A Golden Age for Adhesion

Abstract
It is 70 years since the embryologist Warren Lewis noted the fundamental importance of adhesion to development and physiological function (Lewis, 1922). He wrote: “Were the various types of cells to lose their stickiness for one another and for the supporting extracellular white fibers, reticuli, etc., our bodies would at once disintegrate and flow off into the ground in a mixed stream of ectodermal, muscle, mesenchyme, endothelial, liver, pancreatic, and many other types of cells.” Underlying this striking piece of imagery are a number of remarkable phenomena: (1) in order to differentiate in the first place, cell precursors to those tissues had to adhere to each other, (2) cell adhesion and cell movement had to be coordinated in time and space, and (3) the physiology of both the cells and the tissues to which they contribute depends critically on the appropriate ordering of adhesion events.