MAPT and Alzheimer disease: We observed that preventing antibody access to intracellular epitopes by omitting the permeabilization step in our ICF protocol resulted in the loss of PAD-exposed tau antibody (TNT1) reactivity in MAPT-KI cultures treated with AD-tau (Fig. 2E), confirming that the PAD-exposed tau inclusions observed in the permeabilized cells (Fig. 2F) were intracellular.