TAT and tauopathy: In this context, Tat and TNF-α signaling are linked in several ways: (1) Tat can induce TNF-α production, (2) the cytotoxic effects of Tat and TNF-α are both synergistic and additive, (3) both Tat and TNF-α induce hpTau at residues commonly observed in tauopathy, and (4) Tat and TNF-α impact integrin signaling and increase PINCH levels.