Benny Geiger: A force in the study of focal adhesions

F ocal adhesions are protein clusters that form where integrins attach to the extracellular matrix. But, says Benjamin Geiger, from the Weizmann Institute in Israel, focal adhesions are not simply a cellular footprint; they are also sensory devices that transmit information about the properties of the extracellular milieu to the cell interior. Geiger should know; he's spent most of his career energetically studying how adhesion sites sense and communicate these signals to the cell. A night owl, Geiger says he gets some of his most useful work done in the peace of the night. His tireless efforts have generated many novel insights about what proteins are found in focal adhesions (1, 2) and what they do there (3, 4). Along the way, he's also helped to develop new technologies to probe cell adhesion sites (4, 5). We reached him late one evening at his lab to talk about some of the things that keep him up and energized all night. Early in your career, you identifi ed the cytoskeletal adaptor protein vinculin… When I went to La Jolla from Israel in 1977 to start my postdoc with Jon Singer at UC San Diego, the fi eld of cyto-skeletal research was just starting to explode, almost out of nowhere. Major questions emerging at that time were: how is this intracellu-lar machinery affected by the outside world, and how is it participating in sensing the environment in which cells are located? We and others started to look into the mechanism by which cytoskeletal filaments link to the membrane, for which we needed high-resolution technologies for localizing molecules, such as immuno-electron microscopy. I was looking for the glue that connects actin to the membrane in specific regions of the cell. One candidate for this job was the protein ␣-actinin, but, when we tried to localize it, we saw that it wasn't really located close enough to the membrane to be the direct link. While I was purifying ␣-actinin, I got as a by-product an unknown protein with a molecular weight of approximately 130 kilodaltons. To fi gure out what this protein might do, I prepared antibodies to it and used immunofluorescence micros-copy to fi nd where it was located within cells. And when I did this—I really remember this moment of discovery—I saw a most beautiful array of arrowhead-shaped structures all around the cells that were all localized at the ends of actin …