Research on Alzheimer’s disease has largely focused on the toxicity and clearance of amyloid-beta. However, the physiological functions of APP (amyloid precursor protein) and other related molecules, which are believed to be the root cause of the disease, remain largely unknown. In this study, a team of four—Matsui, Fujita, Wakana, and Ishita—aims to elucidate the functions of APP and other Alzheimer’s disease-related molecules, deepen our understanding of the disease pathology, and identify new therapeutic targets.