Induction of cell polarization and migration by a gradient of nanoscale variations in adhesive ligand spacing.

Cell interactions with adhesive surfaces play a vital role in the regulation of cell proliferation, viability, and differentiation, and affect multiple biological processes. Since cell adhesion depends mainly on the nature and density of the adhesive ligand molecules, spatial molecular patterning, which enables the modulation of adhesion receptor clustering, might affect both the structural and the signaling activities of the adhesive interaction. We herein show that cells plated on surfaces that present a molecularly defined spacing gradient of an integrin RGD ligand can sense small but consistent differences in adhesive ligand spacing of about 1 nm across the cell diameter, which is approximately 61 mum when the spacing includes 70 nm. Consequently, these positional cues induce cell polarization and initiate cell migration and signaling. We propose that differential positional clustering of the integrin transmembrane receptors is used by cells for exploring and interpreting their environment, at high spatial sensitivity.