Leishmania aethiopica
            cell‐to‐cell spreading involves caspase‐3, AkT, and NF‐κB but not PKC‐δ activation and involves uptake of LAMP‐1‐positive bodies containing parasites

Medhavi Ranatunga; Rajeev Rai; Simon C. W. Richardson; Paul Dyer; Laurence Harbige; Andrew Deacon; Lauren Pecorino; Giulia T. M. Getti

doi:10.1111/febs.15166

Leishmania aethiopica cell‐to‐cell spreading involves caspase‐3, AkT, and NF‐κB but not PKC‐δ activation and involves uptake of LAMP‐1‐positive bodies containing parasites

FEBS Journal ◽

10.1111/febs.15166 ◽

2019 ◽

Vol 287 (9) ◽

pp. 1777-1797

Author(s):

Medhavi Ranatunga ◽

Rajeev Rai ◽

Simon C. W. Richardson ◽

Paul Dyer ◽

Laurence Harbige ◽

...

Keyword(s):

Caspase 3 ◽

Cell Spreading ◽

Leishmania Aethiopica

Download Full-text

Cardiac myocytes cultured on a basement membrane extract of the ehs tumor

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100142979 ◽

1986 ◽

Vol 44 ◽

pp. 270-271

Author(s):

L. Terracio ◽

A. Dewey ◽

K. Rubin ◽

T.K. Borg

Keyword(s):

Extracellular Matrix ◽

Basement Membrane ◽

Cardiac Myocytes ◽

Normal Tissue ◽

Cell Spreading ◽

Collagen Iv ◽

Basement Membrane Extract ◽

Membrane Extract ◽

Growth Development ◽

Multicellular Organisms

The recognition and interaction of cells with the extracellular matrix (ECM) effects the normal physiology as well as the pathology of all multicellular organisms. These interactions have been shown to influence the growth, development, and maintenance of normal tissue function. In previous studies, we have shown that neonatal cardiac myocytes specifically interacts with a variety of ECM components including fibronectin, laminin, and collagens I, III and IV. Culturing neonatal myocytes on laminin and collagen IV induces an increased rate of both cell spreading and sarcomerogenesis.

Download Full-text

HVEM Analysis of Microfilament Patterns in The Margins of Tissue Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s1431927600003512 ◽

1980 ◽

Vol 38 ◽

pp. 808-811

Author(s):

Carol Allen

Keyword(s):

Cell Movement ◽

Cell Spreading ◽

Living Cells ◽

Tissue Cell ◽

Large Sample Size ◽

Cell Periphery ◽

Whole Cell ◽

Critical Point Drying ◽

Lamellar Region ◽

Tissue Cells

When provided with a suitable solid substrate, tissue cells undergo a rapid conversion from the spherical form expressed in suspension culture to a characteristic flattened morphology. As a result of this conversion, called cell spreading, the cell nucleus and organelles come to occupy a central region of “deep cytoplasm” which slopes steeply into a peripheral “lamellar” region less than 1 pm thick at its outer edge and generally free of cell organelles. Cell spreading is accomplished by a continuous outward repositioning of the lamellar margins. Cell translocation on the substrate results when the activity of the lamellae on one side of the cell become dominant. When this occurs, the cell is “polarized” and moves in the direction of the “leading lamellae”. Careful analysis of tissue cell locomotion by time-lapse microphotography (1) has shown that the deformational movements of the leading lamellae occur in a repeating cycle of advance and retreat in the direction of cell movement and that the rate of such deformations are positively correlated with the speed of cell movement. In the present study, the physical basis for these movements of the cell margin has been examined by comparative light microscopy of living cells with whole-mount electron microscopy of fixed cells. Ultrastructural observations were made on tissue cells grown on Formvar-coated grids, fixed with glutaraldehyde, further processed by critical-point drying, and then photographed in the High Voltage Electron Microscope. This processing and imaging system maintains the 3-dimensional organization of the whole cell, the relationship of the cell to the substrate, and affords a large sample size which facilitates quantitative analysis. Comparative analysis of film records of living cells with the whole-cell micrographs revealed that specific patterns of microfilament organization consistently accompany recognizable stages of lamellar formation and movement. The margins of spreading cells and the leading lamellae of locomoting cells showed a similar pattern of MF repositionings (Figs. 1-4). These results will be discussed in terms of a working model for the mechanics of lamellar motility which includes the following major features: (a) lamellar protrusion results when an intracellular force is exerted at a locally weak area of the cell periphery; (b) the association of cortical MFs with one another determines the local resistance to this force; (c) where MF-to-MF association is weak, the cell periphery expands and some cortical MFs are dragged passively forward; (d) contact of the expanded area with the substrate then triggers the lateral association and reorientation of these cortical MFs into MF bundles parallel to the direction of the expansion; and (e) an active interaction between these MF bundles associated with the cortex of the expanded lamellae and the cortical MFs which remained in the sub-lamellar region then pulls the latter MFs forward toward the expanded area. Thus, the advance of the cell periphery on the substrate occurs in two stages: a passive phase in which some cortical MFs are dragged outward by the force acting to expand the cell periphery, and an active phase in which additional cortical MFs are pulled forward by interaction with the first set. Subsequent interactions between peripheral microfilament bundles and filaments in the deeper cytoplasm could then transmit the advance gained by lamellar expansion to the bulk of the cytoplasm.

Download Full-text