The 2001 Nobel Prize in Physiology or Medicine (8 October 2001)
The Nobel Assembly at Karolinska Institutet has today decided to
award The Nobel Prize in Physiology or Medicine for 2001 jointly to
Leland H. Hartwell, R. Timothy (Tim) Hunt and Paul M. Nurse
for their discoveries of "key regulators of the cell cycle"
Summary
All organisms consist of cells that multiply through cell division.
An adult human being has approximately 100 000 billion cells, all
originating from a single cell, the fertilized egg cell. In adults
there is also an enormous number of continuously dividing cells
replacing those dying. Before a cell can divide it has to grow in size,
duplicate its chromosomes and separate the chromosomes for exact
distribution between the two daughter cells. These different processes
are coordinated in the cell cycle.
This year's Nobel Laureates in Physiology or Medicine have made
seminal discoveries concerning the control of the cell cycle.
They have identified key molecules that regulate the cell cycle
in all eukaryotic organisms, including yeasts, plants, animals
and human. These fundamental discoveries have a great impact on
all aspects of cell growth. Defects in cell cycle control may
lead to the type of chromosome alterations seen in cancer cells.
This may in the long term open new possibilities for cancer treatment.
Leland Hartwell (born 1939), Fred Hutchinson Cancer Research Center,
Seattle, USA, is awarded for his discoveries of a specific class
of genes that control the cell cycle. One of these genes called
"start" was found to have a central role in controlling the first
step of each cell cycle. Hartwell also introduced the concept
"checkpoint", a valuable aid to understanding the cell cycle.
Paul Nurse (born 1949), Imperial Cancer Research Fund, London,
identified, cloned and characterized with genetic and molecular
methods, one of the key regulators of the cell cycle, CDK (cyclin
dependent kinase). He showed that the function of CDK was highly
conserved during evolution. CDK drives the cell through the cell
cycle by chemical modification (phosphorylation) of other proteins.
Timothy Hunt (born 1943), Imperial Cancer Research Fund, London,
is awarded for his discovery of cyclins, proteins that regulate
the CDK function. He showed that cyclins are degraded periodically
at each cell division, a mechanism proved to be of general importance
for cell cycle control.