Fig. 5
From: Regulation of Integrin Adhesions by Varying the Density of Substrate-Bound Epidermal Growth Factor
A comparison between cell response to immobilized and soluble EGF as a function of RGD density and total EGF amounts. For comparison, the amounts of immobilized and soluble EGF are calculated for the given well area or the given volume, respectively. The 70th percentile of the cell area (b) and cell aspect ratio (c) are summarized for cells plated on either 12 (dashed line) or 46 (solid line) pmol/cm2 RGD-modified surfaces as a function of the amount of immobilized (Imm dark circles) or soluble (Sol empty diamond) EGF. The average numbers of focal adhesions per cell as a function of EGF are presented for cells plated on 46 pmol/cm2 RGD surfaces (a). All results are expressed as mean ± confidence intervals (CI). Number of FAs per cell or cell area for cells plated on 46 pmol/cm2 RGD surfaces and (4.19 ± 1.04) × 103 fmol immobilized EGF that were significantly different from the same parameters of cells exposed to the same amount of soluble EGF at the P-value level P < 0.05 are denoted by one asterisks. This mark also indicate the P value level for the differences between the parameters of cells plated on (0.75 ± 0.28) × 103 and (4.19 ± 1.04) × 103 fmol immobilized EGF. Aspect ratio of cells plated on 12 or 46 pmol/cm2 RGD surfaces and (4.19 ± 1.04) × 103 fmol immobilized EGF differed from cells plated on RGD only surfaces at a P-value of P < 0.05 (*) and P < 0.01 (**), respectively. Bottom panel images of zyxin- and actin-labeled A431 cells, plated on surfaces modified with 46 pmol/cm2 RGD and various amounts of immobilized (d) or soluble EGF (e). Cells were incubated on the different surfaces for 5 h, and then fixed and stained for zyxin and actin. Scale bar 15 μm