Dynamics of subsynaptic vesicles and surface microclusters at the immunological synapse

Area of Science:

• Immunology
• Cell Biology
• Molecular Signaling

Background:

• T cell activation relies on signaling hubs at T cell-antigen-presenting cell (APC) interfaces.
• Kinases and adaptor proteins form these signaling centers, crucial for immune responses.

Purpose of the Study:

• To investigate the role of the adaptor protein LAT and its vesicular transport in T cell signaling microcluster formation.
• To elucidate the dynamics of LAT and SLP-76 interactions at the immunological synapse.

Main Methods:

• Utilized advanced imaging techniques to observe protein clustering at T cell-APC interfaces.
• Employed site-directed mutagenesis to study LAT's binding interactions.
• Used laser tweezers for high-resolution imaging of T cell-APC conjugates.

Main Results:

• LAT and SLP-76 formed distinct clusters at the T cell-APC interface.
• LAT-containing vesicles trafficked to SLP-76 microclusters, exhibiting reduced motility and increased phosphorylation.
• Mutating LAT's GADS-binding sites disrupted its localization to SLP-76 clusters.
• Inhibitory receptor ILT2 signaling disrupted SLP-76 microcluster assembly.

Conclusions:

• Vesicular LAT movement is intrinsically linked to the organization of protein microclusters.
• Vesicular LAT plays a significant role in the formation and function of the SLP-76 signalosome.
• These findings offer insights into the regulation of T cell activation signaling pathways.