PathScan ® RP Phospho-Tau (Ser396) Sandwich ELISA Kit

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). 1.Johnson, G.V. and Stoothoff, W.H. (2004) J Cell Sci 117, 5721-9. 2.Hanger, D.P. et al. (1998) J Neurochem 71, 2465-76. 3.Bramblett, G.T. et al. (1993) Neuron 10, 1089-99.