scholarly journals Requirement of the Cep57-Cep63 Interaction for Proper Cep152 Recruitment and Centriole Duplication

2020 ◽  
Vol 40 (10) ◽  
Author(s):  
Zhuang Wei ◽  
Tae-Sung Kim ◽  
Jong Il Ahn ◽  
Lingjun Meng ◽  
Yaozong Chen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Three Dimensional ◽  
Structure And Function ◽  
Binding Domain ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Centriole Duplication ◽  
And Function ◽  
Mutant Cells

ABSTRACT Cep57 has been characterized as a component of a pericentriolar complex containing Cep63 and Cep152. Interestingly, Cep63 and Cep152 self-assemble into a pericentriolar cylindrical architecture, and this event is critical for the orderly recruitment of Plk4, a key regulator of centriole duplication. However, the way in which Cep57 interacts with the Cep63-Cep152 complex and contributes to the structure and function of Cep63-Cep152 self-assembly remains unknown. We demonstrate that Cep57 interacts with Cep63 through N-terminal motifs and associates with Cep152 via Cep63. Three-dimensional structured illumination microscopy (3D-SIM) analyses suggested that the Cep57-Cep63-Cep152 complex is concentrically arranged around a centriole in a Cep57-in and Cep152-out manner. Cep57 mutant cells defective in Cep63 binding exhibited improper Cep63 and Cep152 localization and impaired Sas6 recruitment for procentriole assembly, proving the significance of the Cep57-Cep63 interaction. Intriguingly, Cep63 fused to a microtubule (MT)-binding domain of Cep57 functioned in concert with Cep152 to assemble around stabilized MTs in vitro. Thus, Cep57 plays a key role in architecting the Cep63-Cep152 assembly around centriolar MTs and promoting centriole biogenesis. This study may offer a platform to investigate how the organization and function of the pericentriolar architecture are altered by disease-associated mutations found in the Cep57-Cep63-Cep152 complex.

scholarly journals Cohesin Releasing Factor WAPL Regulates Genome Structure and Function of Mature T Cells

2021 ◽  
Author(s):  
Yaping Sun ◽  
Gabrielle A. Dotson ◽  
Lindsey A. Muir ◽  
Scott Ronquist ◽  
Katherine Oravecz-Wilson ◽  
...  
Keyword(s):  
T Cells ◽  
Hematopoietic Cell Transplantation ◽  
Genome Structure ◽  
3D Structure ◽  
Three Dimensional ◽  
Structure And Function ◽  
Cell Functions ◽  
And Function

ABSTRACTThe cohesin complex modulates gene expression and cellular functions by shaping three-dimensional (3D) organization of chromatin. WAPL, cohesin’s DNA releasing factor, regulates 3D chromatin architecture. The 3D genome structure and its relevance to mature T cell functions is not well understood. We show that in vivo lymphopenic expansion, and allo-antigen driven proliferation, alters the 3D structure and function of the genome in mature T cells. Conditional deletion of Wapl in T cells reduced long-range genomic interactions, altered chromatin A/B compartments and the topologically associating domains (TAD) of the chromatin in T cells at baseline. Comparison of chromatin structure in normal and WAPL-deficient T cells after lymphopenic and allo-antigen driven stimulation revealed reduced loop extensions with changes in cell cycling genes. WAPL-mediated changes in 3D architecture of chromatin regulated activation, cycling and proliferation of T cells in vitro and in vivo. Finally, WAPL-deficient T cells caused reduced severity of graft-versus-host disease following experimental allogeneic hematopoietic cell transplantation. These data collectively characterize 3D genomic architecture of T cells in vivo and demonstrate biological and clinical implications for its disruption by cohesin releasing factor WAPL.

scholarly journals Filopodome mapping identifies p130Cas as a mechanosensitive regulator of filopodia stability

2018 ◽  
Author(s):  
Guillaume Jacquemet ◽  
Rafael Saup ◽  
Hellyeh Hamidi ◽  
Mitro Miihkinen ◽  
Johanna Ivaska
Keyword(s):  
Binding Sites ◽  
Focal Adhesions ◽  
Structure And Function ◽  
Structured Illumination ◽  
Structured Illumination Microscopy ◽  
Cell Adhesion And Migration ◽  
And Migration ◽  
Cellular Behaviour ◽  
And Function ◽  
Fine Tune

