The Shaw Prize in Life Science and Medicine 2017 is awarded in equal shares to Ian R Gibbons, Visiting Researcher, Department of Molecular and Cell Biology, University of California, Berkeley, USA, and Ronald D Vale, Professor, Cellular and Molecular Pharmacology Department, University of California, San Francisco and an Investigator of the Howard Hughes Medical Institute, USA, for their discovery of microtubule-associated motor proteins: engines that power cellular and intracellular movements essential to the growth, division, and survival of human cells.
Animal and plant cells possess an elaborate network of cables and filaments that organize the cytoplasmic traffic of material with the precision of a well-engineered motorway. Some compartments of cells move over short distances on the range of microns whereas others, particularly in nerve cells, may traverse from the cell body to the tip of a nerve terminal, from millimeters to as much as many centimeters away. The first such filaments to be discovered are composed of a protein called actin, the same protein that provides the striatal structure of a muscle cell. Actin filaments slide past one another as the basis of muscle contraction powered by a motor protein called myosin. The action of the myosin motor to slide actin filaments was first described in muscle tissues back in the 1940s and was rediscovered in the 1970s as a basis for contractile events in all other cells that possess a nucleus, the eukaryotes. Eukaryotic cells also have another network based on a protein called tubulin, which assembles into a cylindrical cable called the microtubule. Microtubules represent the conveyor belt along which membrane compartments are moved over long distances in the cell and serve as the basis of the beating motion of cilia which line the surface of cells to promote fluid movement, for example in the blood vessels and intestines, and also the motion of flagella that propel single-cell eukaryotes in their fluid environments. Microtubules also organize the regular segregation and inheritance of chromosomes that duplicate, divide and then partition into daughter cells during cell division.