title: Cdk5 and munc-18/p67 co-localization in early stage neurofibrillary tangles-bearing neurons in Alzheimer type dementia brains.
abstract: Hyperphosphorylation of tau protein occurs during the formation of paired helical filament (PHF) in the brain with Alzheimer's disease. As previously reported, cyclin-dependent kinase (cdk) 5 can phosphorylate tau at the site of abnormally phosphorylated in PHF. To characterize the relationship between cdk5 and PHF-tau, we investigated the localization of cdk5 and its regulator, p67 (munc 18), in the hippocampus and temporal lobes from 12 Alzheimer type dementia (ATD) patients and 5 controls using immunohistochemical procedures. The specificity of antibodies was confirmed with Western blot analysis. Anti-cdk5 antibody diffusely stained the perikarya of some tau2-positive or neurofibrillary tangle (NFT)-bearing neurons in ATD brains, while cdk5-positive staining was scarcely found in control brains. Anti-p67 antibody also showed stronger immunoreactivity of pyramidal neurons in ATD brains than in control brains. Double immunostaining with anti-cdk5 and anti-p67 antibodies revealed co-localization of both molecules in some pyramidal neurons. These findings suggest that cdk5 is activated by p67 at the early stage of NFT formation and accelerates NFT formation. In cdk5-positive and p67-negative neurons, cdk5 may be activated by other regulator molecules such as p35. In addition, cdk5-positive reactive astrocytes were found close to cdk5-positive NFT-bearing neurons m ATD brains but not in control brains, suggesting a correlation between NFT and reactive astrocytes.
authors.affiliation: Department of Psychiatry, Yokohama City University School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, Japan. megnot@mb.infoweb.ne.jp
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: E
authors.initials: E
authors.lastname: Iseki
authors.forename: K
authors.initials: K
authors.lastname: Kosaka
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000473:pathology*; D001921:Brain / Q000473:pathology*; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins / Q000032:analysis*; D016874:Neurofibrillary Tangles / Q000473:pathology*; D009474:Neurons / Q000473:pathology*; D013997:Time Factors; D033921:Vesicular Transport Proteins
chemical_list: D051938:Munc18 Proteins; D009419:Nerve Tissue Proteins; C497937:STXBP1 protein, human; D033921:Vesicular Transport Proteins; D051360:Cyclin-Dependent Kinase 5; C495905:CDK5 protein, human; D018844:Cyclin-Dependent Kinases