LEMONADE: Lego-like membrane tension analyzer based on self-assembled DNA elastic networks.

Abstract

Membrane tension regulates and is affected by many cellular processes, including cell motility and membrane trafficking. However, the role of membrane tension in such processes is poorly understood because of difficulties in measuring dynamic membrane tension changes in live cells. Current approaches for membrane tension measurements can be broadly divided into two categories. In the first, fluorescence-based signals from small molecular probes that insert into cellular membranes are used. These allow convenient mapping of the signals throughout the cell membrane, but probe local membrane properties which are not always easy to relate to membrane tension. In addition, they are prone to artefacts due to membrane heterogenicities. The second type of approach relies on pulling a thin membrane tether from the cell surface. The restoring force acting on the tether is related to membrane tension and can be measured using optical tweezers. However, this approach requires specialized equipment and tension is measured at a single location. To overcome these challenges, we are developing a novel approach based on the self-assembly of an elastic network on the cell surface we call LEMONADE (Lego-like membrane tensionanalyzer based on self-assembled DNA elastic networks). The new membrane tension sensor relies on membrane-anchored Lego-like DNA nanostructures that are linked by elastic connectors with a FRET pair modification. Cell membrane area changes will result in transient FRET signals which can be detected throughout the cell surface using standard live fluorescence microscopy. We will report our progress in the design, assembly, and calibration of LEMONADE.