Figure 3.

The ECM remodeling process. The three stages of ECM remodeling: (1) ECM deposition and post-translational modification (left), (2) force-mediated ECM modification (middle), and (3) ECM degradation (right) are illustrated with collagen I as an example. In the ECM deposition and post-translational modification step, individual collagen chains are first transcribed/translated. The collagen chains then form a triple helix, after which they are secreted, and the propeptides necessary for triple helix formation are removed. Secreted collagen fibers undergo various modifications such as enzymatic cross-linking. In the force-mediated ECM modification step, cellular forces are transduced via ECM receptors such as integrins to deform and align collagen fibers. Finally, in the ECM degradation step, collagen fibers are degraded extracellularly via various proteolytic enzymes or intracellularly in lysosomes following internalization.