Leupaxin is serine phosphorylated and recruited to the immunological synapse upon TCR engagement in cytotoxic T lymphocytes (CTL)
Bibliographic record
Abstract
Abstract Background Leupaxin is a member of paxillin family proteins that function as adaptor proteins in integrin signaling. Compared to other members, leupaxin is mainly expressed in leukocytes. However, the role of leupaxin in T cells is unknown. Results Leupaxin has been shown to be tyrosine phosphorylated in cells including tumor cells, fibroblasts and B cells. However we detected no leupaxin tyrosine phosphorylation in T cells. Instead, leupaxin showed mobility shift in response to TCR signaling. We demonstrated that the mobility shift was caused by serine phosphorylation and was ERK dependent. Although leupaxin is downstream of integrin receptors, LFA-1 stimulation did not induce leupaxin phosphorylation. Several potentially phosphorylated residues were mutated into alanine individually. When Ser54 was mutated, leupaxin no longer showed mobility shift, suggesting that leupaxin is phosphorylated at Ser54. Leupaxin was recruited to the immunological synapse and colocalized with LFA-1. Leupaxin has N-terminal leucine-aspartic acid (LD) domains and C-terminal LIM domains that contain four double zinc finger motifs. The LIM domains were dispensable for leupaxin localization at the contact zone. Leupaxin failed to be recruited to the immunological synapse after deleting LD2–4 domains, suggesting the importance of LD2–4 domains for the recruitment. Conclusions Leupaxin is not tyrosine phosphorylated but serine phosphorylated at Ser54 in response to TCR engagement. Leupaxin is recruited to the immunological synapse through LD2–4 domains. Studies are underway to determine the contribution of leupaxin to CTL adhesion, polarization and degranulation.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 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".