MARCKS and Alzheimer disease: Aβ, the main component of senile plaques and the putative toxic species underlying AD pathology, causes MARCKS phosphorylation through PKC and MAPK, as well as MARCKS upregulation, when applied exogenously in cultured neurons and microglia (Hasegawa et al., 2001; Tanimukai et al., 2002; Murphy et al., 2003).