APP and Mental deterioration: Importantly, in vivo injection of AAV-YAPdeltaC, a neuron-specific YAP isoform, protected against cognitive decline and increased extracellular Aβ and ER instability without changing intracellular Aβ levels in 5xFAD and APP-KI mice [17], demonstrating that YAP is involved in Aβ-induced neurotoxicity and cognitive decline.