Biotinylated M1 (linear) Tetra-Ubiquitin

M1-linked ubiquitination is traditionally associated with regulation of NFĸB and IFN signaling. M1 Tetra-Ubiquitin is a tetrameric chain of wild-type ubiquitin. It is expressed as a linear chain wherein monomers are linked through N-terminal methionines and C-terminal glycines. Increasing evidence suggests that polyUb chains joined through linear peptide bonds between the C-terminus of a ubiquitin and the N-terminus of another play important functional roles. The enzyme machinery responsible for the generation of linear polyUb chains has been termed LUBAC, consisting of HOIL-1L and HOIP. Chains of these type have been determined to have an open conformation, similar to polyUb K63, but with very distinct functional properties. Linear polyUb chains are cleaved by the deubiquitylases CYLD, USP5 (IsoT), USP2 and have been shown to bind to many UBDs including NEMO and Trabin-n (3xnzf).