Semaphorin 3A Increases FAK Phosphorylation at Focal Adhesions to Modulate MDA-MB-231 Cell Migration and Spreading on Different Substratum Concentrations

Figure 5

Sema3A increases pFAK³⁹⁷ levels at focal adhesions in cells plated on collagen and fibronectin, but not laminin. (a) Representative images of cells grown on substrata coated with low, intermediate, and high concentrations of collagen. Indirect immunofluorescence of focal adhesions using an antibody for phosphorylated FAK³⁹⁷ (green) and counterstained with phalloidin (red). Scale bar = 10 μm. (b) Sema3A increased the average total surface area of pFAK³⁹⁷ by ~74% on substrata coated with low and intermediate concentrations of collagen, while Sema3A produced an increase of 127% on substrata coated with low concentrations of fibronectin. pFAK³⁹⁷ staining was not statistically different at high coating concentrations of collagen or fibronectin. Interestingly, Sema3A reduced the average total surface area of pFAK³⁹⁷ by 11–29% on all coating concentrations of laminin. (c) Relative pFAK³⁹⁷ area as analyzed by the average total surface area occupied by pFAK³⁹⁷ normalized to total cell area as determined by TRITC-phalloidin. Data are presented as average ± SEM from a minimum of 50 cells for each condition. , , and indicate statistical significance relative to IgG1 Fc control; two-sample -test.

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