Fig. 2. ₄ß₁-Integrin is involved in MK-induced migration. (A) Expression of ₄ß₁-integrin on the surface of UMR-106 cells as revealed by flow cytometry. UMR cells were incubated with rat anti-mouse-ß₁-integrin or mouse anti-rat-₄-integrin antibody, and stained with FITC/anti-rat-IgG or Alexa-Fluor 488-anti-mouse IgG. The negative controls without the primary antibody are indicated with light lines, whereas the signals from integrin staining are shown with a dark line. (B) Involvement of ₄ß₁-integrin in MK-induced migration. The lower surface of the Chemotaxicell filter was coated with MK or poly-L-lysine (PLL) and a migration assay using UMR-106 cells was performed. Ten fields at 400x magnification per filter were counted to determine the number of migrated cells (one field corresponds to 1/160th of the entire surface of the filter). The results are expressed as a ratio to the value obtained without the addition of reagents (PBS). The value is the mean ± s.e.m. (n=3). *, P<0.001 versus PBS or IgG. V10, the GPEILDVPST sequence; RGD, the GRGDS sequence.