​Cell–cell contacts: desmosomes visualized via desmoplakin

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