Inhibitor-2 induced M-phase arrest in Xenopus cycling egg extracts is dependent on MAPK activation
Bibliographic record
Abstract
The evolutionarily-conserved protein phosphatase 1 (PP1) plays a central role in dephosphorylation of phosphoproteins during the M phase of the cell cycle. We demonstrate here that the PP1 inhibitor inhibitor-2 protein (Inh-2) induces an M-phase arrest in Xenopus cycling egg extracts. Interestingly, the characteristics of this M-phase arrest are similar to those of mitogen-activated protein kinase (p42MAPK)-induced M-phase arrest. This prompted us to investigate whether Inh-2-induced M-phase arrest was dependent on activation of the p42MAPK pathway. We demonstrate here that MAPK activity is required for Inh-2-induced M-phase arrest, as inhibition of MAPK by PD98059 allowed cycling extracts to exit M phase, despite the presence of Inh-2. We next investigated whether Inh-2 phosphorylation by the MAPK pathway was required to induce an M-phase arrest. We discovered that while p90Rsk (a MAPK protein required for M-phase arrest) is able to phosphorylate Inh-2, this phosphorylation is not required for Inh-2 function. Overall, our results suggest a novel mechanism linking p42MAPK and PP1 pathways during M phase of the cell cycle.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.002 | 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".