Synergistic Modulation of Cellular Contractility by Mixed Extracellular Matrices
Figure 3
ECM density-dependent cytoskeletal architecture and focal adhesions of MDA-MB-231 cells. MDA-MB-231 cells were cultured on varying density collagen and fibronectin-coated surfaces. Cells were fixed after 24 hours in culture and stained for F-actin (green) and focal adhesion kinase (FAK) (red). Merged images show the colocalization of the actin fibers and FAK at the points of focal adhesion formation (yellow). Prominent stress fibers were observed across all the conditions. Cells plated on 0.1 μg/cm2 collagen-coated substrates were more rounded and exhibited nuclear/perinuclear FAK localization. At higher collagen concentrations, cells became more elongated with FAK-positive peripheral focal adhesions. FAK localization on fibronectin-coated substrates exhibited an opposite trend to that on collagen-coated substrates with peripheral adhesions at lower densities and nuclear/perinuclear staining at higher densities.
