<i>Treponema denticola</i> Msp‐deduced peptide conjugate, P34<sub>BSA</sub>, promotes RhoA‐dependent actin stress fiber formation independent of its internalization by fibroblasts
Bibliographic record
Abstract
P34(BSA), a BSA conjugate of a synthetic 10-mer peptide deduced from Treponema denticola major outer sheath protein (Msp), stabilizes actin filaments in fibroblasts and retards cell motility. We reported previously that it is internalized by cells, binds and bundles actin filaments in vitro, and activates RhoA; yet, its site and mechanism of action were not defined. We have assessed P34(BSA)'s modes of interaction with and signaling to fibroblasts. At 4 degrees C, P34(BSA) was not internalized, but it bound to the plasma membrane and promoted actin stress fiber formation at approximately 80% capacity compared with 37 degrees C controls, casting doubt that cellular uptake is a critical step for its cytoskeleton-stabilizing property. In Rho G-LISA and co-immunoprecipitation assays, P34(BSA) was found to activate RhoA, even at 4 degrees C, to promote its interaction with guanosine nucleotide exchange factor p114RhoGEF. It also caused phosphorylation of cofilin. Upon RhoA inhibition, either by C3 transferase RhoA inhibitor or by transfection with a dominant negative RhoA construct, P34(BSA) did not achieve the stress fiber formation seen with P34(BSA) alone. By inhibiting phosphatidylinositol-3 kinase (PI 3-K) with LY294002, the P34(BSA) effects were completely blocked. Depletion of cholesterol with methyl-beta-cyclodextrin (MbetaCD) partially inhibited P34(BSA) signaling via the plasma membrane to the cytoskeleton. This suggests that multivalent P34(BSA) activation of lipid raft components requires active PI 3-K, and initiates the pathway through a RhoGEF and RhoA, which mediates stress fiber formation in fibroblasts. Hence, P34(BSA) may represent a novel tool to investigate RhoA-dependent processes, such as remodeling filamentous actin in eukaryotic cells.
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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".