title: Reduced protein kinase C activity in sporadic Alzheimer's disease fibroblasts.
abstract: A decrease in the protein kinase C immunoreactivity and an altered protein phosphorylation have been reported in patients with Alzheimer's disease, but discordant results have been obtained from determinations of protein kinase C activity. By assaying the calcium- and phospholipid-dependent phosphorylation of a lysine-rich histone after detergent extraction, we have determined the total protein kinase C activity in fibroblasts from patients with sporadic Alzheimer's disease, age-matched controls and young subjects. The activity was not significantly different between young and aged controls, whereas it was significantly lower (0.70 +/- 0.12 vs 1.16 +/- 0.23 nmol/min/mg protein, P less than 0.01) in the patients. The total amount of protein kinase C estimated from the binding of phorbol dibutyrate to intact cells was also significantly lower (1.70 +/- 0.41 vs 2.48 +/- 0.54 pmol/mg protein, P less than 0.01). This decrease in protein kinase C activity suggests that abnormal protein phosphorylation might play a role in the pathogenesis of the disease.
authors.affiliation: Laboratoire de Biochimie Génétique, CNRS URA 1335, Hôpital des Enfants Malades, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Bruel
authors.forename: G
authors.initials: G
authors.lastname: Cherqui
authors.forename: S
authors.initials: S
authors.lastname: Columelli
authors.forename: D
authors.initials: D
authors.lastname: Margelin
authors.forename: M
authors.initials: M
authors.lastname: Roudier
authors.forename: P M
authors.initials: PM
authors.lastname: Sinet
authors.forename: M
authors.initials: M
authors.lastname: Prieur
authors.forename: J L
authors.initials: JL
authors.lastname: Pérignon
authors.forename: J
authors.initials: J
authors.lastname: Delabar
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000201:enzymology*; D002648:Child; D002675:Child, Preschool; D005347:Fibroblasts / Q000201:enzymology*; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D008875:Middle Aged; D015240:Phorbol 12,13-Dibutyrate / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism*
chemical_list: D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C