BACE1 and Alzheimer disease: The cyclin-dependent kinase 5 (CDK5) has been implicated in AD pathogenesis and plays a critical role in BACE1 regulation, at the transcriptional level via STAT3 (Wen et al., 2008) and at the post-translational level via BACE1 phosphorylation (Song et al., 2015; Allnutt et al., 2020; Requejo-Aguilar, 2023).