Cytoskeletal actin dynamics shape a ramifying actin network underpinning immunological synapse formation by Fritzsche, M, Fernandes, R, Chang, V, Colin-York, H, Clausen, M, Felce, J, Galiani, S, Erlenkämper, C, Santos, A, Heddleston, J, Pedroza-Pacheco, I, Waithe, D, de la Serna, J, Lagerholm, B, Liu, T, Chew, T, Betzig, E, Davis, S, Eggeling, C