Science
By Russell Hodge
The inner workings of a protein shredder
Proteins are born as string-like molecules that must be folded into precise shapes to perform their jobs in cells. Their final shape and chemistry allow them to dock onto other molecules, snap into place in "molecular machines," and carry out a wide range of functions. But the process of folding isn't perfect, and misfolded molecules trigger Alzheimer's, Huntington's, and many other diseases. Often, however, cells detect and destroy defective proteins. Understanding how they do so is crucial to discovering why some misfolded molecules slip by to cause disease. Thomas Sommer's group at the MDC has now gained important insights into the assembly of part of the quality control system. The study, published in the December 11, 2009 issue of Molecular Cell, reveals how the structure of a molecular machine manages to cope with a wide variety of defects.