Functional Characterization of SM22 during <i>Listeria monocytogenes</i> Infections
Bibliographic record
Abstract
To cause disease, Listeria monocytogenes invades the human intestinal epithelia then spreads to other tissues. Once the bacterium invades host cells, it hijacks the host actin machinery to generate an actin‐rich structure called a comet tail that propels the bacterium within the host cells. When these motile bacteria reach the plasma membrane, these comet tails protrude the membrane forming listeriopods for cell‐to‐cell spreading of the microbes. In our previous work, we identified the 22 kilodalton smooth muscle protein (SM22) as an actin‐associated component of enteropathogenic Escherichia coli pedestals. To further characterize the role of SM22 in bacterial infections, we hypothesized that SM22 would also play a crucial role in the formation and elongation of Listeria ‐induced comet tails. To test this hypothesis, we immunolocalized Listeria ‐infected HeLa cells and found that SM22 localized along the full length of the comet tail. Live imaging of infected cells transfected with fluorescently‐tagged SM22 showed identical results. To study the functional role of SM22 during the infections, we used small interfering RNA (siRNA) to knock‐down SM22 protein levels. In cells with reduced levels of SM22, we observed that the actin cytoskeleton in the host cell remained unchanged, however less comet tails were evident and those that were present appeared shorter in length. Thus, depleting SM22 impairs the formation and elongation of Listeria ‐induced comet tails. Taken together with our previous findings, SM22 is emerging as a general protein hijacked by a variety of gastrointestinal bacteria for their disease processes. Support or Funding Information This study was funded through NSERC.
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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".