ABOVE: To learn how cancer develops in the mammary glands of mice, Zena Werb has studied hyperplasia in MMTV-neu tumors. ©Vicki Plaks
When no one in Zena Werb’s University of California, San Francisco lab wanted to investigate whether elements of the three-dimensional web of macromolecules surrounding cells could communicate with those cells, she decided to do the experiment herself.
It was the 1980s, a time when scientists saw this web, called the extracellular matrix (ECM), as primarily a support structure for cells. But Werb’s study showed that proteins within the matrix are involved in signaling. Specifically, she discovered that integrins, transmembrane molecules that help adhere a cell to its surroundings, not only bind but respond to ECM proteins, activating intracellular signaling pathways—regulating, for example, the expression of genes that encode ECM-degrading enzymes called matrix metalloproteinases (MMPs). The extracellular matrix was more than just a scaffold, Werb realized—a concept that became ...
