IP3R, TRPM6 and Homer1 are Localized to ER‐PM Contact Sites at Tubulobulbar Complexes in Rat Testis
Bibliographic record
Abstract
The seminiferous epithelium is the site of spermatogenesis; the cellular basis for male fertility. Large junction complexes between Sertoli cells act to control the movement of differentiating spermatogenic cells while those between Sertoli cells and late spermatids connect these late spermatids to the apex of the epithelium. During spermatogenesis, turnover of these junction complexes must occur so that the next generation of spermatogenic cells can move into the epithelium, and mature spermatozoa can be released into the seminiferous tubules. Structures called Tubulobulbar Complexes (TBCs) have been implicated in junction turnover due to their appearance during turnover and their necessity in allowing sperm release. TBCs likely drive the internalization of junction complexes but how Sertoli cells control the development and degradation of TBCs is unknown. TBC regulation may be a product of a well‐known yet functionally unestablished contact site between TBC bulbs and cisternae of ER. Because calcium exchange occurs at other ER‐plasma membrane contact sites such as those between ER and endosomes, we chose to probe for the IP3R calcium channel. Using bioinformatics, we found potential protein binding partners for IP3R in the form of the TRPM6 plasma membrane calcium channel and the homer1 scaffolding protein. Using a high‐resolution pre‐embedding immunoelectron microscopy technique we localized all three proteins to the TBC‐ER contact site. This data suggests the potential for scaffolding of IP3R to TRPM6 via homer1 at TBC‐ER contacts and opens up the possibility for calcium exchange as an important function of the ER at these sites. Support or Funding Information Supported by a NSERC Discovery Grant (#155397‐2013) to AWV
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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 | 0.001 | 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".