Language
Country/Area
No result found
Why is ubiquitin called the "master key of the cell"? Uncover its mystery!
Ubiquitin is a small intracellular regulatory protein with a molecular weight of approximately 8.6 kDa and is widely present in most eukaryotic tissues. Ubiquitin was first discovered by scientist Christian Goldstein back in 1975, and in the following decades intensive research on its properties made it an important subject of cell biology research. The scientific community describes it as "the master key of cells" because ubiquitin can participate in regulating a variety of biological processes, including but not limited to protein decomposition, changes in internal position of cells, and regulation of their activity.
Ubiquitin can mark proteins, trigger their degradation, change positional information, activate or inhibit activity, thereby affecting cell function.
The role of ubiquitin is mainly manifested through the process of ubiquitylation. Ubiquitination is an enzymatic post-translational modification process in which ubiquitin proteins covalently bind to certain amino acid residues of substrate proteins. This process is generally divided into three main steps: activation, covalent binding and ligation. These steps are respectively responsible for three types of enzymes, namely ubiquitin activating enzyme (E1), ubiquitin covalent conjugating enzyme (E2), and ubiquitin ligase (E3).
The linking process of ubiquitin ultimately forms an isopeptide bond that binds to the lysine residue of the substrate protein to achieve its function.
The structure of ubiquitin contains 76 amino acids and is highly conserved in eukaryotes. The ubiquitin sequences in humans and yeast are 96% identical. There are four genes encoding ubiquitin in the human genome, namely UBB, UBC, UBA52 and RPS27A. The discovery of these genes has given us a deeper understanding of the biological functions of ubiquitin and its role in cell physiology.
Types and functions of ubiquitination
Ubiquitination can be divided into monoubiquitylation and polyubiquitylation. Monubiquitination refers to the attachment of a ubiquitin molecule to a single substrate protein residue, which is critical for regulating cellular processes such as membrane protein trafficking and endocytosis. Polyubiquitination is the formation of ubiquitin chains, usually built on specific lysine residues. This structure plays an important role in protein degradation.
Existing studies indicate that only polyubiquitination at specific lysine residues, such as K48 and K11, is associated with protein degradation by the proteasome.
The content of ubiquitin is not only called the "master key of cells" because of its diverse functions, but also regulates many important processes in cells, such as participating in the cell cycle, gene transcription, DNA repair, and apoptosis. Ubiquitination also plays an important role in antigen processing and regulating immune responses, which is believed to be of great significance to biomedical research.
Relationship between diseases and ubiquitin system
Dysregulation of the ubiquitin system is closely related to the pathogenesis of various diseases. This includes neurodegenerative diseases, cancer and immune diseases, among others. For example, in Alzheimer's disease, the accumulation of ubiquitin may promote the incorrect aggregation of specific proteins within cells, thereby accelerating the development of the pathological process. Given the multiple functions of ubiquitin within cells, further research on this system will help explore new therapies and treatments.
As scientists gain a deeper understanding of ubiquitin and its effects, treatments targeting the ubiquitination pathway may be developed in the future, thereby impacting the prevention and efficacy of many diseases. As research continues, will we be able to understand the multiple roles of ubiquitin in disease?
