Phospho-Tau (Ser199) Antibody #29957

Tau is a heterogeneous microtubule-associated protein that promotes and stabilizes microtubule assembly, especially in axons. Six isoforms with different amino-terminal inserts and different numbers of tandem repeats near the carboxy terminus have been identified, and tau is hyperphosphorylated at approximately 25 sites by Erk, glycogen synthase kinase-3 (GSK-3), and CDK5 (1,2). Phosphorylation decreases the ability of tau to bind to microtubules. Neurofibrillary tangles are a major hallmark of Alzheimer's disease (AD); these tangles are bundles of paired helical filaments (PHFs) composed of hyperphosphorylated tau. In particular, phosphorylation at Ser396 by GSK-3 or CDK5 destabilizes microtubules. Furthermore, research studies have shown that inclusions of tau are found in a number of other neurodegenerative diseases, collectively known as tauopathies (1,3).

Ser199 of Tau is phosphorylated by various kinases such as GSK-3β, AMP-activated protein kinase (AMPK), and dual specificity tyrosine-phosphorylation-regulated kinase 1A (Dyrk1A) (4-7). Phosphorylation of Ser199 of Tau is an early event in the pathogenesis of Alzheimer's disease (8,9).