scholarly journals Superresolution microscopy reveals photoreceptor-specific subciliary location and function of ciliopathy-associated protein, Cep290

JCI Insight ◽  
2021 ◽  
Author(s):  
Valencia L. Potter ◽  
Abigail R. Moye ◽  
Michael A. Robichaux ◽  
Theodore G. Wensel
Keyword(s):  
Superresolution Microscopy ◽  
And Function

scholarly journals Superresolution microscopy reveals photoreceptor-specific subciliary location and function of Cep290

2020 ◽  
Author(s):  
Valencia L. Potter ◽  
Abigail R. Moye ◽  
Michael A. Robichaux ◽  
Theodore G. Wensel
Keyword(s):  
Electron Microscopy ◽  
Epithelial Cells ◽  
Fluorescence Microscopy ◽  
Mouse Models ◽  
Primary Cilia ◽  
Cultured Cells ◽  
Precise Location ◽  
Superresolution Microscopy ◽  
Functional Roles ◽  
And Function

AbstractMutations in the cilium-associated protein CEP290 cause retinal degeneration as part of multi-organ syndromic ciliopathies or as retina-specific diseases. The precise location and the functional roles of CEP290 within cilia and, specifically, the connecting cilia (CC) of photoreceptors, remain unclear. We used superresolution fluorescence microscopy and electron microscopy (TEM) to localize CEP290 in the CC and in primary cilia of cultured cells with sub-diffraction resolution, and to determine effects of CEP290 deficiency. Radially, CEP290 co-localizes with the microtubule doublets and extends beyond them. Longitudinally, it is distributed throughout the length of the CC but is strictly confined to the very base of primary cilia in hRPE-1 cells. We found Y-shaped links, the ciliary sub-structures between microtubules and membrane, at the base of the transition zone in primary cilia of epithelial cells and throughout the length of the CC. Severe CEP290 deficiencies in mouse models did not prevent assembly of cilia or cause obvious mislocalization of ciliary components in early stages of degeneration. They did not lead to loss of the Y-shaped links but caused changes in their structures. These results point to photoreceptor-specific functions of CEP290 essential for CC maturation and stability following the earliest stages of ciliogenesis.

scholarly journals Intact synapse structure and function after combined knockout of PTPδ, PTPσ and LAR

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Javier Emperador-Melero ◽  
Giovanni de Nola ◽  
Pascal S Kaeser
Keyword(s):  
Active Zone ◽  
Protein Tyrosine Phosphatases ◽  
Synaptic Cleft ◽  
Structure And Function ◽  
Independent Study ◽  
Conditional Knockout ◽  
Receptor Protein ◽  
Inhibitory Synapses ◽  
Superresolution Microscopy ◽  
And Function

It has long been proposed that Leukocyte common Antigen-Related Receptor Protein Tyrosine Phosphatases (LAR-RPTPs) are cell-adhesion proteins that control synapse assembly. Their synaptic nanoscale localization, however, is not established, and synapse fine structure after knockout of the three vertebrate LAR-RPTPs (PTPδ, PTPσ and LAR) has not been tested. Here, superresolution microscopy reveals that PTPδ localizes to the synaptic cleft precisely apposed to postsynaptic scaffolds of excitatory and inhibitory synapses. We next assessed synapse structure in newly generated triple-conditional knockout mice for PTPδ, PTPσ and LAR, complementing a recent independent study of synapse function after LAR-RPTP ablation (Sclip and Südhof, 2020). While mild effects on synaptic vesicle clustering and active zone architecture were detected, synapse numbers and their overall structure were unaffected, membrane anchoring of the active zone persisted, and vesicle docking and release were normal. Hence, despite their localization at synaptic appositions, LAR-RPTPs are dispensable for presynapse structure and function.

scholarly journals Cby1 promotes Ahi1 recruitment to a ring-shaped domain at the centriole–cilium interface and facilitates proper cilium formation and function

2014 ◽  
Vol 25 (19) ◽  
pp. 2919-2933 ◽  
Author(s):  
Yin Loon Lee ◽  
Joshua Santé ◽  
Colin J. Comerci ◽  
Benjamin Cyge ◽  
Luis F. Menezes ◽  
...  
Keyword(s):  
Primary Cilia ◽  
Three Dimensional ◽  
Joubert Syndrome ◽  
Cystic Kidneys ◽  
Superresolution Microscopy ◽  
Close Proximity ◽  
And Function ◽  
Canonical Wnt ◽  
Syndrome Protein ◽  
Shaped Domain

