proteasomlarca

Proteasomes are large protein complexes found in the cytoplasm of eukaryotic cells. They play a crucial role in the degradation of proteins that are no longer needed or have become damaged. This process is essential for maintaining cellular homeostasis and preventing the accumulation of dysfunctional proteins. Proteasomes are composed of a barrel-shaped structure made up of four stacked rings of proteins, with a central cavity where the protein degradation occurs. The degradation process involves the unfolding of the target protein, its threading through the central channel, and its subsequent breakdown into smaller peptides. Proteasomes are regulated by various factors, including ubiquitin, a small protein that tags proteins for degradation. There are two main types of proteasomes: the constitutive proteasome, which is always active, and the immunoproteasome, which is induced in response to viral infections and plays a role in antigen presentation. Proteasomes are also found in prokaryotic cells, where they perform similar functions. The study of proteasomes has significant implications for understanding diseases such as cancer, neurodegenerative disorders, and infectious diseases.