ABSTRACT
The aim of this chapter is to describe methods of creating membrane nanotubes by pulling them from the surface of giant unilamellar vesicles (GUVs) using external forces of different origins. Since the GUV diameter is several orders of magnitude larger than that of the pulled tube, it acts as a quasi-flat and quasi-infinite lipid reservoir for the nanotube. So far, this method has seen two main applications: (1) measuring the equilibrium and dynamical mechanical properties of membranes and, more recently, (2) characterizing cellular processes occurring at curved membrane interfaces. The chapter first summarizes the theoretical basis that underlies membrane tube-pulling experiments. Then, it describes the most widely used tube-pulling setup employing micropipette aspiration techniques, optical tweezers and confocal microscopy, highlighting experimental details and difficulties surrounding the experiment. Alternative methods of pulling membrane nanotubes and their applications are also introduced and past and future applications of the tube-pulling assay are outlined.