Defects in centrosome and cilium function are associated with phenotypically related syndromes called ciliopathies. Cby1, the mammalian orthologue of the Drosophila Chibby protein, localizes to mature centrioles, is important for ciliogenesis in multiciliated airway epithelia in mice, and antagonizes canonical Wnt signaling via direct regulation of β-catenin. We report that deletion of the mouse Cby1 gene results in cystic kidneys, a phenotype common to ciliopathies, and that Cby1 facilitates the formation of primary cilia and ciliary recruitment of the Joubert syndrome protein Arl13b. Localization of Cby1 to the distal end of mature centrioles depends on the centriole protein Ofd1. Superresolution microscopy using both three-dimensional SIM and STED reveals that Cby1 localizes to an ∼250-nm ring at the distal end of the mature centriole, in close proximity to Ofd1 and Ahi1, a component of the transition zone between centriole and cilium. The amount of centriole-localized Ahi1, but not Ofd1, is reduced in Cby1−/− cells. This suggests that Cby1 is required for efficient recruitment of Ahi1, providing a possible molecular mechanism for the ciliogenesis defect in Cby1−/− cells.

scholarly journals Intact synapse structure and function after combined knockout of PTPδ, PTPσ and LAR

2021 ◽  
Author(s):  
Javier Emperador-Melero ◽  
Giovanni de Nola ◽  
Pascal S. Kaeser
Keyword(s):  
Active Zone ◽  
Protein Tyrosine Phosphatases ◽  
Conditional Knockout ◽  
Receptor Protein ◽  
Inhibitory Synapses ◽  
Superresolution Microscopy ◽  
Presynaptic Nerve Terminals ◽  
And Function ◽  
Membrane Anchoring ◽  
Receptor Protein Tyrosine Phosphatases

AbstractIt has long been proposed that Leukocyte common Antigen-Related Receptor Protein Tyrosine Phosphatases (LAR-RPTPs) are cell-adhesion proteins for the control of synapse assembly. Their synaptic nanoscale localization, however, has not been established, and the fine structure of synapses after knockout of the three vertebrate genes for LAR-RPTPs (PTPδ, PTPσ and LAR) has not been tested. Here, we find that PTPδ is precisely apposed to postsynaptic scaffolds at excitatory and inhibitory synapses using superresolution microscopy. We generated triple-conditional knockout mice for PTPδ, PTPσ and LAR to test whether they are essential for synapse structure. While mild effects on synaptic vesicle clustering and active zone architecture were detected, synapse numbers and their overall structure were unaffected, membrane anchoring of the active zone persisted, and vesicle docking and release were normal. We conclude that LAR-RPTPs, despite their localization at synaptic appositions, are dispensable for the organization and function of presynaptic nerve terminals.

scholarly journals The Dictyostelium Centrosome

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2657
Author(s):  
Ralph Gräf ◽  
Marianne Grafe ◽  
Irene Meyer ◽  
Kristina Mitic ◽  
Valentin Pitzen
Keyword(s):  
Protein Interaction ◽  
Structure And Function ◽  
Core Structure ◽  
Considerable Progress ◽  
Superresolution Microscopy ◽  
Interaction Studies ◽  
Composition Structure ◽  
And Function

The centrosome of Dictyostelium amoebae contains no centrioles and consists of a cylindrical layered core structure surrounded by a corona harboring microtubule-nucleating γ-tubulin complexes. It is the major centrosomal model beyond animals and yeasts. Proteomics, protein interaction studies by BioID and superresolution microscopy methods led to considerable progress in our understanding of the composition, structure and function of this centrosome type. We discuss all currently known components of the Dictyostelium centrosome in comparison to other centrosomes of animals and yeasts.

scholarly journals Periodic actin structures in neuronal axons are required to maintain microtubules

2017 ◽  
Vol 28 (2) ◽  
pp. 296-308 ◽  
Author(s):  
Yue Qu ◽  
Ines Hahn ◽  
Stephen E.D. Webb ◽  
Simon P. Pearce ◽  
Andreas Prokop
Keyword(s):  
Close Correlation ◽  
Membrane Skeleton ◽  
Cortical Actin ◽  
Microtubule Organization ◽  
Superresolution Microscopy ◽  
Microtubule Polymerization ◽  
Evolutionarily Conserved ◽  
Neuronal Processes ◽  
And Function ◽  
Actin Rings

Axons are cable-like neuronal processes wiring the nervous system. They contain parallel bundles of microtubules as structural backbones, surrounded by regularly spaced actin rings termed the periodic membrane skeleton (PMS). Despite being an evolutionarily conserved, ubiquitous, highly ordered feature of axons, the function of PMS is unknown. Here we studied PMS abundance, organization, and function, combining versatile Drosophila genetics with superresolution microscopy and various functional readouts. Analyses with 11 actin regulators and three actin-targeting drugs suggest that PMS contains short actin filaments that are depolymerization resistant and sensitive to spectrin, adducin, and nucleator deficiency, consistent with microscopy-derived models proposing PMS as specialized cortical actin. Upon actin removal, we observed gaps in microtubule bundles, reduced microtubule polymerization, and reduced axon numbers, suggesting a role of PMS in microtubule organization. These effects become strongly enhanced when carried out in neurons lacking the microtubule-stabilizing protein Short stop (Shot). Combining the aforementioned actin manipulations with Shot deficiency revealed a close correlation between PMS abundance and microtubule regulation, consistent with a model in which PMS-dependent microtubule polymerization contributes to their maintenance in axons. We discuss potential implications of this novel PMS function along axon shafts for axon maintenance and regeneration.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

