TDP-43 is a 414 amino acid (aa) nuclear DNA and RNA-binding protein which regulates transcription and splicing. TDP-43 is aberrantly expressed in most forms of amylotrophic lateral sclerosis and frontotemporal lobar degeneration. In these cases it is absent from the nucleus and accumulates, along with a truncated 25kDa form, in ubiquitin-containing inclusion bodies. In pathological tissues, TDP-43 is highly phosphorylated and Ser409/410 is the main phosphorylation site. Among the TDP-43 protein fragments, the 25kDa fragment is also highly phosphorylated and widely believed to be pathogenic. This antibody is a rabbit polyclonal antibody recognizing TDP-43 only when phosphorylated at 409/410. This antibody detects phosphorylated forms of TDP-43 as well as the cleavage product of 25 kDa.