Figure 6.

(A) l-selectin triggering stimulates Rac2. Rac2 was immunoprecipitated from [³²P_i]-labeled, Dreg56-treated Jurkat cells and the increase of GTP binding was analyzed by autoradiography. (B) Inhibition of endogenous Ras by N17Ras prevents Rac2 and Ras activation upon l-selectin triggering. Transfection of the vector did not affect l-selectin-induced Rac2 or Ras stimulation. Rac2 or Ras activity in CD20⁺ sorted cells was determined as above. (C) l-selectin triggering leads to synthesis of O₂⁻ in Jurkat and in JCaM1.6+Lck cells. Genetic deficiency of p56^lck, inhibition of Ras with N17Ras or of Rac2 by antisense oligonucleotides prevents O₂⁻ synthesis. Mean values are ± SD.