Definition:

Ubiquitin is a small protein, consisting of 76 amino acids, found in most eukaryotes. Its main function is to mark proteins that need to be broken down for degradation by the 26S proteasome.Protein ubiquitination and deubiquitination control the initiation, execution, and termination of bulk autophagy as well as ubiquitination involves in signaling certain types of selective autophagy.