title: Visualizing active membrane protein complexes by electron cryotomography.
abstract: Unravelling the structural organization of membrane protein machines in their active state and native lipid environment is a major challenge in modern cell biology research. Here we develop the STAMP (Specifically TArgeted Membrane nanoParticle) technique as a strategy to localize protein complexes in situ by electron cryotomography (cryo-ET). STAMP selects active membrane protein complexes and marks them with quantum dots. Taking advantage of new electron detector technology that is currently revolutionizing cryotomography in terms of achievable resolution, this approach enables us to visualize the three-dimensional distribution and organization of protein import sites in mitochondria. We show that import sites cluster together in the vicinity of crista membranes, and we reveal unique details of the mitochondrial protein import machinery in action. STAMP can be used as a tool for site-specific labelling of a multitude of membrane proteins by cryo-ET in the future.
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany.
authors.forename: Vicki A M
authors.initials: VA
authors.lastname: Gold
authors.affiliation: Institute for Biochemistry and Molecular Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Ieva
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Walter
authors.affiliation: Institute for Biochemistry and Molecular Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Pfanner
authors.affiliation: Institute for Biochemistry and Molecular Biology and BIOSS Centre for Biological Signalling Studies, University of Freiburg, 79104 Freiburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: van der Laan
authors.affiliation: Department of Structural Biology, Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany.
authors.forename: Werner
authors.initials: W
authors.lastname: Kühlbrandt
mesh_terms: D020285:Cryoelectron Microscopy / Q000379:methods*; D008565:Membrane Proteins / Q000737:chemistry / Q000648:ultrastructure*; D008928:Mitochondria / Q000737:chemistry / Q000378:metabolism; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism
chemical_list: D008565:Membrane Proteins; D029701:Saccharomyces cerevisiae Proteins