PHF1 and tauopathy: Next, we examined the trypsin-resistant tau bands from various tauopathy brains, including AD, PiD, CBD, PSP, a combination case of CBD and PSP (CBD + PSP), and MAPT, by means of 1.0 mg/mL trypsin treatment followed by immunoblotting with TauC4, AT180, 12E8, PHF1, pS409 and AP422 (Fig. 2).