A Conformation‐ and Phosphorylation‐Dependent Antibody Recognizing the Paired Helical Filaments of Alzheimer's Disease

Abstract

Hyperphosphorylated tau (PHF‐tau) is the major constituent of paired helical filaments (PHFs) from Alzheimer's disease (AD) brains. This conclusion has been based largely on the creation and characterization of monoclonal antibodies raised against PHFs, which can be classified in three categories: (a) those recognizing unmodified primary sequences of tau, (b) those recognizing phosphorylation‐dependent epitopes on tau, and (c) those recognizing conformation‐dependent epitopes on tau. Recent studies have suggested that the antibodies recognizing primary sequence and phosphorylation‐dependent epitopes on tau are unable to distinguish between normal adult biopsy tau and PHF‐tau. We now present evidence for a new fourth class of monoclonal antibodies recognizing conformation‐dependent phosphoepitopes on tau, typified by TG‐3, a monoclonal antibody raised to PHFs from AD brain homogenates. Studies using a series of deletional tau mutants, site‐directed tau mutants, and synthetic peptides enable the precise epitope mapping of TG‐3. Additional studies demonstrate that TG‐3 reacts with neonatal mouse tau and PHF‐tau but does not recognize adult mouse tau or tau derived from normal human autopsy or biopsy tissue. Further investigation reveals that TG‐3 recognizes a unique conformation of tau found almost exclusively in PHFs from AD brains.

Anesthesia Leads to Tau Hyperphosphorylation through Inhibition of Phosphatase Activity by Hypothermia

“…Our results show that 1 h of anesthesia led to tau hyperphosphorylation at multiple phosphorylation sites found in AD, including pS422 and TG-3, which are considered pathological epitopes (Jicha et al, 1997;Bussiere et al, 1999), and pS199, which is considered an early marker of tau pathology (Maurage et al, 2003). Tau hyperphosphorylation can lead to PHF formation in vitro (Alonso et al, 2001) and is thought to be a critical event in the pathogenesis of AD Avila, 2006).…”

“…The following anti-tau monoclonal antibodies (specificity given in parentheses) were a generous gift from Dr. Peter Davies (Albert Einstein University, New York, NY): TG-3, phospho-Ser231 and conformation specific (Jicha et al, 1997); MC-6, phospho-Ser235 (Jicha et al, 1997); and PHF-1, phospho-Ser396/404 (Otvos et al, 1994). Total tau was detected with either Tau T57120 (monoclonal; BD Transduction Laboratories, San Jose, CA) or Tau A0024 (polyclonal; DakoCytomation, Carpinteria, CA).…”

Tau Potentiates Nerve Growth Factor-induced Mitogen-activated Protein Kinase Signaling and Neurite Initiation without a Requirement for Microtubule Binding

“…Phosphorylation of Tau at Thr-231 is one of the earliest phospho-epitopes to appear in Alzheimer disease (77)(78)(79)(80), and one of several Tau phosphorylation sites thought to "recapitulate" early brain development during neuropathogenesis (81)(82)(83). It will be of interest to determine whether there is a relationship between Tau, A␤ peptide, and the increased levels of AP-1 transcription factors and MAPKs reported in tangle positive neurons (84 -86).…”

Cyr61, a Matricellular Protein, Is Needed for Dendritic Arborization of Hippocampal Neurons

“…Antibodies and Drugs-The mouse anti-Tau (PHF-1) antibody was described previously and kindly provided by Dr. Davies (29). The following antibodies were obtained from commercial sources: rat anti-HA (Roche Applied Science), mouse anti-␣-tubulin, mouse anti-MAP2 (Sigma), rabbit anti-GFP (Medical and Biological Laboratories, Woburn, MA), rabbit anti-phospho-S6 (Ser-235/236), rabbit anti-MAP2 (Cell Signaling Technology, Danvers, MA), mouse anti-␤-galactosidase (Promega, Madison, WI), mouse anti-GAD67 (Millipore, Billerica, MA), mouse anti-Tau (Tau-1) (Cedarlane, Burlington, Canada), hamster anti-CD29 (␤1-integrin chain), and isotype IgM (BD Biosciences).…”