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Selection of T cell receptor expression mutants through the functionally linked Ly-6A.
E Sugiyama1, A Cantagrel, T Reno
1Medical Services, Massachusetts General Hospital, Harvard Medical School, Boston 02114.
Cellular Immunology
|October 15, 1990
Summary
Ly-6A signaling in T cells requires the T cell receptor/CD3 complex for signal transduction. Mutants lacking TCR/CD3 expression failed to signal via Ly-6A, indicating its central role in T cell activation pathways.
Area of Science:
- Immunology
- Cell Signaling
- Molecular Biology
Background:
- Ly-6A is a GPI-anchored molecule involved in murine T cell activation.
- Anti-Ly-6A antibody stimulation paradoxically inhibits T cell growth, enabling mutant selection.
Purpose of the Study:
- To investigate the signaling pathway of Ly-6A and its relationship with the T cell receptor/CD3 complex.
- To identify T cell mutants selected by anti-Ly-6A antibody and characterize their signaling defects.
Main Methods:
- Mutagenesis and selection of T cell hybridoma subclones.
- Analysis of Ly-6A and T cell receptor/CD3 complex expression.
- Investigation of phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis in response to stimuli.
Main Results:
- Most anti-Ly-6A selected mutants showed reduced Ly-6A responsiveness.
- A significant number of mutants exhibited low or undetectable T cell receptor/CD3 complex expression.
- TCR/CD3-negative mutants failed to hydrolyze PIP2 upon anti-Ly-6A stimulation, but responded to G protein activation.
Conclusions:
- Ly-6A activation signals are transmitted through the TCR/CD3 complex.
- The TCR/CD3 complex is essential for coupling Ly-6A to the G protein/phospholipase C pathway.
- TCR/CD3 complex integrates signals from multiple T cell surface molecules, including Ly-6A, Thy-1, and lectin receptors.