Anti-Tau (TauC4 Antibody, 354-369) serum, from rabbit

Microtubule-associated protein tau (UniProt: P10636; also known as Neurofibrillary tangle protein, Paired helical filament-tau, PHF-tau) is encoded by the MAPT (also known as MAPTL, MTBT1, TAU) gene (Gene ID: 4137) in human. Microtubule-associated protein tau is shown to be expressed in neurons. It is mostly found in axons, in the cytosol, and in association with plasma membrane components. Nine isoforms of Tau have been described that are generated by alternative splicing. Tau proteins promote microtubule assembly and stability and may also be involved in the establishment and maintenance of neuronal polarity. The C-terminus binds axonal microtubules while the N-terminus binds neural plasma membrane components, thus serving as a linker protein between both. The short isoforms are reported to allow plasticity of the cytoskeleton whereas the longer isoforms may preferentially play a role in its stabilization. In Alzheimer disease (AD), the neuronal cytoskeleton in the brain is progressively disrupted and replaced by tangles of paired helical filaments (PHF) and straight filaments, mainly composed of hyperphosphorylated forms of Tau. In AD brain Tau accumulates in both the somatodendritic and axonal domains of neurons and it also accumulates in the soma as neurofibrillary tangles (NFTs). Tau oligomers are reported to be neurotoxic when applied extracellularly to cultured neuronal cells and can induce neurodegeneration and synaptic and mitochondrial dysfunction in vivo. It has been reported that most of the C-terminus of Tau (aa 243-406) in PHFs can be cleaved by trypsin, however the TauC4 region is highly resistant to trypsin action. (Ref.: Taniguchi Watanabe, S., et al. (2016). Acta Neuropathol. 131(2); 267-280; Ando K., et al. (2010). Biochem. Soc. Trans. 38(4); 1001-1005).