CYK-1/Formin activation in cortical RhoA signaling centers promotes organismal left–right symmetry breaking
Teije C. Middelkoop, Júlia Garcia-Baucells, Porfirio Quintero-Cadena, Lokesh G. Pimpale, Shahrzad Yazdi, Paul W. Sternberg, Peter Groß, Stephan W. Grill
Abstract
genetics with quantitative imaging and thin film, chiral active fluid theory to show that, while Non-Muscle Myosin II activity drives cortical actomyosin flows, it is permissive for chiral counterrotation and dispensable for chiral symmetry breaking of cortical flows. Instead, we find that CYK-1/Formin activation in RhoA foci is instructive for chiral counterrotation and promotes in-plane, active torque generation in the actomyosin cortex. Notably, we observe that artificially generated large active RhoA patches undergo rotations with consistent handedness in a CYK-1/Formin-dependent manner. Altogether, we conclude that CYK-1/Formin-dependent active torque generation facilitates chiral symmetry breaking of actomyosin flows and drives organismal left-right symmetry breaking in the nematode worm.