Ubiquitination

Ubiquitin is a small protein that is ligated to lysine residues of other proteins, thus signalling an event. The best characterised result of ubiquitination is degradation of the ubiquitinated protein via the proteasomal degradation. Other possible consequences of ubiquitination include endocytosis and regulation of DNA repair. Ubiquitin is the first and best characterised protein of a group of proteins called the ubiquitin like proteins that have a similar fold to ubiquitin and are also ligated to lysine residues of other proteins. The role of ubiquitin and ubiquitin like proteins in many basic cellular processes implicates their dysregulation in many disease states including cancers and neurodegenerative diseases.