The Nobel prize in chemistry was awarded to two Israelis, Avram Hershko and Aaron Ciechanover of the Technion in Haifa, and an American, Irwin Rose of the University of California at Irvine, for a discovery that advances the fight against cancer. The three share the $1.3 million prize.
In the late 1970s and early 1980s, the scientists found and named the protein ubiquitin, which marks other proteins for destruction once they have carried out their task, a process that regulates the body. Alternatively, unwanted proteins that linger in the body can cause disease like cancer. The trio’s discovery led to the creation of the cancer drug Velcade, approved last year in the United States, that targets sick cells. Previously, cancer treatments had a tendency to kill cells indiscriminately, a debilitating and potentially lethal complication for the patient.
According to The Royal Swedish Academy of Sciences press release: Aaron Ciechanover, Avram Hershko and Irwin Rose have brought us to realize that the cell functions as a highly-efficient checking station where proteins are built up and broken down at a furious rate. The degradation is not indiscriminate but takes place through a process that is controlled in detail so that the proteins to be broken down at any given moment are given a molecular label, a ‘kiss of death', to be dramatic. The labelled proteins are then fed into the cells' "waste disposers", the so called proteasomes, where they are chopped into small pieces and destroyed.
The label consists of a molecule called ubiquitin. This fastens to the protein to be destroyed, accompanies it to the proteasome where it is recognised as the key in a lock, and signals that a protein is on the way for disassembly. Shortly before the protein is squeezed into the proteasome, its ubiquitin label is disconnected for re-use.
Thanks to the work of the three Laureates it is now possible to understand at molecular level how the cell controls a number of central processes by breaking down certain proteins and not others. Examples of processes governed by ubiquitin-mediated protein degradation are cell division, DNA repair, quality control of newly-produced proteins, and important parts of the immune defence. When the degradation does not work correctly, we fall ill. Cervical cancer and cystic fibrosis are two examples. Knowledge of ubiquitin-mediated protein degradation offers an opportunity to develop drugs against these diseases and others.