Plasma membrane nanodeformations promote actin polymerisation through CIP4/CDC42 recruitment and regulate type II IFN signaling

Abstract

AbstractIn their environment, cells have to cope with mechanical stresses constantly. Among those, nanoscale deformations of plasma membrane induced by substrate nanotopography are now largely accepted as a biophysical stimulus influencing cell behaviour and function. However, the mechanotransduction cascades involved and their precise molecular effects on cellular physiology are still poorly understood. Here, using homemade fluorescent nanostructured cell culture surfaces, we explored the role of Bin/Amphiphysin/Rvs (BAR) domain proteins as mechanosensors of plasma membrane geometry. Our data reveal that distinct subsets of BAR proteins bind to plasma membrane deformations in a membrane curvature radius-dependent manner. Furthermore, we show that membrane curvature promotes the formation of dynamic actin structures mediated by the Rho GTPase CDC42, the F-BAR protein CIP4 and the presence of PI(4,5)P2, independently of clathrin. In addition, these actin-enriched nanodomains can serve as platforms to regulate receptor signaling as they appear to contain Interferon γ receptor (IFNγ-R) and to lead to the partial inhibition of IFNγ-induced Janus-activated tyrosine kinase/signal transducer and activator of transcription (JAK/STAT) signaling.