The Effect of Oxidized Cholesterol on the Aorta of Rabbits- Scanning Electron Microscopic Observations

1982 ◽  
Vol 40 ◽  
pp. 340-341
Author(s):  
S. K. Pena ◽  
C. B. Taylor ◽  
J. Hill ◽  
J. Safarik
Keyword(s):  
Cholesterol Biosynthesis ◽  
Cholesterol Content ◽  
Arterial Injury ◽  
Electron Microscopic ◽  
Aortic Smooth Muscle ◽  
Oxidized Cholesterol ◽  
Initial Event ◽  
Membrane Structure And Function ◽  
Scanning Electron Microscopic ◽  
And Function

Introduction: Oxidized cholesterol derivatives have been demonstrated in various cell cultures to be very potent inhibitors of 3-hvdroxy-3- methylglutaryl Coenzyme A reductase which is a principle regulator of cholesterol biosynthesis in the cell. The cholesterol content in the cells exposed to oxidized cholesterol was found to be markedly decreased. In aortic smooth muscle cells, the potency of this effect was closely related to the cytotoxicity of each derivative. Furthermore, due to the similarity of their molecular structure to that of cholesterol, these oxidized cholesterol derivatives might insert themselves into the cell membrane, alter membrane structure and function and eventually cause cell death. Arterial injury has been shown to be the initial event of atherosclerosis.

Ultrastructure of developing visual cortical synapses in the cat superior colliculus

1991 ◽  
Vol 49 ◽  
pp. 156-157
Author(s):  
Caroline A. Miller ◽  
Laura L. Bruce
Keyword(s):  
Superior Colliculus ◽  
Phosphate Buffer ◽  
Receptive Fields ◽  
Visual Cortical Area ◽  
Cortical Synapses ◽  
Visual Cortical ◽  
And Function ◽  
Phosphate Buffered Saline ◽  
The Brain ◽  
Cat Superior Colliculus

The first visual cortical axons arrive in the cat superior colliculus by the time of birth. Adultlike receptive fields develop slowly over several weeks following birth. The developing cortical axons go through a sequence of changes before acquiring their adultlike morphology and function. To determine how these axons interact with neurons in the colliculus, cortico-collicular axons were labeled with biocytin (an anterograde neuronal tracer) and studied with electron microscopy.Deeply anesthetized animals received 200-500 nl injections of biocytin (Sigma; 5% in phosphate buffer) in the lateral suprasylvian visual cortical area. After a 24 hr survival time, the animals were deeply anesthetized and perfused with 0.9% phosphate buffered saline followed by fixation with a solution of 1.25% glutaraldehyde and 1.0% paraformaldehyde in 0.1M phosphate buffer. The brain was sectioned transversely on a vibratome at 50 μm. The tissue was processed immediately to visualize the biocytin.

Structural modifications of intercellular junctions.

1978 ◽  
Vol 36 (2) ◽  
pp. 330-331
Author(s):  
J. Metz ◽  
M. Merlo ◽  
W. G. Forssmann
Keyword(s):  
Gap Junctions ◽  
Intercellular Junctions ◽  
Cell Isolation ◽  
Extrahepatic Cholestasis ◽  
Structural Modifications ◽  
Pancreatic Duct Ligation ◽  
Pancreatic Cells ◽  
Duct Ligation ◽  
Thin Sectioning ◽  
And Function

Structure and function of intercellular junctions were studied under the electronmicroscope using conventional thin sectioning and freeze-etch replicas. Alterations of tight and gap junctions were analyzed 1. of exocrine pancreatic cells under cell isolation conditions and pancreatic duct ligation and 2. of hepatocytes during extrahepatic cholestasis.During the different steps of cell isolation of exocrine pancreatic cells, gradual changes of tight and gap junctions were observed. Tight junctions, which formed belt-like structures around the apex of control acinar cells in situ, subsequently diminished, became interrupted and were concentrated into macular areas (Fig. 1). Aggregations of membrane associated particles, which looked similar to gap junctions, were intermixed within tight junctional areas (Fig. 1). These structures continously disappeared in the last stages of the isolation procedure. The intercellular junctions were finally separated without destroying the integrity of the cell membrane, which was confirmed with porcion yellow, lanthanum chloride and horse radish peroxidase.

Sign in / Sign up

Export Citation Format

Share Document