ubiquitinproteasomvägen

ubiquitinproteasome system is a vital cellular process responsible for protein degradation. It involves the covalent attachment of a small protein called ubiquitin to target proteins. This ubiquitination acts as a signal, marking the protein for destruction by the proteasome, a large multi-subunit protease complex. The system plays a crucial role in maintaining cellular homeostasis by removing damaged, misfolded, or no longer needed proteins. This degradation is essential for various cellular functions including cell cycle regulation, DNA repair, immune response, and the elimination of abnormal proteins that could lead to disease. The process begins with ubiquitin ligases, enzymes that attach ubiquitin to substrate proteins. Deubiquitinating enzymes can also remove ubiquitin, reversing the signal. Once polyubiquitinated, a protein is recognized by the proteasome and unfolded, then threaded through its catalytic core where it is broken down into small peptides. Dysregulation of the ubiquitin-proteasome system has been implicated in numerous diseases, including cancer, neurodegenerative disorders like Alzheimer's and Parkinson's, and immune deficiencies.