Cytoskeletal disassembly by optogenetic control of RhoA signaling termination

Abstract

Cellular morphodynamics require adaptive cytoskeletal remodeling, mediated by precisely coordinated activation and termination of RhoA GTPase signaling. RhoA activation is well-studied, but the kinetics and molecular basis of signaling termination remain poorly understood. We engineered an optogenetic toolbox on the single-component BcLOV4 platform for bidirectional control of RhoA activation (opto-GEF11) and termination (opto-DLC1). Prior studies have inferred GTPase inactivation kinetics indirectly, by tracking passive recovery from an activated state, but whether this reflects the kinetics of forward signaling termination remains unclear. Using opto-DLC1, we show that direct RhoA termination is an order of magnitude faster than passive disactivation, despite comparable signaling amplitude. Mechanistically, opto-DLC1 triggered rapid actin disassembly through cofilin disinhibition but drove YAP nuclear efflux at half the rate of opto-GEF11-induced nuclear influx. Together, these findings introduce a platform technology for controlling protein signaling termination, resolve RhoA activation and termination kinetics with sub-second precision, and reveal a mechanistic asymmetry between signaling activation and termination that enables cytoskeletal homeostasis.