Focal adhesion kinase PTK2 autophosphorylation is not required for the activation of sodium–hydrogen exchange by decreased cell volume in the preimplantation mouse embryo
Bibliographic record
Abstract
SummaryRecovery from decreased cell volume is accomplished by a regulated increase of intracellular osmolarity. The acute response is activation of inorganic ion transport into the cell, the main effector of which is the Na+/H+ exchanger NHE1. NHE1 is rapidly activated by a cell volume decrease in early embryos, but how this occurs is incompletely understood. Elucidating cell volume-regulatory mechanisms in early embryos is important, as it has been shown that their dysregulation results in preimplantation developmental arrest. The kinase JAK2 has a role in volume-mediated NHE1 activation in at least some cells, including 2-cell stage mouse embryos. However, while 2-cell embryos show partial inhibition of NHE1 when JAK2 activity is blocked, NHE1 activation in 1-cell embryos is JAK2-independent, implying a requirement for additional signalling mechanisms. As focal adhesion kinase (FAK aka PTK2) becomes phosphorylated and activated in some cell types in response to decreased cell volume, we sought to determine whether it was involved in NHE1 activation in the early mouse embryo. FAK activity requires initial autophosphorylation of a tyrosine residue, Y397. However, FAK Y397 phosphorylation levels were not increased in either 1- or 2-cell embryos after cell volume was decreased. Furthermore, the selective FAK inhibitor PF-562271 did not affect NHE1 activation at concentrations that essentially eliminated Y397 phosphorylation. Thus, autophosphorylation of FAK Y397 does not appear to be required for NHE1 activation induced by a decrease in cell volume in early mouse embryos.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".