title: Morphological characterization of molecular complexes present in the synaptic cleft.
abstract: We obtained tomograms of isolated mammalian excitatory synapses by cryo-electron tomography. This method allows the investigation of biological material in the frozen-hydrated state, without staining, and can therefore provide reliable structural information at the molecular level. We developed an automated procedure for the segmentation of molecular complexes present in the synaptic cleft based on thresholding and connectivity, and calculated several morphological characteristics of these complexes. Extensive lateral connections along the synaptic cleft are shown to form a highly connected structure with a complex topology. Our results are essentially parameter-free, i.e., they do not depend on the choice of certain parameter values (such as threshold). In addition, the results are not sensitive to noise; the same conclusions can be drawn from the analysis of both nondenoised and denoised tomograms.
authors.affiliation: Max Planck Institute for Biochemistry, Martinsreid, Germany.
authors.forename: Vladan
authors.initials: V
authors.lastname: Lucić
authors.forename: Ting
authors.initials: T
authors.lastname: Yang
authors.forename: Gabriele
authors.initials: G
authors.lastname: Schweikert
authors.forename: Friedrich
authors.initials: F
authors.lastname: Förster
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Baumeister
mesh_terms: D000818:Animals; D020285:Cryoelectron Microscopy; D008322:Mammals; D046912:Multiprotein Complexes / Q000032:analysis / Q000648:ultrastructure; D011487:Protein Conformation; D013569:Synapses / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D046912:Multiprotein Complexes