Ubiquitination is seen as the "kiss of death" for a protein. During ubiquitination, a protein is inactivated by attaching ubiquitin to it, which then acts as a tag, signaling that the protein requires degradation. (1) In many genetic diseases, mutated proteins can perform their jobs but are tagged with Ubiquitin for destruction by the cell's quality control mechanisms. (2) Cystic fibrosis is one such disease. Cystic Fibrosis (CF) is an inherited autosomal recessive disease whose lethality arises from a CFTR malfunction, a single chloride (Cl-) ion channel protein. CF patients harbor mutations in the CFTR gene that misfold the resulting CFTR protein, rendering it inactive and mislocalized. (3)
Dr. Kanner and his team at Columbia University were interested in deubiquitinase enzymes (DUBs). These enzymes can remove ubiquitin tags, but simply increasing DUB activity would indiscriminately rescue all proteins in a cell marked for destruction, which would be overall harmful. (4)
They then developed a new technology using nanobodies to prevent specific proteins from being destroyed inside cells. Engineered deubiquitinases or enDUBs for short—combines a synthetic nanobody that recognizes a specific protein with an enzyme that can rescue proteins tagged for destruction. The enDUBs prevented the destruction of the misfolded proteins, and the proteins migrated to their normal locations in the cell membrane, where they performed their normal functions. (4)
According to their paper, Targeted deubiquitination rescues distinct trafficking-deficient ion channelopathies, "CF-targeted enDUBs synergistically rescued common (ΔF508) and pharmacotherapy-resistant (N1303K) CF mutations when combined with the US Food and Drug Administration (FDA)-approved drugs Orkambi (lumacaftor/ivacaftor) and Trikafta (elexacaftor/tezacaftor/ivacaftor and ivacaftor). Altogether, targeted deubiquitination via enDUBs provides a powerful protein stabilization method that not only corrects diverse diseases caused by impaired ion channel trafficking but also introduces a new tool for deconstructing the ubiquitin code in situ." (4)
This groundbreaking approach can be applied to any protein in the cell, not just membrane proteins or proteins altered by genetic mutations in the future, leading to breakthroughs in treatment for any disease where protein degradation is a factor, including cancer and epilepsy.
References:
Shiel Jr., William C. “Medical Definition of Ubiquitination” Medicinenet. https://www.medicinenet.com/ubiquitination/definition.htm
Finley, Daniel, and Vincent Chau. "Ubiquitination." Annual review of cell biology7.1 (1991): 25-69.