Sue Biggins studies the machinery that dividing cells use to ensure their daughter cells receive the correct allotment of chromosomes. Getting it right is crucial: cells with too many or too few chromosomes can cause cancer, birth defects, or miscarriage.
Much of Biggins's work focuses on kinetochores, structures that connect chromosomes to the long, thin microtubules that tug them to the appropriate ends of a dividing cell. She has shed light on how cells make sure that these structures – which comprise hundreds of proteins and must be reassembled every time a cell divides – are positioned in the right spot on chromosomes. She also showed how a protein called Aurora B forces cells to stop and fix things if microtubules are incorrectly attached to a kinetochore, before cell division can proceed.
In 2010, Biggins purified kinetochores from yeast cells and reconstituted their attachments to microtubules for the first time. Suddenly, a variety of questions became accessible. Her first success with the system was the surprising finding that tension helps stabilize microtubules' attachment to kinetochore. Electron microscopy images of the purified kinetochores revealed the structures' shape for the first time.
Biggins is now focusing on understanding the assembly, regulation and functions of this complex macromolecular machine using yeast and human cells.