Rho GTPase-based signaling networks control cellular dynamics by coordinating protrusions and retractions in space and time. Here, we reveal a signaling network that generatespulses and propagating waves of cell contractions. These dynamic patterns emerge via self organization from an activator-inhibitor network, in which the small GTPase Rho amplifies itsactivity by recruiting its activator, GEF-H1. Rho also inhibits itself by local recruitment of actomyosin and the associated RhoGAP Myo9b. This network structure enables spontaneous, selflimiting patterns of subcellular contractility that can explore mechanical cues in the extracellularenvironment. Indeed, acto-myosin pulse frequency in cells is altered by matrix elasticity, showingthat coupling of contractility pulses to environmental deformations modulates network dynamics.Thus, our study reveals a mechanism that integrates intracellular biochemical and extracellularmechanical signals into subcellular activity patterns to control cellular contractility dynamics.
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