Ubiquitin is a small, 76-amino acid, regulatory protein that was discovered in 1975. It’s present in all eukaryotic cells, directing the movement of important proteins in the cell, participating in both the synthesis of new proteins and the destruction of defective proteins.
Found in all eukaryotic cells with the same amino acid sequence, ubiquitin has been virtually unchanged by evolution. Eukaryotic cells, as opposed to prokaryotic cells, are complex and contain a nucleus and other areas of specialized function, separated by membranes.
Eukaryotic cells make up plants, fungi, and animals, while prokaryotic cells make up simple organisms like bacteria.
The cells in your body build up and break down proteins at a rapid rate. Ubiquitin attaches to proteins, tagging them for disposal. This process is called ubiquitination.
Tagged proteins are taken to proteasomes to be destroyed. Just before the protein enters the proteasome, ubiquitin is disconnected to be used again.
In 2004, the Nobel Prize in Chemistry was awarded to Aaron Ciechanover, Avram Hershko, and Irwin Rose for the discovery of this process, called ubiquitin mediated degradation (proteolysis).
Based on its function, ubiquitin has been studied for a role in potential targeted therapy to treat cancer.
Doctors focus on specific irregularities in the cancer cells that allow them to survive. The goal is to use ubiquitin to manipulate the protein in cancer cells to cause the cancer cell to die.
The study of ubiquitin has led to the development of three proteasome inhibitors approved by the Food and Drug Administration (FDA) to treat people with multiple myeloma, a form of blood cancer:
- bortezomib (Velcade)
- carfilzomib (Kyprolis)
- ixazomib (Ninlaro)
According to the National Cancer Institute, researchers are studying ubiquitin in relationship to normal physiology, cardiovascular disease, cancer, and other disorders. They’re focusing on several aspects of ubiquitin, including:
- regulating the survival and death of cancer cells
- its relationship to stress
- its role at mitochondria and its disease implications
Several recent studies have investigated the use of ubiquitin in cellular medicine:
2017 studysuggested that ubiquitin is also involved in other cellular processes, such as activation of nuclear factor-κB (NF-κB) inflammatory response and DNA damage repair.
2018 studysuggested that dysfunction of the ubiquitin system can lead to neurodegenerative disorders and other human diseases. This study also indicates that the ubiquitin system is involved in the development of inflammatory and autoimmune diseases, such as arthritis and psoriasis.
2016 studysuggested that many viruses, including influenza A (IAV), establish infection by taking over ubiquitination.
However, because of its diverse and complicated nature, the mechanisms behind the physiological and pathophysiological actions of the ubiquitin system aren’t yet fully understood.
Ubiquitin plays an important role in regulating protein on the cellular level. Doctors believe it has promising potential for a variety of targeted cellular medicine treatments.
The study of ubiquitin has already led to the development of medications for the treatment of multiple myeloma, a form of blood cancer. These medications include bortezomib (Velcade), carfilzomib (Kyprolis), and ixazomib (Ninlaro).