In an intriguing series of experiments carried out many years ago, a common scientific belief, feted by no less than three Nobel prizes, was brought into question. The observations were about proteins-the molecules that the genetic code specifies and that are in one way or another central to all of life's activities. The experiments however were not about what proteins do, but how they are moved, in particular how they are moved from where they are made to where they act. The results of these studies conflicted with the standard view of how this happens, and thus became controversial. The standard view, the vesicle theory of protein secretion, envisions proteins being carried within and out of cells en masse in membrane-bound sacs or vesicles. The controversial experiments demonstrated that to the contrary individual protein molecules cross the relevant membranes as a result of their own motion. This was thought to be impossible at the time. Proteins Crossing Membranesis a personal narrative that tells the story of the controversy. Among other things, the author illustrates that scientists, like the rest of us, can rigidly hold onto their beliefs despite evidence that they are misguided. Key FeaturesReviews the data in support and critical of the vesicle theory of protein secretionExplores the ways scientists respond to evidence that challenges a favored theoryDocuments the author's personal experiences in this conflict-laden situation | Proteins Crossing Membranes by Stephen Rothman, Paperback | Indigo Chapters