TAP transcription and phosphatidylinositol linkage mutants are defective in activation through the T cell receptor
View abstract on PubMed
Summary
This summary is machine-generated.This study reveals that the phosphatidylinositol-anchored protein TAP is crucial for T lymphocyte activation. Defects in TAP transcription or its anchoring mechanism impair T cell receptor signaling and activation.
Area Of Science
- Immunology
- Molecular Biology
- Cell Biology
Background
- The T cell receptor (TCR) complex, along with CD3, mediates T lymphocyte activation.
- Phosphatidylinositol-anchored proteins are cell-surface glycoproteins with roles in cellular signaling.
- The precise function of TAP, a phosphatidylinositol-anchored protein, in T lymphocyte activation remains to be fully elucidated.
Purpose Of The Study
- To investigate the relationship between the TAP protein and T cell receptor/CD3-mediated activation in murine T lymphocytes.
- To characterize the functional consequences of defects in TAP expression and phosphatidylinositol-anchoring.
Main Methods
- Generation of TAP expression mutants from a T-T hybridoma cell line.
- Analysis of distinct mutant classes with defects in TAP transcription or phosphatidylinositol-protein linkage biosynthesis.
- Assessment of antigen-stimulated, TCR-mediated activation in mutant T cells.
- Evaluation of T cell responsiveness to pharmacologic agents mimicking receptor signals.
- Enzymatic removal of phosphatidylinositol-linked proteins from normal T lymphocytes.
Main Results
- Two distinct mutant classes were identified: one with a transcription defect in TAP, and another with a defect in phosphatidylinositol-protein linkage biosynthesis.
- Both mutant classes exhibited impaired antigen-stimulated, TCR-mediated activation of the T-T hybridoma.
- Mutant T cells retained intact immune effector gene programs, responding to receptor-mimicking pharmacologic agents.
- Normal T lymphocytes showed similar defects in responsiveness after enzymatic removal of phosphatidylinositol-linked proteins.
Conclusions
- Phosphatidylinositol-linked cell-surface glycoproteins, including TAP, play a significant role in physiological T cell activation.
- The integrity of the phosphatidylinositol anchor is essential for proper T lymphocyte activation mediated by the T cell receptor.
- These findings highlight the importance of specific membrane protein anchoring mechanisms in immune cell signaling pathways.