Ubiquitin-like proteins (UBLs) are a class of small proteins that share structural similarities with ubiquitin, a highly conserved and widely distributed protein involved in various cellular processes. These UBLs play critical roles in post-translational modification pathways, regulating protein degradation, localization, and interactions within the cell.
UBLs are characterized by a ubiquitin fold, which consists of a highly conserved β-grasp fold formed by a series of antiparallel β-strands, connected by loops and termini. This fold allows UBLs to interact with various target proteins and participate in diverse protein-protein interactions.
Ubiquitin-like proteins can be conjugated to target proteins through a process called ubiquitination, similar to the conjugation of ubiquitin. This modification has been found to regulate protein stability, trafficking, DNA repair, and a range of other cellular processes. Furthermore, UBLs can also act as molecular markers, contributing to the recognition and degradation of proteins by the proteasome.
UBLs are involved in various cellular pathways, including autophagy, DNA repair, protein quality control, and intracellular trafficking. They have been found to interact with multiple enzymes and adaptor proteins, forming complexes that facilitate their roles in these processes.
Overall, ubiquitin-like proteins are essential players in cellular homeostasis and protein regulation. Their structural and functional similarities to ubiquitin enable them to participate in a wide range of biological pathways, making them crucial components of cellular processes and signaling networks.
