Focal adhesions are cellular structures that connect a cell to the underlying extracellular matrix, and play important roles in cell migration, cytoskeletal regulation, and signaling. The complex protein composition and dynamics within focal adhesions have made it difficult to understand their precise architecture. A recent paper uses a new technique called iPALM to determine the nanoscale organization of focal adhesions. This technique allowed for super-resolution images of focal adhesion components, with the added bonus of data indicating the exact depth of each component. From this data, Kanchanawong and colleagues were able to build a precise three-dimensional model of focal adhesion organization. Images above show the localization of integrin and actin using iPALM, with color-coding indicating the depth of each protein relative to the plasma membrane of the cell. When looking at a side view of the focal adhesion (bottom images), the yellow coding of integrin reveals that it resides closely to the plasma membrane on the coverglass (indicated by 0), while actin was found deeper in the cell.
Kanchanawong, P., Shtengel, G., Pasapera, A., Ramko, E., Davidson, M., Hess, H., & Waterman, C. (2010). Nanoscale architecture of integrin-based cell adhesions Nature, 468 (7323), 580-584 DOI: 10.1038/nature09621