Novel Splice Variants of Rat CaV2.1 That Lack Much of the Synaptic Protein Interaction Site Are Expressed in Neuroendocrine Cells
Bibliographic record
Abstract
Voltage-gated Ca(2+) channels are responsible for the activation of the Ca(2+) influx that triggers exocytotic secretion. The synaptic protein interaction (synprint) site found in the II-III loop of Ca(V)2.1 and Ca(V)2.2 mediates a physical association with synaptic proteins that may be crucial for fast neurotransmission and axonal targeting. We report here the use of nested PCR to identify two novel splice variants of rat Ca(V)2.1 that lack much of the synprint site. Furthermore, we compare immunofluorescence data derived from antibodies directed against sequences in the Ca(V)2.1 synprint site and carboxyl terminus to show that channel variants lacking a portion of the synprint site are expressed in two types of neuroendocrine cells. Immunofluorescence data also suggest that such variants are properly targeted to neuroendocrine terminals. When expressed in a mammalian cell line, both splice variants yielded Ca(2+) currents, but the variant containing the larger of the two deletions displayed a reduced current density and a marked shift in the voltage dependence of inactivation. These results have important implications for Ca(V)2.1 function and for the mechanisms of Ca(V)2.1 targeting in neurons and neuroendocrine cells.
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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 | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".