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Early phosphorylation events induced by DPIV/CD26-specific inhibitors
1Centre of Internal Medicine, University of Magdeburg, Magdeburg, Germany.
Cellular Immunology
|October 6, 1998
Summary
Dipeptidyl peptidase IV (DPIV/CD26) inhibitors trigger T cell phosphorylation, impacting T cell activation. This study shows DPIV/CD26
Area of Science:
- Immunology
- Molecular Biology
- Biochemistry
Background:
- Dipeptidyl peptidase IV (DPIV/CD26) regulates T and NK cell activation.
- The role of DPIV/CD26's catalytic activity in T cell costimulation is debated.
Purpose of the Study:
- To investigate the direct involvement of DPIV/CD26 in early phosphorylation events during human T lymphocyte activation.
- To clarify the necessity of DPIV/CD26's enzymatic activity in T cell signaling.
Main Methods:
- Utilized DPIV-specific inhibitors (Lys[Z(NO2)]-thiazolidide and -piperidide).
- Assessed intracellular tyrosine phosphorylation in resting and PMA-stimulated human T cells.
- Examined the interaction between CD26 and tyrosine kinase p56(lck).
Main Results:
- DPIV-specific inhibitors induced intracellular tyrosine phosphorylation in resting T cells.
- These inhibitors decreased PMA-induced tyrosine phosphorylation in a dose-dependent manner.
- DPIV/CD26 inhibition blocked PMA-induced hyperphosphorylation of p56(lck), suggesting a link.
Conclusions:
- DPIV/CD26 directly participates in early T cell activation processes through its enzymatic activity.
- Inhibition of DPIV enzymatic activity generates an inhibitory signal via tyrosine kinases, blocking downstream pathways.
- These findings support DPIV/CD26's role in T cell signal transduction.