Characterization of mAb AP422, a novel phosphorylation-dependent monoclonal antibody against tau protein

• Published in: FEBS letters 1996-04, Vol.384 (1), p.25-30
• Main Authors: Hasegawa, M., Jakes, R., Crowther, R.A., Lee, V.M.-Y., Ihara, Y., Goedert, M.
• Format: Article
• Language: English
• Subjects: Alzheimer Disease - metabolism; Alzheimer's disease; Amino Acid Sequence; Animals; Antibodies, Monoclonal; Antibody Specificity; Brain - metabolism; Cerebral Cortex - cytology; Cerebral Cortex - metabolism; Electrophoresis, Polyacrylamide Gel; Humans; Immunoblotting; Immunohistochemistry; MAP kinase; Microscopy, Immunoelectron; Molecular Sequence Data; Mutagenesis, Site-Directed; Phosphopeptides - chemical synthesis; Phosphopeptides - chemistry; Phosphopeptides - immunology; Phosphorylation; Phosphoserine; Rats; Recombinant Proteins - chemistry; Recombinant Proteins - immunology; Recombinant Proteins - metabolism; Tau protein; tau Proteins - analysis; tau Proteins - immunology; tau Proteins - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(96)00271-2

A monoclonal antibody (AP422) specific for phosphoserine 422 in microtubule-associated protein tau has been produced. It strongly labels paired helical filament (PHF) tau from Alzheimer's disease brain in a phosphorylation-dependent manner. By contrast, AP422 only labels a small fraction of fetal tau and a very small fraction of tau from adult brain. The amount of tau phosphorylated at Ser-422 in normal brain is minor relative to that phosphorylated at sites recognized by other phosphorylation-dependent anti-tau antibodies of known epitope. It follows that AP422 is the most specific anti-tau antibody available for detecting the neurofibrillary lesions of Alzheimer's disease. We also show that Ser-422 in tau is a good in vitro substrate for mitogen-activated protein kinase, but not for glycogen synthase kinase-3 or neuronal cdc2-like kinase.