Ubiquitin is primarily involved in the regulation of protein degradation within cells. It tags damaged or unnecessary proteins for destruction by the proteasome, a key mechanism in maintaining cellular health. This tagging process, known as ubiquitination, plays a critical role in controlling cell cycle progression, DNA repair, and immune responses.

In research, ubiquitin is used to study protein turnover and signaling pathways. It helps scientists understand diseases linked to protein misfolding and accumulation, such as neurodegenerative disorders including Parkinson's and Alzheimer's disease.

Ubiquitin pathways are also a target for drug development, especially in cancer therapy. Drugs that modulate the ubiquitin-proteasome system, like proteasome inhibitors, are used to treat multiple myeloma and other cancers by disrupting abnormal protein degradation in tumor cells.

Additionally, ubiquitin is used as a tool in biotechnology to purify proteins and study post-translational modifications, offering insights into cellular regulation and potential therapeutic interventions.