CDK5 and Alzheimer disease: DRP-2 has been observed to colocalize with neurofibrillary tangles in the cortex of AD patients (Yoshida et al., 1998) and can be phosphorylated by cyclin-dependent kinase 5 (CDK5), glycogen synthase kinase 3β (GSK3β), Rho kinase, and calmodulin-dependent protein kinase II (CaMKII), which inhibit axonal growth and vesicle trafficking (Gu et al., 2000; Yoshimura et al., 2005; Schmidt and Strittmatter, 2007; Hou et al., 2009).