escherichia coli inner membr... | ACCEPT | Summary: Inner-membrane proteome topology analysis included BetT. Reason: Direct reporter-fusion topology mapping of E. coli inner-membrane proteins; consistent with the BetT-specific topology study (PMID:17322201). Supporting Evidence: PMID:15919996 we established the periplasmic or cytoplasmic locations of the C termini for 601 inner membrane proteins PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: UniProt subcellular-location mapping (cell inner membrane, multi-pass). Reason: Agrees with the experimental topology data. Supporting Evidence: PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed |
| GO:0005886 plasma membrane | ISM PMID:1956285 DNA sequence and analysis of the bet genes encoding the osmo... | ACCEPT | Summary: Sequence-model prediction of a multi-pass membrane protein. Reason: Later confirmed by reporter-fusion topology (PMID:17322201). Supporting Evidence: PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline |
| GO:0006974 DNA damage response | IEP PMID:11967071 Over 1000 genes are involved in the DNA damage response of E... | MARK AS OVER ANNOTATED | Summary: betT expression changed after mitomycin C treatment in a genome-wide microarray study. Reason: Nearly 30% of all genes changed expression in this study, and the authors attribute part of the response to general and osmotic stress networks. There is no evidence that choline uptake contributes to DNA-damage responses; the transcript change is a by-product of stress regulation. Supporting Evidence: PMID:11967071 a large number of genes (nearly 30% of all genes) displayed significant changes in their expression level PMID:11967071 we observed the induction of other stress response pathways, such as those of oxidative stress and osmotic protection |
| GO:0015220 choline transmembrane transporter activity | EXP PMID:1956285 DNA sequence and analysis of the bet genes encoding the osmo... | ACCEPT | Summary: BetT is the proton-motive-force-driven, high-affinity choline transport system. Reason: Transport assays with betT clones established high-affinity choline uptake (UniProt curates the kinetics and FCCP sensitivity from this paper), and later mutational work on BetT confirms it is the major choline carrier. Core function. GO has no choline:proton symporter term, so this is the most specific available. Supporting Evidence: PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline PMID:17322201 The major carrier of choline is the high-affinity, proton-driven, secondary transporter BetT, which belongs to the BCCT family of transporters. file:ECOLI/betT/betT-deep-research-openscientist.md The primary function of BetT is transport, not catalysis. |
| GO:0015871 choline transport | EXP PMID:1956285 DNA sequence and analysis of the bet genes encoding the osmo... | ACCEPT | Summary: BetT mediates choline uptake. Reason: Same evidence as the MF row; choline transport is the process BetT performs. Core process. Supporting Evidence: PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline PMID:3512526 Mutants carrying deletions of this region also lacked glycine betaine aldehyde dehydrogenase activity and high-affinity uptake activity for choline |
| GO:0016020 membrane | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO membrane from the BCCT signature IPR000060. Reason: Correct but general; the experimental topology places BetT in the cytoplasmic membrane, and GO:0005886 is accepted on four rows here. Proposed replacements: plasma membrane Supporting Evidence: PMID:17322201 the predictions that BetT comprised 12 membrane-spanning regions and that its N- and C-terminal extensions of about 12 and 180 amino acid residues, respectively, were situated in the cytoplasm were confirmed |
| 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 because the BCCT family carries choline, glycine betaine, carnitine, ectoine and other substrates. For BetT the substrate is established experimentally, so the row is refined to GO:0015220, which this review accepts on EXP evidence. Propagation Review Root cause: TERM SCOPING PROBLEM Failure modes: GRANULARITY MISMATCH Sources checked: PANTHER:PTN001247333 · PTN001247333 SUPPORTS TRANSFER Family-wide BCCT node; seeds transport different quaternary amines, so the node correctly stops at transmembrane transporter activity. Proposed replacements: choline transmembrane transporter activity Supporting Evidence: PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline PMID:17322201 The major carrier of choline is the high-affinity, proton-driven, secondary transporter BetT, which belongs to the BCCT family of transporters. |
| GO:0022857 transmembrane transporter activity | IEA GO_REF:0000002 | MODIFY | Summary: InterPro2GO transmembrane transporter activity from IPR000060. Reason: As for the IBA row: true but general, refined to the experimentally established choline transmembrane transporter activity. Proposed replacements: choline transmembrane transporter activity Supporting Evidence: PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline |
| GO:0055085 transmembrane transport | IEA GO_REF:0000108 | MODIFY | Summary: Inferred from transmembrane transporter activity. Reason: True but general. The transported substrate is choline, so the process is refined to GO:0015871 choline transport, accepted here on EXP evidence. GO has no choline transmembrane transport child of GO:0055085, so this refinement is lateral rather than to a descendant. Proposed replacements: choline transport Supporting Evidence: PMID:1956285 betT encoding a proton-motive-force-driven, high-affinity transport system for choline |
Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)Loading supporting content…
Download this section (compressed HTML)