Like mouse ALK, infection of primary hippocampal neurons with a lentivirus carrying constitutively active ALK.Fc, a chimeric protein in which the extracellular domain of human ALK was replaced by the mouse IgG 2b Fc domain for dimerization [40] (Fig. 1A), dramatically increased accumulation of phosphorylated tau (Fig. 1B, C). Here, MAPT is linked to infection.