Cell-substrate adhesions via Paxillin

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.