Casein kinase 1 delta is associated with pathological accumulation of tau in several neurodegenerative diseases

The distribution of casein kinase 1 δ (Ckiδ) was studied by immunohistochemistry and correlated with other pathological hallmarks in Alzheimer’s disease (AD), Down syndrome (DS), progressive supranuclear palsy (PSP), parkinsonism dementia complex of Guam (PDC), Pick’s disease (PiD), pallido-ponto-nigral degeneration (PPND), Parkinson’s disease (PD), dementia with Lewy bodies (DLB), amyotrophic lateral sclerosis (ALS), and elderly controls. Ckiδ was found to be associated generally with granulovacuolar bodies and tau-containing neurofibrillary tangles in AD, DS, PSP, PDC, PPND, and controls, and Pick bodies and ballooned neurons in PiD. It was not associated with tau-containing inclusions in astroglia and oligodendroglia in PPND, PSP, and PDC. It was also not associated with tau-negative Lewy bodies in PD and DLB, Hirano bodies in PDC, Marinesco bodies in PD, AD, and controls and “skein”-like inclusions in anterior motor neurons in ALS. The colocalization of the kinase Ckiδ and its apparent substrate tau suggests a function for Ckiδ in the abnormal processing of tau.