Leukocyte-specific protein 1 targets the ERK/MAP kinase scaffold protein KSR and MEK1 and ERK2 to the actin cytoskeleton
Bibliographic record
Abstract
The identification and characterization of scaffold and targeting proteins of the ERK/MAP kinase pathway is important to understand the function and intracellular organization of this pathway. The F-actin binding protein leukocyte-specific protein 1 (LSP1) binds to PKCbetaI and expression of B-LSP1, an LSP1 truncate containing the PKCbetaI binding residues, inhibits anti-IgM-induced translocation of PKCbetaI to the plasma membrane and anti-IgM-induced activation of ERK2. To understand the role of LSP1 in the regulation of PKCbetaI-dependent ERK2 activation, we investigated whether LSP1 interacts with ERK/MAP kinase pathway components and targets these proteins to the actin cytoskeleton. We show that LSP1 associates with the ERK scaffold protein KSR and with MEK1 and ERK2. LSP1-associated MEK1 is activated by anti-IgM treatment and this activation is inhibited by expression of B-LSP1, suggesting that the activation of LSP1-associated MEK1 is PKCbetaI dependent. Confocal microscopy showed that LSP1 targets KSR, MEK1 and ERK2 to peripheral actin filaments. Thus our data show that LSP1 is a cytoskeletal targeting protein for the ERK/MAP kinase pathway and support a model in which MEK1 and ERK2 are organized in a cytoskeletal signaling complex together with KSR, PKCbetaI and LSP1 and are activated by anti-IgM in a PKCbetaI-dependent manner.
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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".