N: 1. From ubiquit(ous) + -in (‘pertaining to’).
2. Ubiquitin (originally, Ubiquitous Immunopoeitic Polypeptide) was first identified in 1975 as an 8.5 kDa protein of unknown function expressed universally in living cells. Nevertheless, it was first recorded in 1985–90.
3. In biochemistry, ubiquitin is a small polypeptide, found in most eukaryotic cells, that combines with other proteins to make them susceptible to degradation.
4. Ubiquitin consists of only 76 amino acids. It’s appropriately named since it is ubiquitous and is present in virtually all types of cells. It is also one of the most highly conserved (least changed) proteins during evolution. The amino acid sequence of ubiquitin is identical in all creatures from insects to humans.
5. A small but extremely important protein that acts the ‘kiss of death’ to other proteins. Proteins are inactivated by the attachment of ubiquitin to them, a process called ubiquitination. Ubiquitin acts as a tag by which the protein-transport machinery ferries a protein to the proteasome for degradation. Antagonizing this process are enzymes that remove ubiquitin from proteins.
6. In 2004, Aaron Ciechanover and Avram Hershko of the Technion Israel Institute of Technology in Haifa, Israel and Irwin Rose of the University of California, Irvine, USA shared the Nobel Prize in Chemistry ‘for the discovery of ubiquitin-mediated protein degradation’.
7. The most common event is the degradation of the protein via the proteasome. However, it may also affect their activity, location or interactions with other proteins.
Ubiquitin can affect:
- apoptosis (cell death);
- cell division and multiplication;
- degeneration of neurons and muscular cells;
- DNA transcription and repair;
- immune and inflammatory response;
- neural network morphogenesis;
- organelle biogenesis;
- processing of antigens;
- receptor modulation;
- ribosome biogenesis;
- stress response pathway;
- viral infection.
S: 1. Business Dictionary – https://bit.ly/2zq5ooF (last access: 20 November 2018). 2. BIOL – https://bit.ly/2TD8PRc (last access: 20 November 2018); Business Dictionary – https://bit.ly/2zq5ooF (last access: 20 November 2018). 3. CED – https://bit.ly/2QlBlIF (last access: 20 November 2018). 4 to 6. MedicineNet.com – https://bit.ly/2Kp1hxi (last access: 20 November 2018). 7. NMN – https://bit.ly/2xSjAUA (last access: 20 November 2018).