The fact that the 2001 Nobel Price in Medicine has been awarded to three Yeast researchers should not lead to the wrong conclusion that the Nobel committee appreciated the fight against alcoholism or overweight. In fact without the tasty products of Brewers or Bakers Yeast (Saccharomyces cerevisiae) our lives would be much more healthy but – honestly – less nicer. Coming to the point, the award really recognizes the contributions of Leland Hartwell, Paul Nurse and Timothy Hunt to the understanding the control mechanisms of the cell cycle, the molecular cell division management system.
I myself did research on cell cycle regulation in Yeast in the late ’90s. As a Yeast guy in an innovative scientific environment that deals with frogs, mice and human cell lines you were always seen as an eccentric – and somehow funny – specialist (and it has always been a challenge to explain that my experiments are not related to the Yeast contaminations in the cell culture lab). Later I was glad to have the opportunity to cooperate and to discuss my results with Gustav Ammerer and Kim Nasmyth in Vienna, two other great Yeast geneticists.
Brewers Yeast – for example – is a budding organism (that is why it is also called Budding Yeast). Daughter cells are formed by small buds growing at the Yeast cell surface. This closely resembles the division of mammalian cells resulting in two daughter cells, e.g.. The key issue for the cell cycle now is to synchronize DNA replication with cell growth and division. And vice versa, the DNA replication needs to be reliably inhibited in the case that there is no division. So, the cell cycle is a series of cell functions controlling the whole life span of one cell generation. It starts over and over again until cell aging or other mechanisms stop the propagation. If the cell cycle does not work correctly cells either stop division or have improperly copied chromosomes or propagate uncontrolled. In humans the latter is connected to cancer.
Here the medical relevance of research with Yeasts like S. cerevisiae and Schizosaccharomyces pombe comes in. Yeasts as model organisms for the understanding of common functions in eucaryotic cells. Yeast cells as easy to cultivate mini labs offering research opportunities as regards fundamental cell activities that are too difficult to study in higher cells with their much more complex regulation networks. Well, if we have learned something about cell cycle regulation in Yeast during the past years then that it is even pretty complex in this very simple organism. Today we know a tight network of internal and external signals including the cell metabolism as well as the cytoskeleton. It looks like that there is not just a simple ‘clock’ but a whole system of communicating proteins with checkpoints and feedback loops. We can use these findings in Yeast to look for homologies and similarities in higher organisms. By comparing functionally known Yeast genes and proteins with the human genome and proteome we will be able to identify new research objectives as well as putative pharmaceutical targets.
To my view this “Nobel Prize for Yeast” is an appreciation of the role of model organisms in modern biomedical science. Understanding them leads to a faster understanding of the molecular basics of cellular malfunctions in humans. As a Yeastman still carrying small buds in my heart I congratulate the Nobel committee on its decision.
Originally published in November 2001 by Inside-Lifescience, ISSN 1610-0255.