Peter Ratcliffe

Ratcliffe discovered that cells have a direct molecular mechanism for sensing oxygen levels through a protein complex called HIF (hypoxia-inducible factor). He showed that under normal oxygen conditions, HIF is rapidly destroyed by an oxygen-dependent enzymatic process, but when oxygen drops, HIF accumulates and switches on hundreds of genes involved in red blood cell production, blood vessel formation, and energy metabolism.

Ratcliffe shared the 2019 Nobel Prize in Physiology or Medicine with William Kaelin Jr. of Harvard University/Dana-Farber Cancer Institute and Gregg Semenza of Johns Hopkins University. The three were recognized for their collective work revealing how cells sense and adapt to oxygen availability, a process fundamental to development, physiology, and diseases including cancer and anemia.

HIF (hypoxia-inducible factor) is a transcription factor that activates genes allowing cells to survive and adapt when oxygen is scarce. Understanding the HIF pathway has led to new treatments, including drugs like roxadustat that stimulate red blood cell production for chronic kidney disease patients, and strategies to cut off a tumor's blood supply, since many cancers hijack HIF to grow new blood vessels.

Ratcliffe is a professor at the University of Oxford and also serves as director of clinical research at the Francis Crick Institute in London. Much of his pioneering oxygen-sensing research was conducted at the University of Oxford, where he leads the Target Discovery Institute and the Ludwig Institute for Cancer Research laboratory.