AbstractFilopodia are adhesive cellular protrusions specialised in the detection of extracellular matrix (ECM)-derived cues. While ECM engagement at focal adhesions is known to trigger the recruitment of hundreds of proteins (“adhesome”) to fine-tune cellular behaviour, the components of the filopodia adhesions remain undefined. Here, we performed a structured illumination microscopy-based screen to map the localisation of 80 target proteins, linked to cell adhesion and migration, within filopodia. We demonstrate preferential enrichment of several adhesion proteins to either filopodia tips, filopodia shafts, or shaft subdomains suggesting divergent, spatially restricted functions for these proteins. Moreover, proteins with phospho-inositide (PI) binding sites are particularly enriched in filopodia. This, together with the strong localisation of PI(3,4)P2 in filopodia tips, predicts critical roles for PIs in regulating filopodia ultra-structure and function. Our mapping further reveals that filopodia adhesions consist of a unique set of proteins, the filopodome, that are distinct from classical nascent adhesions, focal adhesions and fibrillar adhesions. Using live imaging, we observe that filopodia adhesions can give rise to nascent adhesions, which, in turn, form focal adhesions. Finally, we demonstrate that p130Cas (BCAR1) is recruited to filopodia tips via its CCHD domain and acts as a mechanosensitive regulator of filopodia stability.

scholarly journals Fast widefield imaging of neuronal structure and function with optical sectioning in vivo

2020 ◽  
Vol 6 (19) ◽  
pp. eaaz3870 ◽  
Author(s):  
Ziwei Li ◽  
Qinrong Zhang ◽  
Shih-Wei Chou ◽  
Zachary Newman ◽  
Raphaël Turcotte ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
In Vivo Imaging ◽  
Neuromuscular Junctions ◽  
Structure And Function ◽  
Structured Illumination ◽  
Neuronal Structure ◽  
Optical Sectioning ◽  
Structured Illumination Microscopy ◽  
And Function

Optical microscopy, owing to its noninvasiveness and subcellular resolution, enables in vivo visualization of neuronal structure and function in the physiological context. Optical-sectioning structured illumination microscopy (OS-SIM) is a widefield fluorescence imaging technique that uses structured illumination patterns to encode in-focus structures and optically sections 3D samples. However, its application to in vivo imaging has been limited. In this study, we optimized OS-SIM for in vivo neural imaging. We modified OS-SIM reconstruction algorithms to improve signal-to-noise ratio and correct motion-induced artifacts in live samples. Incorporating an adaptive optics (AO) module to OS-SIM, we found that correcting sample-induced optical aberrations was essential for achieving accurate structural and functional characterizations in vivo. With AO OS-SIM, we demonstrated fast, high-resolution in vivo imaging with optical sectioning for structural imaging of mouse cortical neurons and zebrafish larval motor neurons, and functional imaging of quantal synaptic transmission at Drosophila larval neuromuscular junctions.

scholarly journals Tissue Engineered Bands of Büngner for Accelerated Motor and Sensory Axonal Outgrowth

2020 ◽  
Vol 8 ◽  
Author(s):  
Kate V. Panzer ◽  
Justin C. Burrell ◽  
Kaila V. T. Helm ◽  
Erin M. Purvis ◽  
Qunzhou Zhang ◽  
...  
Keyword(s):  
Schwann Cell ◽  
Schwann Cells ◽  
Motor Neurons ◽  
Self Assembly ◽  
Axon Regeneration ◽  
Three Dimensional ◽  
Segmental Defect ◽  
3D Matrix ◽  
And Function

