Ubiquitin is a tiny protein found in nearly all cellular tissues in humans and other eukaryotic bodies. Ubiquitin helps to control the protein processes in the body. This protein can attach to a substrate protein during the process of ubiquitination to alter the way it functions. This can later result in various other products. Ubiquitin is mainly known for its role in apoptosis, hence the molecular title the ‘Kiss of death' for proteins.
Ubiquitin has a molecular mass of 8564.8448 Da and 76 total numbers of residues. This protein participates in numerous functions via conjugation to an extensive range of mark proteins. In addition to that, ubiquitin has key characteristics, including seven lysine residues and a c-terminal tail. It is also highly conserved via eukaryote progression, and there is a 96 percent similarity between yeast and human ubiquitin.
Ubiquitin plays a primary role in many cellular processes, including apoptosis, antigen processing, the transcription and repair of DNA, immune response and inflammation, viral infection, development and differentiation, and ribosome biogenesis, among many others. There are three types of ubiquitination, also known as Ubiquitylation, namely, monoubiquitination and polyubiquitin chains.
Ubiquitination impacts cellular processes by controlling the degeneration of proteins through lysosome and proteasome, regulating the cellular localization of proteins accentuating protein-protein interaction, and stimulating and inactivating proteins.
A whole family of proteins interacts with proteins in the same way, and they are referred to as ubiquitin-like modifiers. The elements in this category can vary significantly in the sequence; however, they have the same structure.
Ubiquitin-like modifiers can sometimes lead to similar results to ubiquitin; however, in some cases, they can differ. For instance, SUMO can bind to a protein marked by ubiquitin for degradation, stabilization and deter it from being transferred to the proteasome.