Nobel prize for medicine: how oxygen affects cells

THOSE WHO pick the winners of Nobel science prizes do sometimes plump for big and obvious names. Often, though, they seem to take great joy in shining the spotlight of fame onto researchers little known outside their own fields, let alone to the general public. This year’s prize in physiology or medicine is a classic of the genre. The laureates, William Kaelin, Sir Peter Ratcliffe and Gregg Semenza, have each contributed to a discovery that, though crucial to understanding how human bodies work, is almost invisible to the wider world. This discovery is how cells detect and adjust to the level of oxygen available to fuel their activities.Such biochemical arrangements almost always rely on feedback loops—and the crucial molecule in the loop that matches cell physiology to oxygen availability is a protein complex called hypoxia-inducible factor (HIF). HIF was discovered and named by Dr Semenza, who works at Johns Hopkins University, in Baltimore. In the 1990s Dr Semenza was studying erythropoiesis, the process that generates red blood corpuscles. These are the cells that carry oxygen in the bloodstream, and their number depends on how much oxygen there is around. Professional athletes, for example, often train at high altitude, where the thin air means oxygen is scarce, in order to grow extra red blood cells that will assist their respiration when they compete nearer to sea level.