Isolating SRP

Like a crate of beer ready to be shipped overseas, secretory proteins carry a label that says, “For Export.” With clever experiments, Günter Blobel of Rockefeller University and his post-doc Bernhard Dobberstein (Blobel and Dobberstein, 1975a,b) showed that the cell's export label is the signal sequence, a short stretch of amino acids that guides the forming protein to the ER (see “Lost in translation: the signal hypothesis” JCB 170:338). But the group still didn't know how the emerging protein recognized the ER or traversed the membrane, or what enzyme clipped off the signal sequence. When Dobberstein started his own lab at the European Molecular Biology Laboratory in Heidelberg, Germany, two teams began vying to solve these questions, lobbing papers across the Atlantic. “It was highly competitive, but it was friendly,” Dobberstein recalls. Peter Walter, who was then Blobel's new graduate student and is now a...