The enteropathogenic E. coli receptor Tir remains non‐ubiquitylated to enable the bacteria to remain extracellular
Bibliographic record
Abstract
Cells use clathrin‐mediated endocytosis as one strategy to internalize particles from the extracellular compartment. This mechanism of internalization requires the use of a ligand and receptor for the internalization event to occur. Recent work suggests that in order for large particles to enter non‐phagocytic cells their receptors must become ubiquitylated. Ubiquitylation involves the posttranslational modification of a protein by ubiquitin. Enteropathogenic E. coli (EPEC) is an extracellular microbe that injects its own receptor, called the translocated intimin receptor (Tir), into epithelial cells. Surprisingly clathrin‐associated components are recruited to the site of EPEC/host cell contact, but somehow clathrin's internalization function is blocked. We hypothesized that the EPEC receptor Tir remains non‐ubiquitylated to ensure that EPEC remains extracellular. To test this hypothesis we used immunoprecipitations and western blotting of EPEC infected epithelial cells to examine the ubiquitylation status of EPEC Tir and found that it does not become ubiquitylated. To functionally test our hypothesis we forced EPEC Tir to be ubiquitylated by directly fusing ubiquitin to EPEC Tir. This fusion was transfected into epithelial cells and the cells infected with EPEC containing a non‐functional Tir, resulting in the bacteria being internalized. Our work demonstrates that during normal EPEC infections, the blockage of Tir receptor ubiquitylation contributes to EPEC remaining extracellular.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".