scholarly journals Vimentin Intermediate Filaments Mediate Cell Morphology on Viscoelastic Substrates

2022 ◽  
Author(s):  
Maxx Swoger ◽  
Sarthak Gupta ◽  
Elisabeth E. Charrier ◽  
Michael Bates ◽  
Heidi Hehnly ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Cell Morphology ◽  
Mediate Cell

scholarly journals Dynamic structural order of a low complexity domain facilitates assembly of intermediate filaments

2020 ◽  
Author(s):  
Vasily O. Sysoev ◽  
Masato Kato ◽  
Lillian Sutherland ◽  
Rong Hu ◽  
Steven L. McKnight ◽  
...  
Keyword(s):  
Protein Folding ◽  
Intermediate Filaments ◽  
Cell Morphology ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
Low Complexity ◽  
Tail Domain ◽  
Sequence Complexity ◽  
New Form

AbstractThe coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent upon either “head” or “tail” domains of low sequence complexity. Here we confirm that the tail domain required for assembly of Drosophila Tm1 IFs functions by forming labile cross-β interactions. These interactions are seen in polymers made from the tail domain alone as well as assembled IFs formed by the intact Tm1 protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.One Sentence SummaryA new form of protein folding that interconverts between the structured and unstructured states controls assembly of intermediate filaments.

scholarly journals Vimentin intermediate filaments mediate cell shape on visco-elastic substrates

2020 ◽  
Author(s):  
Maxx Swoger ◽  
Sarthak Gupta ◽  
Elisabeth E. Charrier ◽  
Michael Bates ◽  
Heidi Hehnly ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Wound Repair ◽  
Null Mouse ◽  
Polyacrylamide Hydrogels ◽  
Polymeric Networks ◽  
Cytoskeletal Network ◽  
Elastic Substrates ◽  
Sense And Respond ◽  
Mediate Cell

AbstractThe ability of cells to take and change shape is a fundamental feature underlying development, wound repair, and tissue maintenance. Central to this process is physical and signaling interactions between the three cytoskeletal polymeric networks: F-actin, microtubules, and intermediate filaments (IFs). Vimentin is an IF protein that is essential to the mechanical resilience of cells and regulates cross-talk amongst the cytoskeleton, but its role in how cells sense and respond to the surrounding extracellular matrix is largely unclear. To investigate vimentin’s role in substrate sensing, we designed polyacrylamide hydrogels that mimic the elastic and viscoelastic nature of in vivo tissues. Using wild-type and vimentin-null mouse embryonic fibroblasts, we show that vimentin enhances cell spreading on viscoelastic substrates, even though it has little effect in the limit of purely elastic substrates. Our results provide compelling evidence that the vimentin cytoskeletal network is a physical modulator of how cells sense and respond to mechanical properties of their extracellular environment.

scholarly journals Dynamic structural order of a low-complexity domain facilitates assembly of intermediate filaments

2020 ◽  
Vol 117 (38) ◽  
pp. 23510-23518
Author(s):  
Vasiliy O. Sysoev ◽  
Masato Kato ◽  
Lillian Sutherland ◽  
Rong Hu ◽  
Steven L. McKnight ◽  
...  
Keyword(s):  
Intermediate Filaments ◽  
Cell Morphology ◽  
Intermediate Filament ◽  
Coiled Coil ◽  
Low Complexity ◽  
Tail Domain ◽  
C Protein ◽  
Sequence Complexity ◽  
Structural Order

The coiled-coil domains of intermediate filament (IF) proteins are flanked by regions of low sequence complexity. Whereas IF coiled-coil domains assume dimeric and tetrameric conformations on their own, maturation of eight tetramers into cylindrical IFs is dependent on either “head” or “tail” domains of low sequence complexity. Here we confirm that the tail domain required for assembly ofDrosophilaTm1-I/C IFs functions by forming labile cross-β interactions. These interactions are seen in polymers made from the tail domain alone, as well as in assembled IFs formed by the intact Tm1-I/C protein. The ability to visualize such interactions in situ within the context of a discrete cellular assembly lends support to the concept that equivalent interactions may be used in organizing other dynamic aspects of cell morphology.

