AD: decreased localization in hippocampal sections but increased intraneural aggregates in patients (Zhao et al., 2006); translocated from the cytosol to granule intracellular bodies that also stain positive for Rac and Aβ (Ma et al., 2008); increased activity following Aβ42 exposure in hippocampal neurons (Mendoza-Naranjo et al., 2012)HD: PAK1 and PAK2 bind to mutant Htt, PAK1 colocalizes with mutant Htt in human brains (Luo et al., 2008). The gene discussed is PAK2; the disease is Alzheimer disease.