The <i>Klebsiella pneumoniae</i> Gene <i>ytfL</i> Triggers Microtubule Disassembly in Lung Epithelial Cells through KATNAL1
Bibliographic record
Abstract
The Gram‐negative bacterium Klebsiella pneumoniae can cause septicemia, pneumonia, liver abscesses, and meningitis resulting in mortality rates as high as 44%. Unfortunately, the sub‐cellular interactions of these bacteria with host cells remain poorly understood. Because many bacterial pathogens target the host cell cytoskeleton, we examined the host cell cytoskeleton of K. pneumoniae ‐infected lung epithelial cells. In this study, we focused on the host microtubule network and found that microtubules were severed by the microbes, which ultimately led to the disassembly of the entire microtubule network. Because severing of microtubules in lung epithelial cells are regulated by host cell mechanisms, we hypothesized that a K. pneumoniae gene product would trigger the microtubule severing events through the activation of a host microtubule severing protein. To test this hypothesis, we screened the known disease‐causing proteins of K. pneumoniae and found that expression of the capsular polysaccharide, outer membrane porins, and the type VI secretion system were not important for inducing microtubule severing. Next, we constructed and screened a library encompassing essentially all (~3000) K. pneumoniae genes to identify genes that could cause this phenotype. Using this library, we identified the gene KP ytfL that caused the microtubule severing phenotype. To further characterize this novel mechanism, we immunolocalized all known epithelial cell microtubule severing proteins in K. pneumoniae ‐infected cells and found that the katanin‐like protein 1 (KATNAL1) localized precisely to the sites of microtubule severing. Taken together, our study shows that K. pneumoniae exploits a novel strategy to disassemble epithelial cell microtubules during its infections. The disassembly of microtubules is initiated by the expression of the bacterial gene KP ytfL , which ultimately induces the host protein KATNAL1 to sever microtubules and disrupt the microtubule network of host cells. Support or Funding Information This study was funded by NSERC, Taiwan NHRI and SFU Funds.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".