Question

What is ‘ubiquitination’ and what is it used for in cells?

Answer 1

Ubiquitination is a process through which ubiquitin molecules are attached to protein substrates for protein degradation. Unwanted proteins (misfolded, mutated, or chemically damaged proteins) are removed from a cell by this process.

Additionally, it is also involved in diverese functions such as antigen presentaion, cell cycle regulation, endocytosis, signal transduction, apoptosis and DNA damage repair transcription regulation. Defects in ubiquitin-dependent proteolysis have been shown to result in a variety of human diseases, including cancer, neurodegenerative diseases, and metabolic disorders.

Mechanisms of ubiquitination: Initially, enzyme E1 activates ubiquitin (Ub); then, active Ub is transferred to an E2-conjugating enzyme; finally, E3 Ub ligase attaches Ub to lysine residues on the protein that is targeted for degradation.