The Rac1 exchange factor Dock5 is essential for bone resorption by osteoclasts
Bibliographic record
Abstract
Osteoporosis, which results from excessive bone resorption by osteoclasts, is the major cause of morbidity for elder people. Identification of clinically relevant regulators is needed to develop novel therapeutic strategies. Rho GTPases have essential functions in osteoclasts by regulating actin dynamics. This is of particular importance because actin cytoskeleton is essential to generate the sealing zone, an osteoclast-specific structure ultimately mediating bone resorption. Here we report that the atypical Rac1 exchange factor Dock5 is necessary for osteoclast function both in vitro and in vivo. We discovered that establishment of the sealing zone and consequently osteoclast resorbing activity in vitro require Dock5. Mechanistically, our results suggest that osteoclasts lacking Dock5 have impaired adhesion that can be explained by perturbed Rac1 and p130Cas activities. Consistent with these functional assays, we identified a novel small-molecule inhibitor of Dock5 capable of hindering osteoclast resorbing activity. To investigate the in vivo relevance of these findings, we studied Dock5(-/-) mice and found that they have increased trabecular bone mass with normal osteoclast numbers, confirming that Dock5 is essential for bone resorption but not for osteoclast differentiation. Taken together, our findings characterize Dock5 as a regulator of osteoclast function and as a potential novel target to develop antiosteoporotic treatments.
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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".