Fig. 4.

Cell polarity complexes polarity at the T cell immunological synapse. Simplified scheme of an immunological synapse between a T cell (in green) and an antigen-presenting cell (in orange). The formation of an immunological synapse starts with the TCR engagement by its cognate antigen displayed on the surface of an antigen-presenting cell. The TCR and CD28 signal transduction drives cytoskeleton reorganization, characterized by the close polarization of the centrosome to the cell contact and the spreading and retraction of a lamellipodium type membrane extension involving active actin polymerization. The various polarity regulators and partner molecules involved are depicted.