TY  - JOUR
A1  - Mrestani, Achmed
A1  - Pauli, Martin
A1  - Kollmannsberger, Philip
A1  - Repp, Felix
A1  - Kittel, Robert J.
A1  - Eilers, Jens
A1  - Doose, Sören
A1  - Sauer, Markus
A1  - Sirén, Anna-Leena
A1  - Heckmann, Manfred
A1  - Paul, Mila M.
T1  - Active zone compaction correlates with presynaptic homeostatic potentiation
JF  - Cell Reports
N2  - Neurotransmitter release is stabilized by homeostatic plasticity. Presynaptic homeostatic potentiation (PHP) operates on timescales ranging from minute- to life-long adaptations and likely involves reorganization of presynaptic active zones (AZs). At Drosophila melanogaster neuromuscular junctions, earlier work ascribed AZ enlargement by incorporating more Bruchpilot (Brp) scaffold protein a role in PHP. We use localization microscopy (direct stochastic optical reconstruction microscopy [dSTORM]) and hierarchical density-based spatial clustering of applications with noise (HDBSCAN) to study AZ plasticity during PHP at the synaptic mesoscale. We find compaction of individual AZs in acute philanthotoxin-induced and chronic genetically induced PHP but unchanged copy numbers of AZ proteins. Compaction even occurs at the level of Brp subclusters, which move toward AZ centers, and in Rab3 interacting molecule (RIM)-binding protein (RBP) subclusters. Furthermore, correlative confocal and dSTORM imaging reveals how AZ compaction in PHP translates into apparent increases in AZ area and Brp protein content, as implied earlier.
KW  - active zone
KW  - Bruchpilot
KW  - RIM-binding protein
KW  - compaction
KW  - homeostasis
KW  - presynaptic plasticity
KW  - super-resolution microscopy
Y1  - 2021
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-265497
VL  - 37
IS  - 1
ER  - 
TY  - JOUR
A1  - Markert, Sebastian Matthias
A1  - Britz, Sebastian
A1  - Proppert, Sven
A1  - Lang, Marietta
A1  - Witvliet, Daniel
A1  - Mulcahy, Ben
A1  - Sauer, Markus
A1  - Zhen, Mei
A1  - Bessereau, Jean-Louis
A1  - Stigloher, Christian
T1  - Filling the gap: adding super-resolution to array tomography for correlated ultrastructural and molecular identification of electrical synapses at the C. elegans connectome
JF  - Neurophotonics
N2  - Correlating molecular labeling at the ultrastructural level with high confidence remains challenging. Array tomography (AT) allows for a combination of fluorescence and electron microscopy (EM) to visualize subcellular protein localization on serial EM sections. Here, we describe an application for AT that combines near-native tissue preservation via high-pressure freezing and freeze substitution with super-resolution light microscopy and high-resolution scanning electron microscopy (SEM) analysis on the same section. We established protocols that combine SEM with structured illumination microscopy (SIM) and direct stochastic optical reconstruction microscopy (dSTORM). We devised a method for easy, precise, and unbiased correlation of EM images and super-resolution imaging data using endogenous cellular landmarks and freely available image processing software. We demonstrate that these methods allow us to identify and label gap junctions in Caenorhabditis elegans with precision and confidence, and imaging of even smaller structures is feasible. With the emergence of connectomics, these methods will allow us to fill in the gap-acquiring the correlated ultrastructural and molecular identity of electrical synapses.
KW  - caenorhabditis elegans
KW  - localization micoscopy
KW  - fluorescent-probes
KW  - junction proteins
KW  - resolution limit
KW  - direct stochasticoptical reconstruction microscopy
KW  - structured illumination microscopy
KW  - correlative light and electron microscopy
KW  - gap junction
KW  - neural circuits
KW  - nervous-system
KW  - image data
KW  - reconstruction
KW  - innexins
KW  - super-resolution microscopy
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-187292
VL  - 3
IS  - 4
ER  - 
TY  - JOUR
A1  - Ehmann, Nadine
A1  - Sauer, Markus
A1  - Kittel, Robert J.
T1  - Super-resolution microscopy of the synaptic active zone
JF  - Frontiers in Cellular Neuroscience
N2  - Brain function relies on accurate information transfer at chemical synapses. At the presynaptic active zone (AZ) a variety of specialized proteins are assembled to complex architectures, which set the basis for speed, precision and plasticity of synaptic transmission. Calcium channels are pivotal for the initiation of excitation-secretion coupling and, correspondingly, capture a central position at the AZ. Combining quantitative functional studies with modeling approaches has provided predictions of channel properties, numbers and even positions on the nanometer scale. However, elucidating the nanoscopic organization of the surrounding protein network requires direct ultrastructural access. Without this information, knowledge of molecular synaptic structure-function relationships remains incomplete. Recently, super-resolution microscopy (SRM) techniques have begun to enter the neurosciences. These approaches combine high spatial resolution with the molecular specificity of fluorescence microscopy. Here, we discuss how SRM can be used to obtain information on the organization of AZ proteins
KW  - excitation-secretion coupling
KW  - Ca\(^{2+}\) channels
KW  - structure-function relationships
KW  - super-resolution microscopy
KW  - active zone
KW  - presynaptic calcium
KW  - neurotransmitter release
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148997
VL  - 9
IS  - 7
ER  -