Membrane lipid order of sub-synaptic T cell vesicles correlates with their dynamics and function

Area of Science:

• Immunology
• Cell Biology
• Biophysics

Background:

• T cells interact with antigen-presenting cells at the immunological synapse.
• Sub-synaptic vesicles traffic signaling molecules within this synapse.
• The biophysical properties of these vesicles are not fully understood.

Purpose of the Study:

• To investigate the diversity of membrane lipid order in sub-synaptic vesicles.
• To determine the relationship between vesicle membrane order and dynamics.
• To identify how signaling molecules are sorted into specific vesicle populations.

Main Methods:

• Live-cell imaging using multi-spectral TIRF microscopy.
• Utilizing the dye di-4-ANEPPDHQ to measure membrane lipid order.
• Employing vesicle tracking and small molecule drugs to perturb cytoskeletal dynamics.

Main Results:

• Sub-synaptic vesicles exhibit heterogeneous membrane lipid order profiles.
• Vesicle membrane order correlates with their dynamic behavior.
• Linker for Activation of T cells (LAT) is enriched in vesicles with higher membrane order.

Conclusions:

• Membrane lipid order is a key characteristic differentiating sub-synaptic vesicle populations.
• Vesicle lipid order may regulate the sorting and trafficking of signaling molecules.
• This mechanism could be crucial for immunological synapse function and other cellular processes.