Actin cytoskeletal dynamics in T lymphocyte activation and migration

Dynamic rearrangements of the actin cytoskeleton are crucial for the function of numerous cellular elements including T lymphocytes. They are required for migration of T lymphocytes through the body to scan for the presence of antigens, as well as for the formation and stabilization of the immunological synapse at the interface between antigen‐presenting cells and T lymphocytes. Supramolecular activation clusters within the immunological synapse play an important role for the initiation of T cell responses and for the execution of T cell effector functions. In addition to the T cell receptor/CD3 induced actin nucleation via Wasp/Arp2/3‐activation, signals through accessory receptors of the T cell (i.e., costimulation) regulate actin cytoskeletal dynamics. In this regard, the actin‐binding proteins cofilin and L‐plastin represent prominent candidates linking accessory receptor stimulation to the rearrangement of the actin cytoskeleton. Cofilin enhances actin polymerization via its actin‐severing activity, and as a long‐lasting effect, cofilin generates novel actin monomers through F‐actin depolymerization. L‐plastin stabilizes acin filament structures by means of its actin‐bundling activity.