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Intracellular mediators regulate CD2 lateral diffusion and cytoplasmic Ca2+ mobilization upon CD2-mediated T cell
S J Liu1, W C Hahn, B E Bierer
1Department of Biological Chemistry, Dana-Farber Cancer Institute, Boston, Massachusetts.
Biophysical Journal
|February 1, 1995
Summary
T cell activation immobilizes CD2 molecules, a key adhesion protein. Intracellular calcium and microfilaments regulate this process, impacting T cell adhesion strength.
Area of Science:
- Immunology
- Cell Biology
- Biophysics
Background:
- CD2 is a T cell surface glycoprotein crucial for T cell adhesion and activation.
- T cell activation strength is dynamically regulated by CD2-mediated adhesion.
- Lateral redistribution of CD2 and its ligand CD58 (LFA-3) influences cellular adhesion.
Purpose of the Study:
- To investigate the effect of T cell activation on the lateral mobility of CD2.
- To identify intracellular mediators regulating CD2 lateral mobility during T cell activation.
Main Methods:
- Utilized fluorescence photobleaching recovery (FPR) technique.
- Measured lateral mobility of CD2 in plasma membranes of resting and activated Jurkat T leukemia cells.
- Manipulated intracellular calcium levels, cAMP, and microfilament integrity.
Main Results:
- T cell activation resulted in the lateral immobilization of 90% of cell surface CD2 molecules.
- Depletion of cytoplasmic Ca2+, cAMP loading, and microfilament disruption partially reversed CD2 immobilization.
- Intracellular mediators affected CD2 lateral mobility through non-additive, shared signal transduction pathways.
Conclusions:
- Cytoplasmic Ca2+ mobilization, regulated by microfilaments and cAMP, plays a key role in modulating CD2 lateral diffusion.
- This regulation of CD2 mobility likely influences CD2-mediated T cell adhesion strength.
- Understanding these mechanisms provides insights into T cell activation and adhesion dynamics.