Fig. 1. Activated keratinocytes migrated processively on laminin 5. (A) Immunofluorescence of precursor laminin 5 deposited by a keratinocyte migrating on exogenous laminin 5 for 3 hours. Arrow, site of initial adhesion. Anti-laminin 5 mAb D2-1 (green), phalloidin (red). Scale bar: 20 µm. (B) mAb D2-1 stains the initial site of adhesion (arrow, A) and the band of deposits that was under the symmetrically spread cell. The cell is no longer in this field. The deposit pattern reflects the change in cell morphology as it polarized and elongated perpendicular to the direction of migration (arrowheads, P) and began linear migration (large arrow). Scale bar: 10 µm. (C) Phase image of a keratinocyte with polarized fan cell morphology (see also Movie 1, http://dev.biologists.org.supplemental/). Large arrow denotes direction of migration. Cell characteristics r, retracted rear, n, nucleus, b, cell body-lamellipodium transition region, L, lamellipodium, f, filopodia. Scale bar: 5 µm. (D) Tracks from 2-hour migration on exogenous laminin 5, overlay of phase image of cells at the end (see also Movie 2, http://dev.biologists.org.supplemental/). Scale bar: 20 µm.