Phospho-Tau (Thr217) (E9Y4S) Rabbit mAb #51625

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).

Tau phosphorylation at Thr217 has been identified as a highly specific biomarker of AD. Phosphorylated tau at Thr217 can be detected in cerebrospinal fluid in both preclinical and advanced stages of AD and has been shown to successfully differentiate between AD and non-AD neurodegenerative diseases (4,5).