LRRK2 and Parkinson disease: Loss of LRRK2 activity or a PD-linked missense mutation within the RIIβ-binding domain (R1441C) of LRRK2 aberrantly induced a widespread, uncontrolled PKA phosphorylation of cellular substrates, including glutamate ionotropic receptor AMPA type subunit 1 (GluR1; Muda et al., 2014; Parisiadou et al., 2014).