When the standing cell gradually became motile again, the resumption of cell motion was in a sequence very similar to the Hesperidin guided movement undertaken by the cells when they first interacted with the linear FBN path. The change of cell Dyclonine HCl motility was not due to the UV illumination used by uncaging as mock photolysis did not affect the random migration of the cells. In Fig. 1G, cell migration tracks before and after calcium uncaging are analyzed among cells that were approaching the FBN path from different directions. We found that no matter from which angle the cell was about to traverse the FBN trail, the burst increase of calcium was able to convert the crossing event into motion guided by the FBN path. This suggests that the calcium increase was able to transiently resensitize and render the cell responsive to the substrate navigation and reinitiated a period of ECM-directed movement. The reappearance of IRM darkness when motility resumed suggested that the cells were becoming more ����adhesive���� to the ECM substrate. This could happen if the calcium transient somehow activated the integrin receptors. To test this possibility, we performed immuno-fluorescence staining to localize activeform integrinb1 before and after calcium uncaging. As shown in Fig. 2E, the cells receiving either mock photolysis or caged compound loading alone contained only low abundance of activeform integrinb1 over the entire lamellar region. On the other hand, calcium uncaging for just 5 min was able to increase and/or redistribute active-form integrinb1; more staining signal was noted at the lamella near the leading edge or where the lamella interacted with the FBN path than elsewhere. Dithiothreitol or MnCl2 have been shown to ����activate���� integrins by causing conformational changes of the integrin molecule. Indeed, treating fish keratocytes with MnCl2 resulted in a profound increase in active-form integrinb1; however, the increased active-form integrinb1 induced by such a chemical was found to be located over the entire lamella, rather than near the leading edge, which was the situation when calcium uncaging was applied.