Ubiquitylation, also referred to as ubiquitination, is the process of attaching ubiquitin, a small protein found in almost all tissues of eukaryotic organisms, to another targeted protein. Ubiquitylation can change the activity of a protein or change that protein’s role within the cell, although the most common association scientists make with this process is that it marks targeted proteins for degradation. The theory is that ubiquitylation helps cells to track the use of a molecule so that the molecule is more likely to be disposed of when it has been around for a long time.Ubiquitin attaches to lysine groups of target proteins through the activity of a ubiquitin ligase (E3) and a ubiquitin-conjugating enzyme (E2). These proteins facilitate the activation and transfer of ubiquitin either directly to the target protein or to other ubiquitin proteins that already have been attached to the target protein. Some proteins are ubiquitylated only once, creating an additional functional group at the lysine site. Such a single instance of ubiquitylation on a protein doesn’t necessarily mark it for degradation through the proteasome pathway. Rather, the target protein’s function can be altered by a single ubiquitin because of a change in functional group or protein binding site.
When a chain of more than one ubiquitin molecule attaches to the same target protein, that protein is said to be poly-ubiquitylated. Poly-ubiquitin chains appear to serve multiple purposes, of which the best understood is marking target proteins for degradation through the proteasome. There are seven ways in which one ubiquitin protein can bind to another, meaning that the poly-ubiquitin chains can take on a wide diversity of shapes, each of which may signal a different outcome.
Ubiquitin is found in almost all tissues of eukaryotic organisms and can be found tagged to almost any protein. It is evolutionarily advantageous for all cells of eukaryotic organisms to use the process of ubiquitylation because it removes breaking, worn or sub-functional proteins from cells before the proteins cease functioning entirely. A system that pre-emptively removes proteins from use and tags them for protein recycling keeps cells healthy.
The process of ubiquitylation is still not fully understood, and is therefore understandably an area of intense academic and commercial interest. We are extremely excited about the Affimer binders we have recently developed, and will continue to do so, in this important area of research. To illustrate what we hope to be able to offer life scientists, in 10 years since the Nobel prize for chemistry was awarded to Aaron Ciechanover, Avram Hershko and Irwin Rose “for the discovery of ubiquitin-mediated protein degradation”, just two antibodies have been successfully developed in this field. But our scientists have produced four Affimer binders in a matter of months, and more are in the pipeline!
Of particular interest to researchers could be:
- K6: Anti-diUbiquitin K6-linkage Affimer (44-29)
- K33: Anti-diUbiquitin K33-linkage Affimer (48-1)
- K48: Anti-diUbiquitin K48-linkage Affimer (36-16)
- K63: Anti-Ubiquitin Affimer (UX-K63-20)
View these products, and more, in our catalogue
Further information on ubiqutylation