PathScan^® RP Phospho-Tau (Thr231) Sandwich ELISA Kit #45760

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).

It has been shown that phosphorylation of tau at Thr231/Ser235 is elevated in AD brain and human tau-transgenic mouse models of AD, where it may be involved in increasing tau seeding efficiency (4,5). Tau phosphorylation at Thr231 can be detected in cerebrospinal fluid and plasma and shows potential as a biomarker of neurofibrillary pathology in AD (6,7).