Following peripheral nerve injury comprising a segmental defect, the extent of axon regeneration decreases precipitously with increasing gap length. Schwann cells play a key role in driving axon re-growth by forming aligned tubular guidance structures called bands of Büngner, which readily occurs in distal nerve segments as well as within autografts – currently the most reliable clinically-available bridging strategy. However, host Schwann cells generally fail to infiltrate large-gap acellular scaffolds, resulting in markedly inferior outcomes and motivating the development of next-generation bridging strategies capable of fully exploiting the inherent pro-regenerative capability of Schwann cells. We sought to create preformed, implantable Schwann cell-laden microtissue that emulates the anisotropic structure and function of naturally-occurring bands of Büngner. Accordingly, we developed a biofabrication scheme leveraging biomaterial-induced self-assembly of dissociated rat primary Schwann cells into dense, fiber-like three-dimensional bundles of Schwann cells and extracellular matrix within hydrogel micro-columns. This engineered microtissue was found to be biomimetic of morphological and phenotypic features of endogenous bands of Büngner, and also demonstrated 8 and 2× faster rates of axonal extension in vitro from primary rat spinal motor neurons and dorsal root ganglion sensory neurons, respectively, compared to 3D matrix-only controls or planar Schwann cells. To our knowledge, this is the first report of accelerated motor axon outgrowth using aligned Schwann cell constructs. For translational considerations, this microtissue was also fabricated using human gingiva-derived Schwann cells as an easily accessible autologous cell source. These results demonstrate the first tissue engineered bands of Büngner (TE-BoBs) comprised of dense three-dimensional bundles of longitudinally aligned Schwann cells that are readily scalable as implantable grafts to accelerate axon regeneration across long segmental nerve defects.

scholarly journals Crystallizing the function of the magnetosome membrane mineralization protein Mms6

2016 ◽  
Vol 44 (3) ◽  
pp. 883-890 ◽  
Author(s):  
Sarah S. Staniland ◽  
Andrea E. Rawlings
Keyword(s):  
Self Assembly ◽  
Marked Effect ◽  
Magnetotactic Bacteria ◽  
Structure And Function ◽  
In Vitro Methods ◽  
The Subject ◽  
Key Features ◽  
And Function

The literature on the magnetosome membrane (MM) protein, magnetosome membrane specific6 (Mms6), is reviewed. Mms6 is native to magnetotactic bacteria (MTB). These bacteria take up iron from solution and biomineralize magnetite nanoparticles within organelles called magnetosomes. Mms6 is a small protein embedded on the interior of the MM and was discovered tightly associated with the formed mineral. It has been the subject of intensive research as it is seen to control the formation of particles both in vivo and in vitro. Here, we compile, review and discuss the research detailing Mms6’s activity within the cell and in a range of chemical in vitro methods where Mms6 has a marked effect on the composition, size and distribution of synthetic particles, with approximately 21 nm in size for solution precipitations and approximately 90 nm for those formed on surfaces. Furthermore, we review and discuss recent work detailing the structure and function of Mms6. From the evidence, we propose a mechanism for its function as a specific magnetite nucleation protein and summaries the key features for this action: namely, self-assembly to display a charged surface for specific iron binding, with the curvature of the surfaces determining the particle size. We suggest these may aid design of biomimetic additives for future green nanoparticle production.

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Structure and function of neural networks in the retina

1988 ◽  
Vol 46 ◽  
pp. 26-27
Author(s):  
Peter Sterling
Keyword(s):  
Ganglion Cells ◽  
Three Dimensional ◽  
Structure And Function ◽  
Synaptic Connections ◽  
Visual Axis ◽  
One Dimensional ◽  
Cat Retina ◽  
Ultrathin Sections ◽  
And Function ◽  
Insight Into

The synaptic connections in cat retina that link photoreceptors to ganglion cells have been analyzed quantitatively. Our approach has been to prepare serial, ultrathin sections and photograph en montage at low magnification (˜2000X) in the electron microscope. Six series, 100-300 sections long, have been prepared over the last decade. They derive from different cats but always from the same region of retina, about one degree from the center of the visual axis. The material has been analyzed by reconstructing adjacent neurons in each array and then identifying systematically the synaptic connections between arrays. Most reconstructions were done manually by tracing the outlines of processes in successive sections onto acetate sheets aligned on a cartoonist's jig. The tracings were then digitized, stacked by computer, and printed with the hidden lines removed. The results have provided rather than the usual one-dimensional account of pathways, a three-dimensional account of circuits. From this has emerged insight into the functional architecture.

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