The proteasome is a complex molecular machine that degrades proteins modified by ubiquitin. It recognizes and processes ubiquitin-protein conjugates through a series of steps involving ATP-dependent unfolding, translocation, and deubiquitination. The proteasome contains a 28-subunit core particle (CP) and a regulatory particle (RP) of 19–20 subunits. The CP is a barrel-like structure with four stacked seven-membered rings, and its proteolytic active sites are sequestered within its interior. The RP, which includes six ATPase subunits, mediates the recognition and processing of substrates, and contains ubiquitin receptors such as Rpn10, Rpn13, Rad23, Dsk2, and Ddi1. These receptors recognize ubiquitin tags and facilitate substrate entry into the CP. The proteasome also contains deubiquitinating enzymes that act on substrates prior to degradation, helping to suppress substrate degradation. The proteasome degrades substrates processively, which reflects its compartmentalized structure and substrate translocation mechanism. The proteasome is important for various biological processes, including cell cycle control, apoptosis, and immune response. It is also involved in the degradation of misfolded and aberrant proteins, and its dysfunction is associated with various diseases. The proteasome is a highly complex enzyme, and its function is regulated by various mechanisms, including the interaction of its subunits with other proteins and the availability of ATP. The proteasome is also involved in the degradation of ubiquitin itself, and its activity is regulated by various factors, including ubiquitin levels and the presence of specific enzymes. The proteasome is a key player in the ubiquitin-proteasome system, which is the major cytosolic proteolytic system in eukaryotes. The proteasome's function is essential for maintaining cellular homeostasis and is involved in various cellular processes, including protein quality control and signal transduction. The proteasome is a highly complex and dynamic machine, and its function is regulated by various mechanisms, including the interaction of its subunits with other proteins and the availability of ATP. The proteasome is also involved in the degradation of ubiquitin itself, and its activity is regulated by various factors, including ubiquitin levels and the presence of specific enzymes. The proteasome is a key player in the ubiquitin-proteasome system, which is the major cytosolic proteolytic system in eukaryotes. The proteasome's function is essential for maintaining cellular homeostasis and is involved in various cellular processes, including protein quality control and signal transduction.The proteasome is a complex molecular machine that degrades proteins modified by ubiquitin. It recognizes and processes ubiquitin-protein conjugates through a series of steps involving ATP-dependent unfolding, translocation, and deubiquitination. The proteasome contains a 28-subunit core particle (CP) and a regulatory particle (RP) of 19–20 subunits. The CP is a barrel-like structure with four stacked seven-membered rings, and its proteolytic active sites are sequestered within its interior. The RP, which includes six ATPase subunits, mediates the recognition and processing of substrates, and contains ubiquitin receptors such as Rpn10, Rpn13, Rad23, Dsk2, and Ddi1. These receptors recognize ubiquitin tags and facilitate substrate entry into the CP. The proteasome also contains deubiquitinating enzymes that act on substrates prior to degradation, helping to suppress substrate degradation. The proteasome degrades substrates processively, which reflects its compartmentalized structure and substrate translocation mechanism. The proteasome is important for various biological processes, including cell cycle control, apoptosis, and immune response. It is also involved in the degradation of misfolded and aberrant proteins, and its dysfunction is associated with various diseases. The proteasome is a highly complex enzyme, and its function is regulated by various mechanisms, including the interaction of its subunits with other proteins and the availability of ATP. The proteasome is also involved in the degradation of ubiquitin itself, and its activity is regulated by various factors, including ubiquitin levels and the presence of specific enzymes. The proteasome is a key player in the ubiquitin-proteasome system, which is the major cytosolic proteolytic system in eukaryotes. The proteasome's function is essential for maintaining cellular homeostasis and is involved in various cellular processes, including protein quality control and signal transduction. The proteasome is a highly complex and dynamic machine, and its function is regulated by various mechanisms, including the interaction of its subunits with other proteins and the availability of ATP. The proteasome is also involved in the degradation of ubiquitin itself, and its activity is regulated by various factors, including ubiquitin levels and the presence of specific enzymes. The proteasome is a key player in the ubiquitin-proteasome system, which is the major cytosolic proteolytic system in eukaryotes. The proteasome's function is essential for maintaining cellular homeostasis and is involved in various cellular processes, including protein quality control and signal transduction.