MRP4 transporter is involved in the acquisition of human sperm’s fertilizing ability
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Cyclic AMP (cAMP) regulates multiple aspects of sperm function essential for attaining fertilizing ability; therefore, its intracellular levels must be tightly controlled to ensure proper signaling dynamics. In recent years, multidrug resistance-associated protein 4 (MRP4) has emerged as a novel regulator of cAMP homeostasis by facilitating its efflux. Previous studies from our laboratory have identified MRP4 in mammalian sperm and demonstrated its role in capacitation-associated events in murine and bovine species. However, its relevance in human sperm remains unknown. Our study demonstrates a functional MRP4 in human sperm, as its pharmacological inhibition led to a rapid (5 min) intracellular cAMP accumulation and a subsequent decrease in extracellular levels (30 min) under capacitating conditions, as assessed by radio binding protein assay. At the biological level, MRP4 inhibition resulted in a decrease in tyrosine phosphorylation at 360 min of capacitation. Membrane hyperpolarization was also affected, diminishing the induced acrosome reaction. Moreover, a significant reduction in intracellular Ca2+ levels was observed, leading to a significant decrease in progressive and total motility, as well as an inhibition of hyperactivation. In addition, our results indicated that the decrease in Ca2+ levels was due to impaired CatSper channel activity upon MRP4 inhibition. These findings suggest that MRP4-mediated cAMP efflux is essential for proper sperm function, playing a critical role in maintaining nucleotide homeostasis, which is a key determinant in the regulation of human sperm capacitation.
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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 it