Light-Inducible Generation of Membrane Curvature in Live Cells with Engineered Bar Domain Proteins

Abstract

Nanoscale membrane curvature is now understood to play an active role in many subcellular processes. Studies of nanoscale membrane curvature effects on protein function thus far have primarily consisted of in vitro studies, as few methods are able to induce membrane curvature in live cells. A new method of generating nanoscale membrane curvature that is dynamic, reversible, and capable of stimulating a large population of cells is desired. Here, we report the development of two optogenetic systems: opto-FBAR and opto-IBAR. Derived from the human FBP17 and IRSp53 proteins, respectively, these systems allow us to induce the formation of positive and negative membrane curvature with fine spatiotemporal precision. In opto-FBAR, blue light activation results in the formation of membrane tubules, controllable down to the subcellular level. Using a modified image analysis program, we are able to quantify levels of plasma membrane tubulation in cells. opto-IBAR activation results in the formation or elongation of cellular membrane protrusions and filopodia. These systems present a novel approach for controlling nanoscale membrane curvature in live cells.