Proteins Involved in the LH Switch Are Present in Detergent-Resistant Membranes of Porcine Granulosa Cells but Not in Cumulus-Oocyte Complexes.
Bibliographic record
Abstract
Lipids rafts are specialized membrane microdomains constituted of sphingolipids, cholesterol and proteins forming platforms that function in membrane signalling and trafficking. Membrane signalling and trafficking are important processes taking place in the ovarian follicle leading to different physiological events such as ovulation. We hypothesized that molecules involved in the Luteinizing Hormone (LH) switch leading to ovulation such as Epidermal Growth Factor (EGF) receptor, progesterone receptor, prostaglandin E2 receptor, Connexin 43 and LH receptor are present in lipid rafts of granulosa cells and cumulus-oocyte complexes (COCs). It is known that lipid rafts can be isolated as detergent-resistant membranes (DRMs) in a cell homogenate. In the present study, two methodological strategies have been used to isolate DRMs present in porcine granulosa cells and COCs from 2-6 mm diameter follicles. In method 1, granulosa cells and COC samples were exposed to Triton X-100 at 4°C and DRMs were isolated by ultracentrifugation of cell extracts in a sucrose density gradient. In method 2, DRMs were isolated by a differential detergent extraction approach. Then, the molecules of interest were detected in the DRMs isolated by method 1 and 2 by Dot Blot assay using specific antibodies. Both methodological strategies allowed the isolation of DRMs as shown by the presence of the ganglioside GM1, a lipid raft marker, in the DRMs isolated by method 1 and 2. However, the results will be discussed based on method 2 (differential detergent extraction) since the contamination of DRMs by membranes from the nucleus and Golgi apparatus is largely decreased in this method. To support the isolation of DRMs, the protein Caveolin-1, a lipid raft marker, was also present in DRMs isolated from both granulosa cells and COCs while the protein Flotillin-1, another lipid raft marker, was only present in granulosa cells. The transferrin receptor, which is known to be cytosolic, was absent in the DRMs isolated from both granulosa cells and COCs, supporting the correct isolation of DRMs.All candidates involved in the LH switch (EGF receptor, progesterone receptor, prostaglandin E2 receptor, Connexin 43 and LH receptor) were present in the DRMs isolated from granulosa cells while only Connexin 43 was present in the DRMs isolated from COCs. In conclusion, DRMs are present in both porcine granulosa cells and COCs. Interestingly, proteins involved in the LH switch are present in lipid rafts of granulosa cells but not in those of COCs suggesting a specific role of lipid rafts as a platform for cell signalling in the ovarian follicle. (poster)
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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 | 0.001 | 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".