Proteasome
About Proteasome
The proteasome is the cell's primary mechanism for regulating specific proteins and removing misfolded proteins. Proteins to be degraded are first tagged (or attached) to a small protein called ubiquitin. This labeling reaction is catalyzed by ubiquitin ligase. Once a protein is tagged with a ubiquitin molecule, other ligases are triggered to add more ubiquitin molecules, forming a "polyubiquitin chain" that can bind to the proteasome. This brings the proteasome to the tagged protein to begin its degradation process. This entire system, including ubiquitination and proteasomal degradation, is called the ubiquitin-proteasome system.
Proteasomes are cylindrical, multisubunit proteases found in eukaryotes, eubacteria, and archaebacteria. Eukaryotic proteasomes come in two sizes, the 20S proteasome and the considerably larger adenosine triphosphate-dependent 26S proteasome formed when the 20S proteasome binds a regulatory complex. The 26S proteasome is the central protease in the ubiquitin-mediated proteolytic pathway and is essential for a vast array of cellular processes, including cell-cycle traverse, transcription control, regulation of enzyme levels, and antigen presentation. Both 20S and 26S proteasomes can associate with protein complexes that activate peptide hydrolysis and may serve to localize the enzymes within cells.
Functions of Proteasome
The proteasomal degradation pathway is essential for many cellular processes, including the cell cycle, regulation of gene expression, oxidative stress response, etc. Proteasome degradation products include signaling molecules, tumor suppressors, cell cycle regulators, transcription factors, inhibitory molecules, and anti-apoptotic proteins. Due to their rapid proliferation and defective cell cycle control points, tumor cells are more susceptible to pro-apoptotic stimuli than normal cells. If the degradation process of these proteins is interrupted, it will have a huge impact on tumor cells.
The proteasomes form a pivotal component for the ubiquitin-proteasome system (UPS) and corresponding cellular Protein Quality Control (PQC). Protein ubiquitination and subsequent proteolysis and degradation by the proteasome are important mechanisms in the regulation of the cell cycle, cell growth and differentiation, gene transcription, signal transduction, and apoptosis. Proteasome defects lead to reduced proteolytic activity and the accumulation of damaged or misfolded proteins, which may contribute to neurodegenerative disease, cardiovascular diseases, inflammatory responses autoimmune diseases, and systemic DNA damage responses leading to malignancies.
Physiological Role of The Ubiquitin-Proteasome Pathway
- Regulates the cell cycle.
- Modulates cellular responses to proapoptotic stimuli.
- It plays important roles in the body:
- It can process inactive protein precursors into active proteins.
- It can degrade accumulated proteins to maintain protein balance in the body, especially the activation and degradation of various regulatory proteins in cell signal transduction pathways, controlling cell differentiation, growth, apoptosis, and other processes.
- It can selectively remove mutated, damaged, or misfolded proteins.
Available Resources of Proteasome
Creative BioMart, as a leading biotechnology company, is committed to product development and innovation in the field of biological research. We offer a range of proteasome-related products and resources, click to view all related molecules/targets and research reagents.
The proteasome is an important intracellular degradation system that plays a key role in cell cycle regulation, immune regulation, and protein quality control. The proteasome-related products and services provided by Creative BioMart will assist researchers in these fields. Whether studying the proteasome itself or its application in drug development, Creative BioMart is your partner of choice. Please note that the product types and resources of each proteasome are different, please contact us with any questions or requests.
Fig. 1 The ubiquitin-proteasome pathway. (Ciechanover, A, et al., 1998)
References:
- Ciechanover, A, and A L Schwartz. "The ubiquitin-proteasome pathway: the complexity and myriad functions of proteins death." Proceedings of the National Academy of Sciences of the United States of America vol. 95,6 (1998): 2727-30.
- Tanaka K. The proteasome: overview of structure and functions. Proc Jpn Acad Ser B Phys Biol Sci. 2009;85(1):12-36. doi: 10.2183/pjab.85.12.
