1 Cellular Biophysics, Institute of Biology, Humboldt University Berlin, 10117 Berlin, Germany; Leibniz Forschungsinstitut für Molekulare Pharmakologie, 13125 Berlin, Germany. Electronic address: andrew.plested@hu-berlin.de.
2 Department of Biochemistry and Molecular Biology, Center for Membrane Biology, University of Texas Health Science Center at Houston, Houston, Texas. Electronic address: vasanthi.jayaraman@uth.tmc.edu.