PPIB and Alzheimer disease: In contrast to these findings, MAMs isolated by a Percoll gradient centrifugation from cellular models overexpressing wild type APP or APP harboring familial AD mutations and from brains of double-transgenic AD-mice model, revealed the presence of APP and its catabolites in conjunction with APP-processing active forms of both β- and γ-secretases (Del Prete et al., 2017).