Cell biology: Stretching the imagination.


T he lecturer flattened a tangle of sticks and elastic on to the desk. He let go, and the structure pinged back into shape. It was a demonstration of ‘tensegrity’, a term constructed by the engineer Buckminster Fuller for situations in which push and pull have a ‘win–win relationship’ with each other. Fuller mashed the word together — from the components tensional integrity — to describe the way sculptor Kenneth Snelson used taut wires and stiff poles to make strong yet flexible monuments. Among the students, Donald Ingber could see the ingenious engineering in the sculptures — but he also saw biology. Ingber was an undergraduate in molecular biophysics at Yale University; the course in three-dimensional design had seemed apt. But what he saw there changed the course of his professional life. At that time, in the late 1970s, researchers were publishing the first scientific papers describing how cells are propped up by an internal scaffolding, or cytoskeleton. “I immediately thought: ‘Oh, so cells must be tensegrity structures’,” Ingber says. On returning to the lab, he eagerly explained this idea to one of the postdocs, who was less than impressed. “He told me: ‘Just never mention that again’,” Ingber recalls. Then, as now, most cell biologists had little time for architecture and engineering. When they want to understand why a cell behaves the way that it does, they try to identify the genes, proteins and signalling molecules that are thought to exert control. But to Ingber there was an obvious gap between the dramatic events that mould a developing embryo and the molecular explanations that were given for them in his developmental-biology class. “What I saw before my eyes was something that was incredibly physical, mechanical in nature: twisting, bending, folding,” he says, “and then I got into cell biology, and it was all chemical.” Thirty years on, work from Ingber’s group and many others has started to convince cell biologists to embrace the missing physics. Their findings are remarkable. Pull a stem cell in one way and it starts developing as a brain cell; stretch it in another, and a bone cell is its more likely fate. Change the mechanical stresses on cancer cells and they can start to behave more like healthy ones. Among this work’s implications, few are more important than the consequences for cell therapy and tissue engineering, in which researchers hope to use new cells to repair damaged organs. If these cells encounter the ‘wrong’ kinds of mechanical stresses, they could conceivably end up doing more harm than good. The discoveries are giving biologists a fresh appreciation of the body’s physical nature. Hearts pump, muscles stretch, blood surges, feet pound. And on the microscopic scale, fluids flow and cells jostle with their neighbours. When Ingber, now at Harvard University, talks about his ideas today, he doesn’t get quite the same frosty reception that he once did. “There’s no doubt,” he says, “in the past five years it has exploded.”

DOI: 10.1038/456696a

Cite this paper

@article{Ainsworth2008CellBS, title={Cell biology: Stretching the imagination.}, author={Claire Ainsworth}, journal={Nature}, year={2008}, volume={456 7223}, pages={696-9} }