Dysregulated protein secretion and shedding are linked to neurologic and psychiatric diseases, including neurodegeneration, e.g., APP, APOE, SORL1, and TREM2 in Alzheimer's disease (AD), or the prion protein (PRNP) in prion disease (Lichtenthaler et al, 2018). Here, TREM2 is linked to Alzheimer disease.