Anti-Linear Ubiquitin Antibody, clone LUB9 clone LUB9, from mouse

Ubiquitin functions as a marker to indicate the fate of other proteins in the cell. It can be attached as a single molecule or as a polyubiquitin chain. Although ubiquitinated proteins are oftentimes tagged for degradation by the 20S proteosome, ubiquitination can also indicate alternative fates depending on the lysine residue that is involved in linking the ubiquitin chain to the target protein. Ubiquitin chains linked by Lys33 to kinase substrates such as AMP-activated protein kinases, (AMPKalpha1, BRSK1, MARK3, MARK4, and NUAK1), may activate or deactivate these proteins, supporting the role for uniquitin in regulating signaling.