YajC is a small single-pass inner-membrane protein in the conserved YajC family. It occurs in SecDF-YajC and bacterial SecYEG-SecDF-YajC-YidC holo-translocon assemblies, while its individual mechanistic contribution to Sec-dependent export remains unresolved.
| GO Term | Evidence | Action | Reason |
|---|---|---|---|
| GO:0005515 protein binding | IPI PMID:18073115 Crystal structure of AcrB in complex with a single transmemb... | REMOVE | Summary: The AcrB co-crystal reports a YajC contact but GO:0005515 is uninformative and the physiological connection is unresolved. Reason: The AcrB contact does not establish a Sec activity or a direct role in multidrug export, and the paper itself could not conclusively attribute the weak phenotype to loss of AcrB-YajC binding. Supporting Evidence: file:ECOLI/YajC/YajC-notes.md The generic protein-binding row should therefore be removed as an uninformative and biologically unsettled interaction record. |
| GO:0005886 plasma membrane | EXP PMID:27435098 Membrane protein insertion and assembly by the bacterial hol... | ACCEPT | Summary: YajC is a single-pass E. coli inner-membrane protein. Reason: Direct YajC purification/topology, HTL work, PAINT, and UniProt subcellular-location mapping all support plasma-membrane localization. Supporting Evidence: PMID:27435098 Here, we show the bacterial holo-translocon (HTL) - a supercomplex of SecYEG-SecDF-YajC-YidC - is a bona fide resident of the Escherichia coli inner membrane |
| GO:0005886 plasma membrane | IBA GO_REF:0000033 | ACCEPT | Summary: YajC is a single-pass E. coli inner-membrane protein. Reason: Direct YajC purification/topology, HTL work, PAINT, and UniProt subcellular-location mapping all support plasma-membrane localization. |
| GO:0005886 plasma membrane | IDA PMID:21235483 Expression, purification and characterization of the Escheri... | ACCEPT | Summary: YajC is a single-pass E. coli inner-membrane protein. Reason: Direct YajC purification/topology, HTL work, PAINT, and UniProt subcellular-location mapping all support plasma-membrane localization. |
| GO:0005886 plasma membrane | IEA GO_REF:0000044 | ACCEPT | Summary: YajC is a single-pass E. coli inner-membrane protein. Reason: Direct YajC purification/topology, HTL work, PAINT, and UniProt subcellular-location mapping all support plasma-membrane localization. |
| GO:0016020 membrane | NAS PMID:8253068 A novel membrane protein involved in protein translocation a... | MODIFY | Summary: YajC is specifically a plasma-membrane Sec accessory subunit. Reason: The generic membrane row is correct but underspecified for a single-pass E. coli inner-membrane component of SecDF-YajC. Proposed replacements: plasma membrane |
| GO:0031522 cell envelope Sec protein transport complex | IPI PMID:27924919 A central cavity within the holo-translocon suggests a mecha... | ACCEPT | Summary: YajC is a SecDF-YajC/holo-translocon component. Reason: Structural and interaction evidence place YajC in the E. coli SecDF-YajC accessory complex and in purified SecYEG-SecDF-YajC-YidC HTL. Supporting Evidence: PMID:27924919 The conserved SecYEG protein-conducting channel and the accessory proteins SecDF-YajC and YidC constitute the bacterial holo-translocon (HTL), capable of protein-secretion and membrane-protein insertion |
| GO:0043952 protein transport by the Sec complex | IDA PMID:24550475 Membrane protein insertion and proton-motive-force-dependent... | KEEP AS NON CORE | Summary: YajC is present in an active purified bacterial Sec holo-translocon. Reason: The HTL evidence supports involvement of the YajC-containing complex in Sec transport, but direct E. coli genetics and follow-up YajC work leave the individual YajC mechanism unresolved, so the core YajC assertion should remain complex membership rather than an independent transport activity. Supporting Evidence: PMID:24550475 SecYEG interacts with the highly conserved YidC and SecDF-YajC subcomplex, which facilitates translocation into and across the membrane file:ECOLI/YajC/YajC-notes.md No independent molecular function should be assigned to YajC from the available evidence. |
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Download this section (compressed HTML)Q: Does YajC make a substrate-specific or assembly-specific contribution to SecDF-YajC/HTL activity in E. coli, or is it dispensable under standard protein-export assays?
Experiment: Compare native HTL abundance, SecDF stability, and substrate-specific export after deleting yajC while monitoring SecD, SecF, YidC, SecYEG, and precursor accumulation.
Hypothesis: YajC tunes SecDF-YajC or HTL assembly for a limited substrate set rather than providing an independent transporter activity.
Type: complex assembly and export phenotyping
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