GLUT4 activation: thoughts on possible mechanisms
Bibliographic record
Abstract
A family of facilitative glucose transporters or GLUTs mediates glucose uptake by cells and tissues. The glucose transporter isoform GLUT4, which is the predominant isoform expressed in mature muscle and fat tissues, is primarily responsible for the increase in glucose uptake in response to insulin stimulation. Recent work in our laboratory suggests that there are two divergent responses initiated by insulin stimulation. The first response involves the recruitment of GLUT4 transporters from intracellular reserves and their subsequent insertion into the plasma membrane. The second pathway results in an increase in the intrinsic activity of the transporters. This review will discuss evidence supporting the divergence of the two pathways regulating glucose uptake and, in particular, evidence for the increased intrinsic activity of GLUT4 in response to insulin stimulation. Inhibitors of p38 mitogen-activated protein kinase (MAPK) affected only the arm leading to the insulin-stimulated activation of GLUT4. This implicates p38 MAPK involvement in the regulation of this pathway. There is further evidence that p38 MAPK is itself recruited to the plasma membrane. The role of the phosphorylation state of the glucose transporter in response to insulin stimulation has been studied and indicates that, contrary to what might be predicted, there is actually a decrease in its phosphorylation at the plasma membrane in response to insulin. The relationship of this change to glucose uptake remains to be established. Other possible mechanisms regulating GLUT4 activity include binding of (+) or (-) modulators of its function.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 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".