GPR3 and Alzheimer disease: Although it remains to be determined whether other AD-implicated GPCRs (i.e., ADRBs, GPR3, AT2R, and CXCR2) (Bakshi et al, 2008; Thathiah et al, 2009; AbdAlla et al, 2009a, 2009b) require β-arrestin1 and/or β-arrestin2 for their pathogenic activities, these initial observations led us to examine brains of FTLD-tau patients for alterations in β-arrestin1 levels.