Phosphorylation of amyloid-beta at the serine 26 residue by human cdc2 kinase.

The amyloid-beta (Abeta) peptide has been implicated in the pathology of Alzheimer's disease (AD). Using an antisense peptide approach a novel interaction between Abeta and the human cdc2 kinase was identified. The Abeta 1-42, 1-40 and 25-35 peptides were shown to be substrates for the cdc2 kinase and phosphorylated on the Serine 26 residue. Phosphorylated Abeta (pSAbeta) was found in extracts from NT-2 neurons and AD brain. In NT-2 neurons the levels of pSAbeta were increased in the presence of exogenous Abeta and this increase was prevented by a cdc2 protein kinase inhibitor, olomoucine, that also prevented Abeta cytotoxicity. The results from this study suggest that Abeta phosphorylation by cdc2 could play a role in the brain pathology of AD.