David Goldfarb, professor of biology at the University of Rochester, studied the yeast Saccharomyces cerevisiae and found that contrary to what biologists have believed, the cell would "eat" its own nucleus to rid itself of aged or damaged sections. Though it's long been known that cells frequently break down and recycle various cell parts in a process called autophagy (after the Greek for "self-eating"), biologists thought that eating the nucleus was strictly off-limits. The nucleus, after all, is sort of the control center of the cell, and where the cell stores its most precious possessions such as its DNA. Eating it would be a bit like lunching on your own brain.
Goldfarb, however, found that the yeast can eat its nucleus by taking it apart piece by piece, removing non-essential bits and leaving behind the essential components such as the chromosomes.
"In human society, the business of collecting and recycling garbage isn't a very glamorous enterprise, but in the less prestige-oriented world of cells, it's invaluable," says Goldfarb. "We now know just how critical this process is, since a unique and elegant autophagic mechanism evolved to allow the piecemeal degradation of an otherwise essential organelle."
Autophagy is really a family of related processes that identify and deliver useful organic molecules, called macromolecules, to the cell's lysozymes or vacuoles. Lysozymes and vacuoles are much like our own stomachs, filled with acid and hydrolytic enzymes capable of reducing macromolecules to their minimal parts. These parts are then shuttled where they are used either to stoke the metabolic fires or as building ma
Contact: Jonathan Sherwood
University of Rochester