Human Recombinant Phospho-Ubiquitin (Ser65)

Ubiquitin is a small polypeptide that can be conjugated via its C-terminus to amine groups of lysine residue on target proteins. Additional ubiquitin moieties can be subsequently conjugated to this initial ubiquitin, utilizing any one (of seven) lysine residues on the surface of ubiquitin. Phosphorylation was preformed on mutant ubiquitin to facilitate a change on amino acid residue 20 from a serine to a cysteine. The primary function of ubiquitination is to mark proteins for degradation. More specifically, defective mitochondria are selectively degraded after being marked with ubiquitin through a mechanism involving PTEN-induced putative kinase 1 (PINK1) and Parkin. PINK1 is stabilized and accumulates in depolarized mitochondria, where it phosphorylates many proteins. Parkin itself is activated through PINK1-mediated phosphorylated at Ser65 as well as interacting with phosphorylated ubiquitin (also accomplished with PINK1 at Ser65).