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Aaron Ciechanover

Nobel Prize in Chemistry

2004

Professor Aaron Ciechanover studies the turnover of proteins.  He received his medical degree (MD) from the Hebrew University of Jerusalem, and then a doctorate in biology (DSc) from the Technion in Haifa, where along with his mentor, Professor Avram Hershko, he discovered the ubiquitin system for cellular protein degradation.     


Proteins constitute both the structural (bone, skin) and functional (enzymes, sensory organs) elements of all organisms.  They are sensitive to damage by irradiation, mutations, temperature and therefore must be replaced.  They also have to be removed once they completed their function and are not needed anymore.  However, their mechanism of removal and recycling had not been known, Prof. Aaron Ciechanover (along with Prof. Avram Hershko and Irwin Rose) discovered that a small protein called ubiquitin marks the old proteins for destruction. 


For his discovery, Prof Ciechanover and his colleagues were awarded the Nobel Prize in Chemistry in 2004. 


“The (protein recycling) mechanism is novel as it is specific.  It removes only damaged and the ‘not needed anymore’ proteins, sparing all the remaining ones” said the Israeli biologist.  


The modification of proteins with ubiquitin has been recognised as an essential process in the life of the cell. Scientists have found that diseases from numerous malignancies (such as tumors of the kidney and different leukemias), and neurodegenerative diseases (Alzheimer's and Parkinson's) are all associated with defects in the ubiquitin system. 


Prof Ciechanover continues to study the link between ubiquitin and diseases like cancer and neurodegenerative diseases. For cancer, he is trying to manipulate the ubiquitin system to work in a certain path so as to suppress tumours. The ubiquitin system, he explains, is responsible for the satiety sensing of the cell, whether it is hungry or has sufficient nutrients. If this hungry button can be switched off, then the cancer cells are starved to death without “knowing” it.  They simply do not sense hunger. Through this method, he hopes to develop modulators that can be converted to drugs. 


But he hastened to add that finding a cure for cancer and other diseases is a difficult challenge. Scientists and physicians can diagnose a disease earlier, push the disease back, make it chronic, and at best postpone its eruption. A cure is not simple as it involves reversing a process that frequently is beyond our understanding. Drug discovery is arduous and cumbersome as it must involves also clinical trials and human beings are much more complex that inbred laboratory mice.  For cancer it is clear that it will always require management by several drugs, attacking it from different directions.   


Prof Ciechanover is Israel’s first Nobel Laureate in Science along with Prof. Avram Hershko He wants young scientists to realise that they can also have an impact in science. It does not matter where they are based or how small or young is their country is. It is the passion and desire to pursue their scientific interest that will shape their research path. 


In 2000, he received the Albert Lasker Award for Basic Medical Research and in 2003, he was awarded the Israel Prize for Biology. He is currently a Technion Distinguished Research Professor in the Faculty of Medicine at the Technion-Israel Institute of Technology, a world leading science and technology university.