Filaments and membranes in the mitotic apparatus

1983 ◽  
Vol 41 ◽  
pp. 544-547
Author(s):  
Kent McDonald
Keyword(s):  
Intermediate Filaments ◽  
Mitotic Spindle ◽  
Mitotic Apparatus ◽  
Light Microscope Level ◽  
Microtubule Associated Proteins ◽  
Recent Developments ◽  
Associated Proteins ◽  
Force Generator ◽  
Spindle Function ◽  
Antibody Technology

At the light microscope level the recent developments and interest in antibody technology have permitted the localization of certain non-microtubule proteins within the mitotic spindle, e.g., calmodulin, actin, intermediate filaments, protein kinases and various microtubule associated proteins. Also, the use of fluorescent probes like chlorotetracycline suggest the presence of membranes in the spindle. Localization of non-microtubule structures in the spindle at the EM level has been less rewarding. Some mitosis researchers, e.g., Rarer, have maintained that actin is involved in mitosis movements though the bulk of evidence argues against this interpretation. Others suggest that a microtrabecular network such as found in chromatophore granule movement might be a possible force generator but there is little evidence for or against this view. At the level of regulation of spindle function, Harris and more recently Hepler have argued for the importance of studying spindle membranes. Hepler also believes that membranes might play a structural or mechanical role in moving chromosomes.

Quantitative Freeze Fracture Studies of Gap Junctions in Somatic Cell Hybrids, Their Parents, and Revertants

1976 ◽  
Vol 34 ◽  
pp. 218-219
Author(s):  
W. J. Larsen ◽  
R. Azarnia ◽  
W. R. Loewenstein
Keyword(s):  
Gap Junctions ◽  
Striated Muscle ◽  
Freeze Fracture ◽  
Cell Movement ◽  
Dye Molecules ◽  
Somatic Cell Hybrids ◽  
Cell Coupling ◽  
Normal Cells ◽  
Mediate Cell ◽  
Almost All

Although the physiological significance of the gap junction remains unspecified, these membrane specializations are now recognized as common to almost all normal cells (excluding adult striated muscle and some nerve cells) and are found in organisms ranging from the coelenterates to man. Since it appears likely that these structures mediate the cell-to-cell movement of ions and small dye molecules in some electrical tissues, we undertook this study with the objective of determining whether gap junctions in inexcitable tissues also mediate cell-to-cell coupling.To test this hypothesis, a coupling, human Lesh-Nyhan (LN) cell was fused with a non-coupling, mouse cl-1D cell, and the hybrids, revertants, and parental cells were analysed for coupling with respect both to ions and fluorescein and for membrane junctions with the freeze fracture technique.

Cell morphology, volume, and surface area determinations from multilevel contouring within HVEM micrographs of serial sections and whole-cell mounts

1987 ◽  
Vol 45 ◽  
pp. 588-589
Author(s):  
M. Marko ◽  
A. Leith ◽  
D. Parsons
Keyword(s):  
Surface Area ◽  
Electron Micrographs ◽  
Cell Morphology ◽  
Individual Variation ◽  
Serial Section ◽  
Stereo Pair ◽  
Complex Structures ◽  
Serial Sections ◽  
Surface Areas ◽  
Computer Based

The use of serial sections and computer-based 3-D reconstruction techniques affords an opportunity not only to visualize the shape and distribution of the structures being studied, but also to determine their volumes and surface areas. Up until now, this has been done using serial ultrathin sections.The serial-section approach differs from the stereo logical methods of Weibel in that it is based on the Information from a set of single, complete cells (or organelles) rather than on a random 2-dimensional sampling of a population of cells. Because of this, it can more easily provide absolute values of volume and surface area, especially for highly-complex structures. It also allows study of individual variation among the cells, and study of structures which occur only infrequently.We have developed a system for 3-D reconstruction of objects from stereo-pair electron micrographs of thick specimens.

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