Category: Adhesions

Cell–cell contacts: desmosomes visualized via desmoplakin

3/21/2017

Z-stack with overlay

Low magnification timelapse

Figure. Movies of desmoplakin in desmosomes. Top: Z-stack of live hiPS cells expressing mEGFP-tagged desmoplakin imaged on a spinning-disk confocal microscope. Images start from the bottom of the cells and end at the top. The right panel shows the left panel overlaid onto the equivalent transmitted light image. Bottom: timelapse movie of a hiPS cell colony expressing mEGFP-tagged desmoplakin. Images were collected in 3D every 4 minutes for 8 hours on a spinning-disk confocal microscope. Images are maximum intensity projections; playback speed is 2400x real time.

Observations

Desmoplakin is involved in the linkage of intermediate filaments to cell-cell adhesion sites (desmosomes) in epithelial cells. These desmosomes are seen as small puncta at apical cell-cell boundaries.
In hiPS cells, desmoplakin puncta are not visible in all cells. However, when present there are between 1 and ~20 puncta present per cell.
There may be position-dependent differences in number of desmosomes depending on the spatial location of a cell within a colony. For example, we observe differences between the number of desmosomes in the tightly-packed centers of colonies vs. the flatter, less epithelial-like cells at the edges of colonies; however, this is a casual rather than a rigorous observation.
Desmosomes stay intact during cell division

Cell-substrate adhesions via Paxillin

3/17/2017

High magnification edge of colony (with overlay)

Low magnification of moving colony

Figure. Movies of paxillin in cell-substrate adhesions. Timelapse movies of hiPS cells expressing EGFP-tagged paxillin imaged on a spinning-disk confocal microscope. Left: images were collected as a partial z-stack near the bottom of the cell every 5 minutes for 160 minutes. Image is a maximum intensity projection and movie is sped up 1500x over real time. Right: single slice images near the bottom of the cell taken every 5 minutes for 400 minutes; playback speed is 3000x real time.

Observations

Paxillin is a signaling adaptor that is present in most integrin-mediated sites of adhesions between the cell and the extracellular matrix.
In hiPS cell colonies, paxillin primarily localizes to small adhesions which form puncta at the bottom of cells that are less than 0.5 microns in diameter. These adhesions are dynamic, forming and turning over as the edge of the cell protrudes and retracts. Larger, elongated adhesions are also present in these cells particularly along the more protrusive edges of colonies.

Cell Structure Observations

Cell–cell contacts: desmosomes visualized via desmoplakin

Cell-substrate adhesions via Paxillin

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Cell Structure Observations

​Cell–cell contacts: desmosomes visualized via desmoplakin

Cell-substrate adhesions via Paxillin

About

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The Institute

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Cell–cell contacts: desmosomes visualized via desmoplakin