Tau 1N4R (human, recombinant)

Tau is a member of the microtubule-associated protein (MAP) family that facilitates microtubule formation in axons. It is primarily expressed in neurons and localized to axons, but trace amounts have been observed in glial cells and several peripheral tissues, including kidney, lung, and testis. Tau is composed of an N-terminal projection domain that interacts with neurofilaments, cytoplasmic organelles, and neuronal cell membranes and a C-terminal microtubule-binding domain that facilitates microtubule polymerization and stabilization. It is encoded by MAPT in humans, a 16-exon gene that produces six isoforms via alternative mRNA splicing, which differ from each other based on the presence of zero (0N), one (1N), or two (2N) inserts at the amino terminus and the number of microtubule-binding repeat (MTBR) domains at the C-terminus (3R or 4R for three and four repeats, respectively). Tau is subject to post-translational modifications, including phosphorylation, and hyperphosphorylation of tau is associated with the formation of neurofibrillary tangles and neuronal cell death in postmortem brains from patients with Alzheimer's disease. Mutations in MAPT lead to changes in expression of tau isoforms and the formation of insoluble protein aggregates that cause familial frontotemporal dementia (FTD) and parkinsonism linked to chromosome 17 (FTDP-17). Transgenic mice expressing wild-type human tau 1N4R exhibit motor and spatial memory impairments, and postmortem brain levels of insoluble tau 1N4R are increased in patients with Parkinson's disease.. Protein function: Promotes microtubule assembly and stability, and might 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, suggesting that tau functions as a linker protein between both. Axonal polarity is predetermined by TAU/MAPT localization (in the neuronal cell) in the domain of the cell body defined by the centrosome. The short isoforms allow plasticity of the cytoskeleton whereas the longer isoforms may preferentially play a role in its stabilization. [The UniProt Consortium]